Developer Compass — Structural Cost Estimator V0.21

Table Index — click to navigate

S — Assumptions & Provenance — sources, confidence, vintage 1 — MT Intensity by Building Typology 1a — Measured US Mass-Timber Buildings 2 — MT Intensity by Structural System 3 — MT Package Pricing — CLT & Glulam 4 — Fire Rating Impact on MT Intensity 5 — NBC 2020 Encapsulation Requirements 5e — MT Insurance — CoC & Operational 6 — Concrete Intensity by Typology & System 6a — CIP Concrete Intensity 12–18 Storeys by Market 6b — Podium Structural Grid — Concrete Intensity 6c — CIP Concrete Intensity by Seismic, Wind & Size 7 — Concrete All-In Placed Rate — 16 Markets 8 — Foundation Calculation Parameters 9 — Transfer Slab Types — Cost & Schedule 10 — Gypsum / Finish Allowance 10a — LCA Embodied Carbon — Concrete Structure 11 — Steel Intensity: Estimator + Benchmarks 12 — Steel Rate by Market (Supply, Erection, Installed) 13 — Steel Add-ons & Fire Rating 14 — This Building’s Steel Cost Build-up 15 — Oil Price Impact on Structural Cost 16 — Carbon Price Impact on Structural Cost 20 — Construction Cost Stack Benchmarks 21 — MT Acoustic Topping Types 22 — Location Cost Index (CCI) — 16 Markets 23 — Parkade, Encapsulation & Conveying Params 24 — Schedule Base Weeks by Typology 25 — Schedule Dynamics — all variables exposed 26 — Core / Lateral Seismic Intensity by City 27 — MT Core System Impacts ✎ editable 28 — Seismic Reference Weights & Core Scaling Table 17 is on the Schedule tab and Tables 18–19 on Configuration; the Financial Estimates panels carry their own Tables 21–23

LiveAssumptions & Provenance

Every input the estimator seeds from a market or location table, with the source it came from and how much weight that source carries. Updates with the selected location.

Table 1Material Intensity by Building Typology (m³/m²)

Building Type	Storeys	FRR	Low	Avg	High	Primary System

Source: Whirlwind Consultants database 200+ MT projects; report Section 2.4.2

Table 1aMeasured US Mass-Timber Buildings — Timber, Concrete & Steel Intensity (validation)

Source	Building	Storeys	n	Low	Median	High	Concrete m³/m²	Steel kg/m²	Notes
CLF WBLCA v2 — US buildings with CLT floors	Education, office, assembly (none residential); 10 in SDC D	1–10	19	0.17	0.21	0.23	0.11	15.6	Superstructure: floors, roof, frame, stairs and any timber walls (the dataset cannot separate them). Low / High = interquartile range. Concrete = toppings, cores and walls above grade; steel excludes rebar.
→ offices only	California, Washington	2–5	5	0.14	0.22	0.25	0.53	12.0	Low / High = min / max.
→ education only	Mostly Washington	1–10	9	0.12	0.19	0.27	0.08	19.3	Low / High = min / max.
Gu & Bergman 2018, USDA FPL-GTR-255 (EBD Table 15)	UMass Olver Design Building, Amherst MA: CLT floors + 245 mm CLT walls, glulam frame	4	1	0.26	0.26	0.26	0.32	34.9	As built, whole building, 8,147 m². Concrete includes foundations, basement walls, the first-floor slab and 100 mm toppings.
Bjarvin 2026, UW PhD dissertation (Table 2)	Google MT1, Sunnyvale CA: CLT floors and walls, glulam frame, CLT roof	5	1	0.30	0.30	0.30	0.17	—	Whole building, 16,955 m²; 3,100 m³ CLT + 2,000 m³ glulam stated. Concrete includes foundations. Its steel figure mixes rebar and non-structural steel, so it is not shown.

Timber columns: mass timber (CLT, glulam, LVL, PSL, LSL, heavy timber) in m³/m² of GFA; CLF records mass, converted at the estimator’s 500 kg/m³ (MT1’s own figures imply 529, so CLF volumes may read about 5% high). For comparison, the estimator prices 0.20 at its default point-support system and 0.15–0.16 for low-rise post and beam (Table 1). Its mass-timber scheme carries no concrete above grade (a screed topping, a CLT or steel core in these runs) and no steel quantity for connections. Held sources: CLF WBLCA Benchmark v2 dataset; USDA FPL-GTR-255 (2018); Bjarvin 2026 (University of Washington). Validation only: these figures check the estimator, they do not set it.
Developer Compass is not affiliated with, endorsed by, licensed by or acting for the Carbon Leadership Forum, the University of Washington, the USDA Forest Service, Google or Atelier Ten. Source names are used for factual reference only.

Table 2Material Intensity by Structural System Type (m³/m²)

Structural System	Modifier	Default Glulam %	Notes

Key correction: adding purlins reduces panel span and therefore panel thickness, lowering total material intensity despite adding members. Post, Beam & Panel has no purlins so panels must span beam-to-beam and are thicker. Source: Whirlwind Consultants project database

Table 3MT Package Pricing Basis ($/m³) — edit frequencies to recalculate weighted average

Edit the % frequency cells below. Weighted averages update live and sync to the main estimator sliders.

Product	$1,000	$1,250	$1,500	$1,750	$2,000	Wtd. Avg
CLT (SPF) — frequency %						$1,700/m³
Total: 100% ⚠ Must sum to 100%
Product	$3,000	$3,500	$4,000	$4,500	$5,000	Wtd. Avg
Glulam (DF) — frequency %						$4,400/m³
Total: 100% ⚠ Must sum to 100%

Includes material, CNC fabrication, project management, design, connections, nominal shipping. Install erection additional 15–30% of pkg. Weighted average syncs to main estimator Glulam/CLT sliders. Source: Whirlwind Consultants project records.

Table 4Fire Rating Impact on Material Intensity — Glulam vs. CLT Split

FRR	Glulam multiplier	CLT multiplier	Design Impact
Encapsulated (0 min exposed)	1.00×	1.00×	Baseline; structure fully covered by drywall
45 min exposed	1.05–1.10×	1.00–1.03×	Minor char allowance on beams; panels largely unaffected
60 min (1 hr)	1.10–1.20×	1.04–1.07×	Moderate beam/column upsizing; CLT panel thickness increase modest
90 min	1.15–1.25×	1.06–1.09×	Significant beam growth; CLT adds one lamination layer
120 min (2 hr)	1.25–1.40×	1.10×	Largest driver for Glulam; CLT adds char layer (approx. +10% volume). Required above 6 st in BC

Glulam and CLT respond differently to FRR because they char differently. Glulam beams and columns must be oversized to maintain structural capacity after the sacrificial char layer burns away — this drives the 25–40% volume increase at 2 hr. CLT panels develop a self-insulating char layer that limits heat penetration; only a single additional lamination is typically required, resulting in approximately 10% more panel volume at 2 hr. These split multipliers are live in the estimator: at 2 hr FRR (residential and office), the Glulam cost component is multiplied by 1.325 and the CLT cost component by 1.10. The 1 hr and encapsulated typologies carry no additional multiplier — their intensity benchmarks already reflect typical 1 hr exposed design.

Table 5NBC 2020 Encapsulation Requirements by Building Type

Building Type / Typology Key	Storeys	Construction Class	Min Rating (min)	Layers	Default Encap%	Exposed Surface Limits	NBC Reference

Sources: NBC 2020 Div B Articles 3.1.4, 3.1.6, 3.2.2.48, 3.2.2.56; Canadian Wood Council EMTC Guide (Ontario); CBHCC Proposed Change Forms 1870 & 1963 (NBC 2025 public review); NRC CLT Fire Research 2023. Encapsulation rating (ULC S146) delays ignition of mass timber — distinct from fire resistance rating (FRR). 2× 12.7 mm Type X gypsum achieves ~50 min encapsulation rating. All EMTC buildings require sprinklers per NFPA 13.

Table 5eMass Timber Insurance — Course of Construction & Operational Benchmarks

Coverage Type	System	Rate (% of TIV/yr)	Premium vs. CIP	Benchmark Project	Key Risk Drivers	Notes
Course of Construction (Builders Risk)	CIP Concrete / Steel	0.50 – 1.10%	Baseline	Halifax 2024: $250K–$475K on ~$45M TIV	Fire, water, theft, collapse	Accrues weekly over full construction schedule. Shorter schedule = lower total cost. Tool default: 0.80%/yr.
Course of Construction (Builders Risk)	Mass Timber	0.88 – 1.67%	+40% to +80%	Halifax 2024: $475K–$750K on same TIV	Exposed timber combustibility pre-encapsulation; moisture swelling; char risk; limited insurer capacity	Premium reflects unprotected timber phase. Once encapsulated & weather-tight, risk profile improves. Sprinklers reduce premium 10–20%.
Operational Building Insurance (Property All-Risk)	CIP Concrete / Steel	0.15 – 0.35%	Baseline	BC mid-rise: $8–14/m²/yr on $3,500–$5,500/m² replacement cost	Fire, water, liability	Applied to replacement cost of completed building. Tool default: $10/m²/yr (≈ 0.25% on $4,000/m²).
Operational Building Insurance (Property All-Risk)	Mass Timber	0.18 – 0.44%	+10% to +25%	Enclosed MT: ~$11–18/m²/yr	Higher replacement cost (timber vs. concrete); residual char-risk perception; some insurers unfamiliar with MT	Lower premium than CoC because building is enclosed and sprinklered. Market improving as MT track record grows. Tool default: +15%.

Course of Construction Insurance Formula

          CoC Cost ($) = TIV × Rate (%/yr) × Schedule (wks) / 52
        

TIVTotal Insured Value = Hard cost ($/m²) × GFA (m²). Includes structure, envelope, MEP — all construction value at risk. RateBase rate (CIP/ST) × (1 + MT premium fraction). MT rate = base × (1 + 0.50) at default 50% premium. ScheduleEach system uses its own computed schedule (weeks). MT’s shorter schedule partially or fully offsets its higher rate. Crossover: MT CoC < CO when schedule saving > rate premium. CrossoverMT CoC = CO CoC when: MT_rate × MT_sched = CO_rate × CO_sched → MT premium% = (CO_sched / MT_sched − 1) × 100%. E.g. 68 wks CO / 37 wks MT − 1 = 84% premium needed for parity.

Example (Halifax 2024 calibration, 12,000 m² GFA, $4,500/m² hard cost = $54M TIV):
CIP at 0.80%/yr × 52 wks: $432,000 — Halifax quote range $250K–$475K ✓
MT at 1.20%/yr × 37 wks: $500,000 — Halifax quote range $475K–$750K ✓
MT total CoC less than CIP despite 50% higher rate, because MT schedule is 29% shorter.

Factors Reducing MT Insurance Premium

Factor	Typical Reduction	Mechanism	Insurer Evidence
NFPA 13 sprinkler system	10–20% rate reduction	Primary fire suppression reduces char propagation risk	Swiss Re, FM Global MT guidelines 2023
Early encapsulation sequencing	5–15%	Timber protected sooner in construction sequence; reduces unprotected exposure window	Broker advisory: Intact, Aviva MT programs
CLT vs. Glulam mix	0–10%	CLT panels self-char more predictably; less variable cross-section	NRC CLT fire research 2023
MT-specialist insurer program	0–30%	Insurers with MT experience (FM Global, Swiss Re, Intact MT) have better loss data — price more accurately	Industry: select broker can access MT-specific programs
Experienced MT contractor	5–10%	Track record of successful MT projects reduces underwriter perceived risk	Underwriter interviews 2024
Net achievable MT premium (best case)	+15% to +30%	Sprinklers + early encap + MT specialist insurer + experienced contractor	Set MT premium slider to 15–30% to model this scenario

Sources: Halifax 2024 broker quotes (Whirlwind Consultants project data); Swiss Re Institute “Mass Timber: Insurability and Risk” 2023; FM Global Property Loss Prevention Data Sheet 1-57 (Combustible Construction); Intact Financial MT Builders Risk program 2024; Aviva Canada Commercial Lines timber advisory 2023; NRC “Fire performance of CLT assemblies” IRC-RR-375, 2023; Canadian Underwriter “Mass Timber Insurance” Nov 2023. Rates expressed as % of Total Insured Value per year. Actual rates depend on project size, location, contractor, sprinkler system, encapsulation schedule, and insurer appetite.

Quantity — how much concrete the frame uses

Table 6Concrete Structural Systems — Intensity, Types & Cost Drivers (m³/m²)

A — Concrete System Types by Building Class

Building Class	Typical System	Slab Type	Lateral / Core	Avg Intensity m³/m²	Used in Estimator	Why This System
LWF Hybrid 2–6 st	CIP flat slab on grade + PT podium	150–200 mm flat plate or PT slab	CIP shear walls / CMU	0.40	✓ 0.40	Developer counterfactual: full 4–6 st CIP alternative to wood-frame; dominates market below 6 st in BC/AB
Mid-Rise Res. 1 hr (4–8 st)	CIP RC flat plate	200–225 mm flat plate, 30 MPa	CIP shear walls	0.45	✓ 0.45	Standard market system BC/AB/ON; 7–10 day floor cycle; repetitive form work; Altus calibrated
Mid-Rise Res. 2 hr (7–12 st)	CIP RC flat plate + heavier core	225–250 mm flat plate, 35 MPa	Thicker CIP shear walls + outriggers	0.50	✓ 0.50	Taller slabs need more punching shear reinforcement; higher seismic demand = thicker walls
Mid-Rise EMTC 13–18 st	CIP post-tensioned flat plate	200–230 mm PT slab, 35–40 MPa	CIP coupled shear walls + transfer slab	0.55	✓ 0.55	PT reduces slab depth but higher MPa + transfer levels add volume; coupled walls increase wall thickness
Office 1 hr (≤6 st)	CIP flat plate or two-way waffle	225–275 mm flat plate or 300 mm waffle	CIP or precast shear walls	0.40	✓ 0.40	Open floor plan requires longer spans → thicker slabs; but lower suite density = less wall volume
Office 2 hr (≤12 st)	CIP flat plate + moment frames	250–300 mm flat plate, 35 MPa	CIP moment frame + shear walls	0.45	✓ 0.45	Higher seismic demand at this height; moment frame adds beam/col volume vs. flat plate only

B — Key Intensity Drivers (use to calibrate override input)

Factor	Intensity Effect	Typical Range	Notes
INCREASES INTENSITY
Higher seismic zone (Vancouver, Victoria)	+0.04–0.08 m³/m²	0.49–0.58 vs. 0.45	Thicker shear walls, more rebar, ductile detailing; significant in Rd=2.0 vs. Rd=4.0 systems
Taller building (each 4 storeys)	+0.02–0.04 m³/m²	Cumulative	Higher shear wall overturning demands; thicker walls at base; outrigger/belt walls add volume
Longer spans (office >9 m)	+0.03–0.06 m³/m²	0.43–0.48 vs. 0.40	Flat plate punching shear governs; slab thickens or drop panels added
Transfer slab / podium level	+0.03–0.10 m³/m²	On affected floors	Concentrated load redistribution; 350–600 mm transfer plate common above grade parking
Below-grade parkade (per basement level)	+0.06–0.12 m³/m²	On parkade floors	300–400 mm flat plate + waterproofing slab; retaining walls; estimator excludes parkade
Higher MPa spec (40–50 MPa)	+5–10% cost	Price, not volume	Higher strength concrete costs more per m³ but allows thinner members — partially offsetting
DECREASES INTENSITY
Post-tensioned flat plate (vs. RC)	−0.02–0.04 m³/m²	0.43–0.47 vs. 0.45–0.50	PT allows 175–200 mm slab vs. 200–250 mm RC; partially offset by PT hardware cost premium ~+$80–120/m³
Precast hollow-core floors	−0.03–0.06 m³/m²	0.39–0.43	Factory-produced; less on-site formed concrete; faster schedule; common in prairie markets
Light seismic zone (prairie cities)	−0.03–0.06 m³/m²	0.39–0.45 vs. 0.45–0.50	Wind governs over seismic in Winnipeg, Saskatoon, Regina; thinner walls possible
Shorter spans (residential ≤7 m)	−0.02–0.04 m³/m²	0.41–0.45	Punching shear not critical; slab can be thinner; typical corridor-access residential layouts

C — Published Intensity Benchmarks (third-party calibration)

Source	Building Type	Intensity (m³/m²)	Market / Year	System
Developer Compass estimate	Mid-rise residential (8–12 st)	0.44–0.52	Vancouver 2025	CIP RC flat plate, 30–35 MPa. Engineering estimate — not an Altus figure: the Altus Cost Guide publishes whole-building $/ft² only and carries no intensity data.
Developer Compass estimate	High-rise residential (13–25 st)	0.50–0.60	Vancouver 2025	CIP PT flat plate + coupled walls. Engineering estimate, source as above.
T&T CMI Q4 2025 †	Mid-rise residential (6–12 st)	0.42–0.55	Toronto / Calgary	CIP RC; range reflects seismic zone difference
CWC Tall Wood Study 2026 †	12-st mid-rise (Dartmouth NS)	0.48–0.52	Halifax 2026	CIP RC; back-calculated from project cost data
BCIT Structural Engineering 2024 †	6-st residential, Vancouver	0.43–0.47	BC 2024	CIP flat plate + CLT shear wall hybrid
Hanscomb Yardsticks 2024 †	4–6 st apartment	0.36–0.44	Canada 2024	RC flat plate; low end prairie, high end coastal seismic
Developer Compass estimate	Mid-rise residential (8 st)	0.40–0.48	Canada adjusted	RC flat plate. Engineering estimate — not an RSMeans figure: the RSMeans City Cost Index is a location multiplier and carries no intensity data.
Estimator defaults	All typologies	0.40–0.55	Canada 2025	Mid-range of above; use override input to adjust for your project

Intensity definition: m³ of placed concrete per m² of gross floor area (GFA). Includes: columns, beams (if any), flat plate or waffle slabs on all above-grade floors, shear walls, core walls, and spandrel beams. Excludes: foundations and pile caps (modelled separately), below-grade parkade slabs, slab-on-grade, exterior cladding backup, and architectural concrete.
Intensities are engineering estimates. No published source tabulates structural concrete intensity in m³/m² for Canadian residential construction; the values above are derived from code-based design calculations and project experience, then sense-checked against published cost data. They are not extracted from any third-party dataset.
Benchmarked against: Altus Group 2026 Canadian Cost Guide (data as at Jan 31 2026); Turner & Townsend CMI Q4 2025 †; CWC/WoodWorks Tall Wood Feasibility Study Dartmouth NS (Feb 2026) †; Hanscomb Yardsticks for Costing 2024 †; BCIT Structural Engineering Program project database 2024 †.
† Source not independently re-verified against the primary document for this release.
Developer Compass is not affiliated with, endorsed by, licensed by or acting for Altus Group, Turner & Townsend, Hanscomb, Gordian/RSMeans, or any other organisation named above. Source names are used for factual reference only and remain the trademarks of their respective owners.

Table 6a12–18 Storey CIP Concrete — Structural Intensity by Market & System (m³/m²)

This height band (EMTC / tall mid-rise) is the primary MT vs. concrete battleground. Intensity varies significantly by seismic zone, slab system, and presence of transfer levels. Section A market rows are Developer Compass engineering estimates. Sections A2 and D are measured or designed project data from held sources. RC = reinforced concrete flat plate | PT = post-tensioned flat plate (dominant system 12+ st Vancouver/Toronto) | Confidence: ★★★★ = held real-project data, n ≥ 10 ★★★ = held real-project data, n 4–9 ★★ = held data, n ≤ 3, or a design study Est. = Developer Compass engineering estimate, no held source.

Market	Seismic Zone	Dominant System	Storeys	Intensity m³/m² GFA			Structural EC kg CO₂e/m²	Confidence	Key Drivers & Notes
A — Structural Intensity by Canadian Market (12–18 st residential, above-grade structure only) — engineering estimates
Market	Seismic Zone	Dominant System	Storeys	Low	Avg	High	Structural EC kg CO₂e/m²	Confidence	Key Drivers & Notes
HIGH SEISMIC — Coastal BC
Vancouver / Metro	High (Sa0.2=0.94g)	PT flat plate + CIP coupled shear walls	12–18	0.50	0.57	0.65	245–295	Est.	Highest seismic demand in Canada. Coupled shear walls 350–500 mm thick. PT slab 190–220 mm. Transfer slab typical at P1.
Victoria	High (Sa0.2=0.85g)	PT flat plate + CIP shear walls	12–18	0.48	0.55	0.62	235–280	Est.	Similar seismic to Vancouver; smaller project scale means less form repetition efficiency. Fewer 15+ st projects — limited direct data. Interpolated from the Vancouver estimate.
ONTARIO — Toronto low-moderate, Ottawa moderate-high
Toronto / GTA	Low-Moderate (Sa0.2=0.14g)	PT flat plate + CIP shear walls	12–18	0.46	0.52	0.60	215–265	Est.	Most 12–18 st market in Canada. PT dominant; lower seismic allows thinner shear walls. High end reflects transfer slabs + mixed-use podium.
Ottawa	Moderate-High (Sa0.2=0.64g)	RC flat plate + CIP shear walls	12–18	0.45	0.51	0.57	210–255	Est.	Fewer PT contractors vs. Toronto; RC flat plate common. Wind governs above 12 st. Limited 15+ st data — extrapolated from the Toronto estimate. Check: Ottawa's NBCC 2020 Sa(0.2) is well above Toronto's; this estimate was made before that was corrected and is likely low.
MODERATE SEISMIC — Québec
Montréal	Moderate (Sa0.2=0.43g)	RC flat plate + CIP shear walls	12–18	0.47	0.53	0.60	220–270	Est.	Higher seismic than Toronto due to Eastern Canada seismic zone. RC flat plate dominates; PT less common. Bill 51 union agreements drive labour cost but not intensity.
LOW SEISMIC — Prairies (wind governs)
Calgary	Low (Sa0.2=0.10g; wind governs)	RC flat plate + CIP shear walls	12–18	0.44	0.50	0.56	200–245	Est.	Wind governs lateral at this height. Thinner shear walls vs. coastal; 200–300 mm typical. RC flat plate standard. Precast hollow-core sometimes used for residential floors.
Edmonton	Low (Sa0.2=0.07g)	RC flat plate + CIP shear walls	12–18	0.43	0.49	0.55	195–240	Est.	Lowest seismic of major cities. Wind governs; thinnest shear walls. Fewer 12+ st projects vs. Calgary. Interpolated from the Calgary estimate.
Winnipeg	Low (Sa0.2=0.12g)	RC flat plate + CIP shear walls	12–18	0.43	0.49	0.55	195–240	Est.	Similar to Edmonton seismically. Very limited 12+ st project data. Precast hollow-core common for residential.
LOW-MODERATE SEISMIC — Atlantic Canada
Halifax / HRM	Low-Moderate (Sa0.2=0.20g)	RC flat plate + CIP shear walls	12–18	0.48	0.54	0.62	240–295	Est.	Higher end reflects limited local contractor competition → less repetition efficiency. High structural EC driven by cement import carbon premium.
A2 — Measured: US and Canadian CIP projects (CLF WBLCA Benchmark v2, above-grade structure only)
Read every row as a band, not a point: each cohort has fewer than 10 projects. Low and High are the cohort's min and max; the bracketed Avg is its median. Intensity = superstructure ready-mix concrete mass ÷ 2,400 kg/m³ (1,850 for mixes labelled lightweight) ÷ GFA; precast excluded. Superstructure covers floors, roof, stairs, frame and core walls. Structural EC = superstructure, A1–A4 (the dataset reports no A5). Screened out: renovations, zero or missing GFA, superstructure below substructure, zero concrete mass, CIP used only as a podium, steel or wood floors, one location conflict. Each figure traces to a CLF `project_index`. These rows validate the calculated intensity; they are not a target to tune it to.
Market	Seismic	Dominant System	Storeys	Intensity m³/m² GFA			Structural EC kg CO₂e/m²	Confidence	Key Drivers & Notes
Market	Seismic	Dominant System	Storeys	Low	Avg	High	Structural EC kg CO₂e/m²	Confidence	Key Drivers & Notes
HIGH SEISMIC — US West Coast (SDC D)
California / Oregon / Washington, all uses	High (SDC D)	PT flat plate + CIP shear walls (6 of 6)	11–20	0.31	(0.36)	0.55	210–251	★★★ (n=6)	3 office, 2 residential, 1 hotel. Four of the six have parking that sits in constructed area but not in GFA; spread over constructed area the median falls about 13%. EC from 5 projects (139 carries no rebar). CLF project_index 46, 56, 65, 139, 147, 169.
→ residential / hotel only	High (SDC D)	PT flat plate + CIP shear walls	11–20	0.31	(0.38)	0.41	236–251	★★ (n=3)	The like-for-like comparison with the Canadian residential rows. Both Oregon projects (139, 147) model lightweight concrete throughout. EC from 2 projects. CLF project_index 65, 139, 147.
CANADA — measured
British Columbia + one unstated province, residential	High (BC, SDC D); other not given	RC flat plate (non-PT, 2 of 2), tower on podium	11–20	0.52	(0.53)	0.54	240–405	★★ (n=2)	Sits beside the Vancouver estimate in section A. Both count parking in constructed area; spread over that area they fall about 20%. Conventionally reinforced, unlike the post-tensioned US towers above. CLF project_index 171, 247.
MODERATE SEISMIC — US (SDC C) — no measured sample; design study shown
Honolulu, HI, office — design study	Moderate (SDC C)	RC pan-joist floor + intermediate moment frames, no walls	12 + basement	0.27 (0.29)			—	★ (n=1 design)	Not measured: CLF v2 holds no US CIP project of 6+ storeys at SDC C (its two SDC C CIP projects, 206 and 267, are 2–5 storeys in Washington). Take-off from the member sizes of the FEMA P-751 (2012) NEHRP design example, Ch. 7: 12 suspended floors on above-grade GFA; the bracketed figure adds the ground-floor slab over the basement. It agrees within 5% with the example's own storey weights. A moment-frame office to ASCE 7-05, not the PT flat plate + core residential the estimator prices. No superstructure EC is held at SDC C; the WoodWorks/KPFF El Paso figure in section D covers structure and foundations.
→ same building, Berkeley, CA	High (SDC D)	RC pan-joist floor + special moment frames + special walls (E-W)	12 + basement	0.31 (0.33)			—	★ (n=1 design)	Shown for the seismic delta on one building: the SDC C design uses 12% less concrete, from smaller beams and columns and no walls. Walls alone show no saving: ATC-76 (NIST GCR 10-917-8) keeps the section of its 12-storey wall archetypes the same from SDC D down to C, and only the boundary steel drops (one SDC C archetype uses a third less wall).
LOW SEISMIC — US (SDC A–B; wind governs)
New York / Texas / Colorado / South-East, all uses	Low (SDC A–B)	Mixed: PT (3), RC flat plate (2)	6+	0.33	(0.45)	0.58	228–447	★★★ (n=5)	Only one project (New York residential, 16–20 st) sits in the 12–18 band, so the cohort is widened to 6+ storeys. It mixes office, lab and residential; the lab and office floors run heavier, and the two residential towers (110 NY, 23 TX) sit at the low end. EC from 4 projects (259 carries no rebar). CLF project_index 4, 23, 110, 111, 259.
B — RC vs. PT Slab System Comparison at 12–18 Storeys
Engineering estimates; no held source. Each intensity is a band, so it fills Low and High.
System	Slab Thickness	Cost Premium vs. RC	Storeys	Intensity m³/m² GFA			EC Impact kg CO₂e/m²	Confidence	Schedule & When to Use
System	Slab Thickness	Cost Premium vs. RC	Storeys	Low	Avg	High	EC Impact kg CO₂e/m²	Confidence	Schedule & When to Use
RC flat plate (baseline)	225–275 mm, 30–35 MPa	—	12–18	0.49	—	0.57	220–270	Est.	8–10 day floor cycle. Lower seismic; shorter spans ≤8 m; prairie markets where PT trades less available.
PT flat plate	190–220 mm, 35–40 MPa	+$80–140/m² slab area	12–18	0.45	—	0.53	205–255	Est.	6–8 day floor cycle (fewer shores). Dominant 12+ st Vancouver/Toronto; longer spans 9–12 m; faster cycle; lower slab dead load reduces column/wall size.
RC waffle / coffered	400–500 mm depth, 30 MPa ribs	+$60–100/m² (complex forms)	12–18	0.38	—	0.46	190–235	Est.	10–14 day floor cycle. Long spans 10–14 m (office); heavy live loads; less common residential; slower due to form complexity.
PT + high-strength concrete (40–50 MPa)	175–200 mm, 40–50 MPa	+$120–180/m²	12–18	0.43	—	0.50	215–265	Est.	6–7 day floor cycle. Premium high-rise 15+ st; allows smallest slab + column sections; net EC similar to standard PT (thinner slab offset by higher cement content for strength).
MT comparison (EMTC 13–18 st)	CLT 175–220 mm + topping 50 mm	+$200–400/m² structural	13–18	0.19	—	0.26	Negative (biogenic C storage)	Est.	3–5 day floor cycle. Timber, not concrete, volume: MT intensity is 50–60% lower than CIP — the core MT advantage at this height. Schedule 30–40% faster than CIP. EC roughly carbon-neutral to carbon-negative depending on biogenic accounting.
C — Intensity Progression by Height (CIP concrete, Vancouver seismic zone)
Shows how intensity increases with height due to shear wall demands, higher MPa, and transfer levels. Developer Compass engineering estimate for the Vancouver seismic zone; no held source. Use to interpolate for specific storey counts.
Height Band	Slab System	Shear Wall Thickness	Storeys	Intensity m³/m² GFA			Structural EC kg CO₂e/m²	Confidence	Intensity Driver & Notes
Height Band	Slab System	Shear Wall Thickness	Storeys	Low	Avg	High	Structural EC kg CO₂e/m²	Confidence	Intensity Driver & Notes
Low-rise	RC flat plate 200 mm	200–250 mm	4–6	0.38	—	0.42	—	Est.	Slab volume dominates; thin walls. LWF counterfactual; gravity governs.
Mid-rise lower	RC flat plate 215 mm	250–300 mm	7–10	0.43	—	0.48	—	Est.	Shear walls thickening; seismic detailing starts. Standard BC/AB/ON mid-rise.
Mid-rise upper	PT flat plate 200 mm	300–350 mm	10–14	0.49	—	0.54	—	Est.	Coupled walls + outriggers emerging; PT savings partially offset wall growth. EMTC lower range; transition to PT.
Tall mid-rise	PT flat plate 195–210 mm	350–450 mm	14–18	0.53	—	0.60	—	Est.	Coupled shear walls dominant; overturning governs; transfer slab typical. EMTC primary range; estimator table 0.48 → 0.53 m³/m² (13–18 st).
High-rise lower	PT flat plate 185–200 mm	400–500 mm	18–25	0.58	—	0.66	—	Est.	Outrigger + belt walls; mechanical floor adds volume; high MPa columns. Above EMTC range; not currently in estimator.
High-rise upper	PT flat plate 185 mm + bands	450–600 mm	25–40	0.65	—	0.75	—	Est.	Core tube + outrigger system; gravity columns shift to high-strength RC. Tower typology; out of MT competitive range.
D — Held US Design Studies & LCAs (concrete schemes, above-grade)
Each row is read from the held document. Floor-area basis and carbon scope differ by source and are stated per row. A design study is a designer's or researcher's scheme, not a built-and-measured building, except where noted. These are design points, not bands, so each spans the three intensity columns; where a study covers several heights, the values follow the Storeys order.
Source	Location	Building	Storeys	Intensity m³/m² GFA			Structural EC kg CO₂e/m²	Confidence	Basis & Notes
Source	Location	Building	Storeys	Design point(s)			Structural EC kg CO₂e/m²	Confidence	Basis & Notes
Puettmann et al. 2021, Sustainability 13:13987 (+ supplement, Table S4)	Pacific NW (the same design reused for the Northeast and Southeast)	Mixed use, RC frame + concrete core	8 / 12 / 18	0.31 / 0.30 / 0.31			226 / 281 / 239	★★	Conceptual design. One concrete design serves all three regions, so it is not seismically differentiated. EC is whole-building A1–A5 (structure plus walls), not structure only.
Liang et al. 2020, Wood and Fiber Science 52(2):217 — Framework RC alternative	Portland, OR	Mixed use, RC Type I-B	12	0.30			237	★★	Quantities from the building designer. EC covers structure and envelope, A1–A5. Chen et al. 2020 (Sustainability 12:4708) models the same building at 0.31.
University of Washington / Carbon Leadership Forum, prototype mass timber office models — material quantities (2018)	Seattle, WA	Office (real building), slab-band frame + RC shear walls, 3 parking levels below	8	0.46 (0.38 gravity only)			530	★★	Taken from the building's drawings, on above-grade GFA (102,400 ft², Table 15). EC covers structure, subgrade, curtain wall and roof, A1–A5. Internal report, not peer reviewed.
MIT Concrete Sustainability Hub 2011, Methods, Impacts, and Opportunities in the Concrete Building Life Cycle	Chicago / Phoenix	Office (DOE large-office prototype), flat slab + moment frame + 2 cores	12 + basement	0.27			192	★★	Table 8.12 quantities; 2,400 kg/m³ assumed to convert mass to volume. EC covers structure and shell, A1–A4 (Chicago).
Kumar et al. 2024, Data in Brief + Mendeley bill of materials	Generic US (SDC B)	Residential, RC flat slab + RC columns	8 / 12 / 18	0.43 / 0.39 / 0.39			—	★★	Quantities from an Athena Impact Estimator bill of materials. The paper's carbon results are not held.
WoodWorks / KPFF 2026, LCA of Prototypical Office Buildings (moderate- and high-seismic editions)	El Paso, TX (SDC C) / San Diego, CA (SDC D)	Office, PT flat slab + RC shear walls	12 + basement	—			180 / 315	★★	Structure only, stage A (Table 5-2). No quantities published. High seismic adds 75% to the concrete structure's carbon.
FEMA P-751 (2012), 2009 NEHRP Recommended Seismic Provisions: Design Examples, Ch. 7	Berkeley, CA (SDC D) / Honolulu, HI (SDC C)	Office, RC pan-joist floor + moment frames (+ special walls at Berkeley)	12 + basement	0.31 / 0.27			—	★★	One building designed for both sites (ASCE 7-05, ACI 318-08). Our take-off from the published member sizes: 12 suspended floors on above-grade GFA, within 5% of the example's storey weights. No carbon published. Also shown in section A2.

What the held data says. Measured Canadian CIP towers (conventionally reinforced, n=2) come in at 0.52–0.54 m³/m² at 11–20 storeys, beside the Vancouver estimate. Measured US West Coast towers (all post-tensioned, n=6) come in lower, median 0.36, and the held US design studies sit at 0.27–0.31 at 12–18 storeys. Per square metre, height adds little concrete: the floors are most of it and stay the same thickness; only the core and the lower columns grow. The estimator's table value for 13–18 st (0.48 → 0.53) is a Canadian reinforced-concrete calibration, now used only to read a whole-building override. Since 2026-10-27 the engine prices an itemised frame: the RC flat plate and columns it designs for the building, plus suite demising (and corridor) walls where the market casts them in concrete (the Interior concrete walls input), plus each city's own core. These data validate the calculated intensity; they are not a target to tune it to.

Held sources: Carbon Leadership Forum WBLCA Benchmark Study v2 dataset, github.com/Life-Cycle-Lab/wblca-benchmark-v2-data (buildings_metadata + full_lca_results, commit 5b641d2, 2025) | Puettmann et al. 2021 | Liang et al. 2020 | Chen et al. 2020 | UW / CLF material quantities report (2018) | MIT CSHub (2011) | Kumar et al. 2024 | WoodWorks / KPFF (July 2026). Sections A, B and C are engineering estimates. The documents earlier named for them (Altus, Turner & Townsend, Introba, MKA, CLF SE2050, Thornton Tomasetti, ARUP, WRAP/IStructE, CMHC, the Brock Commons study, Athena) are not held, and the Altus Cost Guide carries no intensity data. Sa(0.2): NBCC 2020 6th-generation hazard (SHM6), Site Class C, 2%/50 yr, as held in the app's data/ca/lateral-core-data.json (the NBC document itself is not held). All intensities: above-grade structure only, excludes foundations. m³/m² = m³ concrete placed per m² GFA.
Developer Compass is not affiliated with, endorsed by, licensed by or acting for the Carbon Leadership Forum, the University of Washington, MIT, WoodWorks, KPFF, LEVER Architecture, the USDA Forest Products Laboratory, SE 2050, or any other organisation named above. Source names are used for factual reference only and remain the trademarks of their respective owners.

Table 6bPodium Structural Grid — Concrete Intensity & Cost Basis

Grid / Slab Type	Intensity (m³/m² GBA)	Rate Mult	Mass (kg/m²/lvl)	Typical Span	Description
Standard (9 m grid)	0.35 m³/m²	×1.05	840 kg/m²	7–10 m	RC flat plate 275–300 mm. Retail/CRU 9 m bay. Most common podium grid. Sources: Altus 2026 CCG; Hanscomb 2024.
Long-span (12 m grid)	0.45 m³/m²	×1.15	1,080 kg/m²	10–14 m	Open commercial 12 m bay. RC flat plate 350–400 mm or PT 300 mm. Higher rebar density.
PT Flat Plate (12–15 m)	0.35 m³/m²	×1.35	840 kg/m²	12–16 m	Post-tensioned flat plate. Thinner slab, longer spans. Higher unit rate includes PT supply/stress. Altus PT premium $100–150/m³ over RC.

Intensity = m³ placed concrete per m² of podium GBA. Includes columns, flat plate slab, shear walls. Excludes foundations, MEP rough-in, envelope. The concrete rate model prices the podium slab on its grid\u2019s slab thickness (Table 7c); the grid\u2019s old rate multiplier now applies only to an unpriced PT grid. Sources: Altus 2026 CCG; Hanscomb Yardsticks 2024; a real-project benchmark held under NDA (project data, 2025); a 2025 Ontario supplier purchase order.

Table 6cCIP Concrete Intensity by Seismic Category, Wind & Building Size — measured, designed and the estimator (m³/m²)

Every US and Canadian cast-in-place concrete building in the CLF WBLCA Benchmark v2 dataset that passes the Table 6a screening (new construction, concrete floors, GFA recorded, superstructure above substructure, not a podium-only or light-frame-over-podium building), at every height: 46 buildings (40 US, 6 Canada). Cells hold few buildings: read them as bands. These data check the calculated intensity; they are not a target to tune it to.

Seismic category	Storeys	n	Measured, CLF v2 (m³/m²)			Estimator (m³/m²)		Notes
A — By seismic design category and height (above-grade CIP per unit of floor area)
Measured: superstructure cast-in-place concrete of every screened CLF building, all uses. The constructed-area column spreads it over parking and other area the GFA leaves out. Estimator: the engine’s own gravity frame plus each city’s designed core, residential, 15,000 m², at the storeys named, for the roster cities in that category (SDC from the ASCE 7-22 core database).
Seismic category	Storeys	n	Median, GFA	Range, GFA	Median, constructed area	Median	Range (cities)	Notes
A–B (low)	1–5 (estimator at 4)	3	0.63	0.55–0.68	0.63	0.33	0.33	Three non-residential buildings on conventionally reinforced floors (two education, one assembly); none residential.
A–B (low)	6–10 (estimator at 8)	5	0.45	0.22–0.58	0.41	0.36	0.36
A–B (low)	11–20 (estimator at 12 and 16)	1	0.33	0.33	0.33	0.39	0.38–0.40
A–B (low)	21+ (estimator at 20)	2	0.49	0.37–0.61	0.44	0.44	0.43–0.44
C (moderate)	1–5	1	0.38	0.38	0.38	—	—	One 2–5 storey lab (Washington). No roster city is SDC C; the FEMA P-751 SDC C design study is in Table 6a §A2.
D (high)	1–5 (estimator at 4)	12	0.43	0.12–0.72	0.36	0.34	0.33–0.35
D (high)	6–10 (estimator at 8)	8	0.40	0.26–0.53	0.36	0.43	0.36–0.44
D (high)	11–20 (estimator at 12 and 16)	7	0.38	0.31–0.55	0.32	0.49	0.38–0.61	Mostly PT residential and office in California, Oregon and Washington; one BC tower on RC floors. The estimator runs above the measured median here.
D (high)	21+ (estimator at 20)	2	0.85	0.71–1.00	0.52	0.54	0.43–0.66	Both carry parking decks in the superstructure that the GFA leaves out (CLF 196 Washington, 1 British Columbia); read the constructed-area figure.
E (very high)	1–5	2	0.60	0.37–0.82	0.35	—	—	Two California buildings: an office whose superstructure includes area outside its GFA (0.33 on constructed area), and a lab. No roster city is SDC E.
B — By the other drivers (measured, all heights; estimator where it has the dimension)
Same buildings as section A. Wind is the ASCE 7 basic wind speed each LCA recorded; the estimator’s wind is the city’s ASCE 7-22 Risk Category II speed.
Driver	Group	n	Measured, CLF v2 (m³/m²)			Estimator (m³/m²)		Notes
Driver	Group	n	Median, GFA	Range, GFA	Median, constructed area	Median	Range (cities)	Notes
Floor system	Post-tensioned	29	0.39	0.22–0.82	0.36	—	—	The largest single effect in the data.
Floor system	Conventionally reinforced (non-PT)	17	0.54	0.12–1.00	0.45	—	—	The estimator’s gravity frame is a Canadian RC calibration (Table 6a).
Floor system × seismic	PT, SDC A–B	5	0.41	0.22–0.54	0.36	—	—
Floor system × seismic	PT, SDC D	21	0.39	0.26–0.72	0.34	—	—	Like for like, the measured data show no seismic increase (PT, SDC D vs A–B). The estimator adds about 26% at 12 storeys.
Use	Residential / hotel	17	0.41	0.22–1.00	0.38	—	—
Use	Non-residential (office, lab, education, assembly)	29	0.44	0.12–0.82	0.40	—	—
Design wind speed	≤ 115 mph	20	0.42	0.12–1.00	0.38	0.38	0.38–0.55
Design wind speed	116–140 mph	17	0.40	0.22–0.68	0.37	0.38	0.38–0.53
Design wind speed	> 140 mph	5	0.43	0.32–0.45	0.41	0.38	0.38	Estimator at 12 storeys. Miami (170 mph, SDC A) gets the same minimum core as Houston and Boston: wind does not govern the core at this height.
Building size (GFA)	< 5,000 m²	11	0.44	0.12–0.72	0.37	0.40	0.40–0.56	Estimator at 12 storeys, 5,000 m².
Building size (GFA)	5,000–15,000 m²	13	0.45	0.26–0.78	0.40	0.38	0.38–0.55	Estimator at 12 storeys, 15,000 m².
Building size (GFA)	15,000–30,000 m²	13	0.42	0.33–1.00	0.40	—	—
Building size (GFA)	> 30,000 m²	9	0.39	0.22–0.71	0.38	0.36	0.36–0.51	Estimator at 12 storeys, 40,000 m².
C — Designed: NIST GCR 10-917-8 RC shear-wall archetypes, walls only, by height and seismic level
The 40 archetypes NIST designed to ASCE 7-05 and ACI 318-08 to test the FEMA P-695 method: two walls each way in a rectangular building-frame plan, sized to work the walls hard at each height. Each height keeps one wall geometry across seismic levels and changes only the reinforcement, so designed wall concrete does not change with seismic level; the base shear, the spare capacity and the steel do. Wall concrete = 4 walls × length × thickness × height ÷ floor area. Rebar = web steel (two curtains, both ways, as tabulated) plus boundary bars, no laps or hoops: a lower bound. Range = the high- and low-gravity variants. Estimator = its core concrete for the US cities at that S_DS (residential, 15,000 m², at 4, 8 and 12 storeys).
Storeys	Seismic level	Archetypes	Wall concrete m³/m²	Base shear V/W (g)	Shear stress (√f′c) · V_n/V_u	Wall rebar kg/m²	Estimator core m³/m²	Notes
1	Dmax (S_DS 1.0 g) special	1, 11	0.003	0.17	7.9 · 1.17–1.20	0.42	—	Walls are 0.1–0.2% of the floor plan: lateral concrete is negligible at one and two storeys.
1	Dmin (S_DS 0.5 g) special	6, 16	0.003	0.08	4.0 · 1.03	0.17	—
1	Cmax (S_DS 0.5 g) ordinary	21, 31	0.003	0.10	4.7 · 1.15	0.42	—
1	Cmin (S_DS 0.33 g) ordinary	26, 36	0.003	0.07	3.2 · 1.10	0.24	—
2	Dmax (S_DS 1.0 g) special	2, 12	0.005	0.17	7.9 · 1.17–1.20	0.82–0.84	—
2	Dmin (S_DS 0.5 g) special	7, 17	0.005	0.08	3.9 · 1.03	0.21–0.32	—
2	Cmax (S_DS 0.5 g) ordinary	22, 32	0.005	0.10	4.7 · 1.15	0.82	—
2	Cmin (S_DS 0.33 g) ordinary	27, 37	0.005	0.07	3.2 · 1.00	0.41	—
4	Dmax (S_DS 1.0 g) special	3, 13	0.017	0.17	4.3 · 1.10	1.56–1.95	0.019 (0.018–0.025)	Walls at their shear limit (V_n/V_u 1.1).
4	Dmin (S_DS 0.5 g) special	8, 18	0.017	0.06	1.7 · 2.00	0.77–0.87	0.012 (0.011–0.013)
4	Cmax (S_DS 0.5 g) ordinary	23, 33	0.017–0.039	0.08	2.0 · 1.05–1.30	0.74–1.27	0.012 (0.011–0.013)	The high-gravity variant uses a longer, thicker wall (41 ft × 16 in) than Dmax does.
4	Cmin (S_DS 0.33 g) ordinary	28, 38	0.017	0.05	1.3 · 2.00	0.74	0.009
8	Dmax (S_DS 1.0 g) special	4, 14	0.050	0.12	2.0 · 1.65	2.49–3.53	0.092 (0.086–0.097)	Spare shear capacity from here up: flexure and boundary steel govern.
8	Dmin (S_DS 0.5 g) special	9, 19	0.050	0.04	0.7 · 4.95	2.25	0.052 (0.046–0.059)
8	Cmax (S_DS 0.5 g) ordinary	24, 34	0.050	0.05	0.8 · 3.30	2.25	0.052 (0.046–0.059)
8	Cmin (S_DS 0.33 g) ordinary	29, 39	0.050	0.03	0.5–0.8 · 3.30–5.00	2.25	0.023
12	Dmax (S_DS 1.0 g) special	5, 15	0.077	0.09	1.5 · 2.10–2.13	3.20–3.82	0.162 (0.116–0.204)	Estimator cities at this level or above: Los Angeles, San Francisco, Seattle, Salt Lake City, San Diego, Hawai’i (S_DS 1.10–1.58, above the study’s 1.0).
12	Dmin (S_DS 0.5 g) special	10, 20	0.077	0.03	0.5 · 6.37–6.40	3.01	0.059 (0.052–0.066)	The same walls carry a third of Dmax’s base shear (V_n/V_u 6.4): not a minimum design for this level. Estimator cities: Portland, Sacramento.
12	Cmax (S_DS 0.5 g) ordinary	25, 35	0.052–0.077	0.03	0.6 · 4.25	2.35–3.01	0.059 (0.052–0.066)
12	Cmin (S_DS 0.33 g) ordinary	30, 40	0.077	0.02	0.4–0.6 · 4.25–6.40	3.01	0.028	Estimator city: Nashville (S_DS 0.36). Cities below S_DS 0.33 (SDC A–B) get the estimator’s minimum core, about the same as Nashville’s.

What it says. Floor system and use move concrete more than seismic category or wind: post-tensioned buildings carry about 27% less than conventionally reinforced ones, and no wind band stands out. Like for like (post-tensioned), high-seismic buildings carry no more concrete than low-seismic ones (median 0.39 vs 0.41 m³/m²). The estimator adds about 26% for SDC D at 12 storeys and up to 50% at 20 (San Francisco, Hawai’i, Los Angeles), all of it in the city core. Against the measured medians the estimator runs low on low-rise buildings (mostly non-residential in the data) and high on SDC D residential at 11–20 storeys (about 0.10 m³/m²: the comparator’s conventionally reinforced floor and the ACI 318-19 wall-shear amplification, see below). The designed archetypes (section C) agree: in an RC shear-wall building, high seismic changes the reinforcement and the spare capacity, not the wall concrete, and code-designed walls run 0.05–0.08 m³/m² at 8–12 storeys with shear capacity to spare even at S_DS 1.0. The estimator’s core for its high-seismic cities is about twice that at 12 storeys (0.16 median; 0.20 in Los Angeles and San Francisco), but its own core generator gives 0.075 on the study’s inputs: the difference is in the inputs, not the method. Three add up: a hotter hazard (S_DS up to 1.58 against 1.0, correct for ASCE 7-22); the ACI 318-19 §18.10.3 wall-shear amplification, which the study and almost all of the measured buildings predate and which roughly doubles the Los Angeles core; and the comparator’s conventionally reinforced floor, whose weight the core must also resist. On a post-tensioned floor the Los Angeles 12-storey total is about 0.35, beside the measured SDC D median of 0.39 (US core database check, 2026-10-21). A residential core also has openings the archetypes lack.
Held sources: CLF WBLCA Benchmark v2 dataset (buildings_metadata + full_lca_results, commit 5b641d2); per-building trace and scripts in the Source Register, §3.5 and §3.9. NIST GCR 10-917-8 (ATC-76-1), Evaluation of the FEMA P-695 Methodology for Quantification of Building Seismic Performance Factors, November 2010: Tables 4-3, 4-4 and B-3 to B-14 (held; Source Register §3.5a). Estimator: engine run 2026-10-21 on the US golden-master base (residential, gravity frame + designed core, above grade).
Developer Compass is not affiliated with, endorsed by, licensed by or acting for the Carbon Leadership Forum, the University of Washington, NIST or the Applied Technology Council. Source names are used for factual reference only.

Rate — what it costs in place

Table 7Concrete Frame Rate by Market — the slider seed, from the concrete rate model ($/m³)

The rate the Concrete slider is seeded at in each market: the RC FRAME (flat plate + columns, 35/40 MPa) all-in, at the concrete rate model's reference building (12 storeys, 1,250 m² plates, no winter), with frame rebar at the reference $/kg. It is built from first principles: that market's ready-mix price and crew packages (carpenter, labourer, cement finisher), the crew-hours and form material per m² of contact, shoring, placing, finishing and curing, the inefficiencies and the concrete trade's overhead and profit (Table 7c). Every other element (core walls, parkade, podium, transfer, foundation) is priced from it by the same model, so no element shares the frame's rate any more. Low/High = crews and ready-mix ±12%. Excludes PT, HST/GST/QST.
Avg column colour: the market's place in this table (thirds) — dearer concrete markets at the top. A colour is a ranking, not a verdict on mass timber.

Market	Province	Low	Avg	High	Confidence	2026 Trend	Notes

Sources: see Table 7c (every parameter, its basis and status). Crew packages from the published ICI collective agreements and wage schedules held in the Source Register §3.10; ready-mix from held price evidence; relative element costs checked against an independent QS cost model (Los Angeles, 2010) and the frame level against a Halifax QS Class D estimate (June 2026). CAD 2026 in Canada, USD 2026 in the US.

Table 7cConcrete Rate Model — first-principles $/m³ by element (DATA.concreteRateModel, model/concrete-rates.mjs)

Each element is built the way an estimator prices concrete: its parts (slab, columns, edges, walls, mat) each priced as ready-mix + forming (crew-hours per m² of contact × the carpenter package + form material) + shoring + placing + finishing + curing; then inefficiencies (height, plate size, the first floors' learning, winter productivity, sundries) and the concrete trade's overhead and profit. Rebar is separate, on each element's own tonnage. The first table is THIS estimate; the second lists the parameters, each with its basis.

Parameter	Value	Units	Basis · status

Table 7bPost-Tensioned Floors — the one PT model (DATA.ptParams, model/pt-floor.mjs)

One model prices every post-tensioned slab in the estimate: the concrete scheme's floors (Floor system, Concrete inputs), the podium's PT grid and the PT transfer slab. The slab is designed on the building's own loads and grid (span/depth, fire, punching with the precompression credit, long-term deflection on the load the tendons do not balance); strand follows from load balancing; mild steel is what the code and strength still ask for. It is measured against the RC flat plate the concrete benchmark assumes, and only the difference is used. Every rate and assumption below is an ASSUMPTION until a PT subcontractor, GC or structural engineer supplies it.

Parameter	Value	Units	Status · who to ask

Substructure & transfers

Table 8Foundation Calculation Parameters — DATA.foundationParams

Parameter	Value	Units	Notes & Source
Rebar rate, placed	—	$/kg	Supply + place.
Excavation / Shoring / Waterproofing Base ($/m² GFA)
S1 — Good soil	—	$/m² GFA	Dense till/gravel/rock. Minimal shoring.
S2 — Moderate	—	$/m² GFA	Compact sand/stiff clay. Light shoring.
S3 — Poor	—	$/m² GFA	Soft clay/loose silt. Sheet piling likely.
S4 — Very poor	—	$/m² GFA	Peat/fill. Deep shoring required.
Rebar Density by Foundation Type (kg/m³ concrete)
Spread footings	—	kg/m³	Lightly loaded spread footings. Altus benchmark.
Raft slab (low pressure)	—	kg/m³	Raft at q ≤ 0.5 × q_allow.
Raft slab (high pressure)	—	kg/m³	Raft at q → q_allow. Scales linearly between lo and hi.
Pile caps	—	kg/m³	Heavily reinforced pile caps. MTO 2024.
Geometry
Grade beam section	—	mm × mm	Width × depth. Standard grade beam connecting pile caps.
Pile cap thickness factor	—	× pile diameter	capThk = factor × pile diameter. Min 500 mm.
Pile cap plan factor	—	× pile diameter	capPlan side = factor × pile diameter (square cap).
Raft Slab Thickness
Base thickness	—	mm	Minimum raft thickness at zero contact pressure.
Pressure range	—	mm added	Additional thickness from base to q_allow (linear). raft_thk = base + pressureRatio × range.
Schedule Extras (wks added vs S1 spread baseline)
Spread footings	—	wks	Baseline. Note: soil class adds its own schedExtra on top.
Raft slab	—	wks	Extra forming + curing time vs spread footings.
Piles	—	wks	Piling rig mobilization + pile installation duration.

All values read from DATA.foundationParams — single source of truth. Edit DATA object to update. Sources: Altus 2026 CCG Div 03; MTO Geotechnical Design Standards 2024 †; a real-project benchmark held under NDA (project data, 2025). Div 31–32 excavation and foundation unit rates are engineering estimates, not extracted from a published unit-rate database. († not re-verified against the primary document for this release.)

Table 9Transfer Slab Types — Cost & Schedule by Configuration

Type	Thickness	Rebar Density	Cost ($/m² footprint)	Mass (kg/m² footprint)	Schedule (wks)	Use Case
Light — MT / steel tower	600 mm	200–250 kg/m³	$950/m²	1,440 kg/m²	2.5 wks	MT or steel tower above. Standard for mass timber on podium. Minimal column offset.
Standard — concrete tower	750 mm	250–300 kg/m³	$1,200/m²	1,800 kg/m²	3.0 wks	CIP concrete tower above. Standard flat-plate tower grid change.
Heavy — large grid offset	900–1,000 mm	300–400 kg/m³	$1,600/m²	2,400 kg/m²	3.5 wks	Column offset > 6 m, or PT transfer. Structural engineer required. Altus 2025 range $1,400–$1,900/m².

Cost per m² of building footprint (not GFA). Schedule = critical path weeks for forming, pouring, stripping, and curing the transfer slab only — add to podium level weeks. Transfer slab mass included in foundation load calculation. Sources: Altus 2026 CCG; Hanscomb Yardsticks 2024 (transfer slab chapter); an engineered real-project benchmark held under NDA (structural drawings and preconstruction report, 2025).

Scope & carbon

Table 10Gypsum / Finish Allowance for Like-for-Like Scope ($/m²)

Applied to concrete to make comparable to exposed MT structure. Source: Spreadsheet "Concrete" rows 22–24

Table 10aLCA Embodied Carbon Benchmarks — Concrete Structure (kg CO&sub2;e/m² GFA)

Structural embodied carbon from held real-project data and design studies. The boundary is stated per row: the CLF dataset reports A1-A3, A4, B4-B5, C2-C4 and D, with no A5. Use columns together: kg CO₂e/m² ÷ m³/m² = implied carbon per m³ of concrete. It includes rebar and PT, so it runs higher than concrete alone. Confidence: ★★★★ = held real-project data, n ≥ 10 ★★★ = held real-project data, n 4–9 ★★ = held data, n ≤ 3, or a design study Est. = Developer Compass engineering estimate, no held source.

A — Project-Level LCA Data (CLF WBLCA Benchmark v2, real buildings)

Superstructure (floors, roof, stairs, frame, core walls), all materials, A1–A4. Ranges are min–max with the median in brackets. Every cohort is under 10 projects, so read it as a band. Each row lists its CLF project_index.

Source / Project	Building Type	Storeys	Location	Structural EC (kg CO₂e/m²)	m³/m² implied	Boundary	Confidence	Notes
CLF WBLCA Benchmark v2 — Canadian high-rise residential (n=2)	Multifamily over podium, RC flat plate	11–20	British Columbia + one unstated province	240–405	0.52–0.54	A1–A4, super	★★	Both count parking in constructed area; spread over that area the intensity falls about 20%. CLF project_index 171, 247.
CLF WBLCA Benchmark v2 — US West Coast mid-rise (n=6)	Multifamily residential, CIP + PT flat plate	6–10	California / Washington (SDC D)	154–298 (233)	0.26–0.53 (0.41)	A1–A4, super	★★★	Real project LCAs with designer quantity take-offs. CLF project_index 58, 60, 71, 81, 97, 170.
CLF WBLCA Benchmark v2 — US West Coast high-rise (n=3)	Residential / hotel, PT flat plate	11–20	California / Oregon (SDC D)	236–251	0.31–0.41 (0.38)	A1–A4, super	★★	EC from 2 projects: 139 carries no rebar and is left out. Both Oregon projects model lightweight concrete throughout. CLF project_index 65, 139, 147.
CLF WBLCA Benchmark v2 — Washington podium tower (n=1)	Multifamily over CIP podium, PT	21+	Washington (SDC D)	571	0.71	A1–A4, super	★★	Single project, above the 12–18 band. Parking decks are counted in the superstructure but not in GFA, which inflates both per-GFA figures. CLF project_index 196.
CLF WBLCA Benchmark v2 — US low-seismic high-rise (n=2)	Multifamily residential, CIP	16–21+	New York / Texas (SDC A–B)	241–301	0.33–0.37	A1–A4, super	★★	Lower intensity than the West Coast but similar EC, so the modelled mixes carry more carbon per m³. The Texas tower (23) sits on a steel podium. CLF project_index 23, 110.

B — Held Published Studies & Databases

Source	Scope	Structural EC (kg CO₂e/m²)	m³/m² range	Year	Confidence	Notes
CLF WBLCA Benchmark v2 dataset — US CIP concrete, all uses	US, 6+ st, n=20 (EC n=18); superstructure A1–A4	230–264 (247)	0.34–0.47 (0.40)	2025	★★★★	Interquartile range, median in brackets. n is 10 or more, so the median can be read as a point. Office, lab, education and residential.
CLF WBLCA Benchmark v2 dataset — US CIP concrete, residential	US multifamily + hotel, 6+ st, n=12 (EC n=11); superstructure A1–A4	230–280 (243)	0.33–0.42 (0.39)	2025	★★★★	Interquartile range, median in brackets. 10 of the 12 are West Coast (SDC D), so this is a West Coast figure in practice.
SE 2050 Commitment database — summary in STRUCTURE magazine (2 Dec 2024)	Structural systems, upfront carbon (A1–A5), 241 projects, mostly US; shown as median / mean / 80th percentile	234 / 270 / 350	—	2024	★★★	All structural systems pooled (concrete, steel, timber), so not concrete-specific. The authors say the spread is too wide to set benchmarks; P80 is their proposed upper limit.
WoodWorks / KPFF, LCA of Prototypical Office Buildings, 12-st PT flat-slab office	Structure only, stage A; moderate (SDC C, El Paso) / high seismic (SDC D, San Diego)	180 / 315	—	2026	★★	Table 5-2. No quantities published. High seismic adds 75% to the concrete structure's carbon.
Puettmann et al., Sustainability 13:13987 — 8 / 12 / 18-st mixed use, concrete scheme	Whole building (structure + walls), A1–A5; Pacific NW	226 / 281 / 239	0.31 / 0.30 / 0.31	2021	★★	Design study. Northeast and Southeast reuse the same concrete design.
Liang et al., Wood and Fiber Science 52(2):217 — Framework RC alternative, Portland	Structure + envelope, A1–A5; 12 st	237	0.30	2020	★★	Quantities from the building designer.
UW / Carbon Leadership Forum — material quantities report, real Seattle office	Structure + subgrade + curtain wall + roof, A1–A5; 8 st + 3 below	530	0.46	2018	★★	From the drawings, on above-grade GFA. The wide scope (subgrade and curtain wall) explains the high EC.
MIT Concrete Sustainability Hub — DOE large-office prototype	Structure + shell, A1–A4; 12 st + basement, Chicago	192	0.27	2011	★★	2,400 kg/m³ assumed to convert mass to volume.

C — Implied Concrete Carbon Intensity Cross-Check (kg CO₂e/m³)

Derived from: Structural EC (kg CO₂e/m²) ÷ Structural intensity (m³/m²). Validates whether EC and intensity data are internally consistent. Compare to EPD values for your specified concrete mix.

Concrete Mix / Context	Implied kg CO₂e/m³	GHG Protocol / EPD Source	SCM Content	Notes
Standard 30 MPa OPC — Canada average	310–370	Estimate — EPD not held	0–10% fly ash	Baseline for estimator default. High carbon — no SCMs.
30 MPa with 20–25% fly ash (FA) — BC / AB	240–290	Estimate — EPD not held	20–25% FA	Common Lafarge/Holcim standard mix; available most BC/AB markets. ~20% reduction vs. OPC.
35 MPa with 30% GGBS (slag) — ON / QC	210–260	Estimate — EPD not held	30% GGBS	Slag available in ON/QC via St. Marys, Lafarge. Good strength gain; ~30% carbon reduction.
35 MPa with 40% GGBS — coastal BC premium	180–230	Estimate — EPD not held	40% GGBS	Best-practice low-carbon mix; premium ~+$20–40/m³; available Vancouver/Victoria. Specify for ZCB projects.
40 MPa with 10% silica fume — seismic BC	290–340	Estimate — EPD not held	5–10% SF	Higher strength → more cement content; silica fume improves durability but adds cost +$30–50/m³.
Measured — CLF WBLCA v2, US CIP 6+ st (normal-weight ready-mix only)	357–439 (400)	CLF WBLCA Benchmark v2 (held)	Varies	Concrete only, A1–A3: interquartile range of 17 projects, median in brackets, from the designers' EPD selections. Dividing all superstructure carbon (incl. rebar and PT) by CIP volume gives a median about 1.6× this.
Estimator material factors (30 / 35 MPa)	295 / 340	Engine DATA.lcaBenchmarks; the EPDs named there are not held	~15% SCM avg	Used in CA and US mode alike, and below the measured US median above. Use a project EPD where you have one.

Held sources: Carbon Leadership Forum WBLCA Benchmark Study v2 dataset, github.com/Life-Cycle-Lab/wblca-benchmark-v2-data (buildings_metadata + full_lca_results, commit 5b641d2, 2025) | SE 2050, STRUCTURE magazine (Dec 2024) | WoodWorks / KPFF (July 2026) | Puettmann et al. 2021 | Liang et al. 2020 | UW / CLF material quantities report (2018) | MIT CSHub (2011). The Canadian rows earlier shown here (Athena, RDH, FPInnovations, CWC / WoodWorks Dartmouth, BC Housing, Entuitive, Morrison Hershfield, EC3, CAGBC, Hanscomb, NRCan) were removed because no copy of those documents is held; they return when the documents are filed in the Source Register. Section C mix ranges are estimates. All carbon values: kg CO₂e, GWP100.
Developer Compass is not affiliated with, endorsed by, licensed by or acting for the Carbon Leadership Forum, the University of Washington, MIT, WoodWorks, KPFF, LEVER Architecture, the USDA Forest Products Laboratory, SE 2050, or any other organisation named above. Source names are used for factual reference only and remain the trademarks of their respective owners.

Table 11Steel Intensity — Used by the Estimator, with Published Benchmarks (kg/m²)

Building type	Storeys	Low	Mid	High

Estimator rows: DATA.steelIntensity, frame steel per gross floor area (beams, columns, bracing). Deck and connections are priced separately (Table 13). Low = bottom of the typology’s storey range, High = top; the estimator interpolates by storey, and the Steel Intensity Override replaces it for one project. Benchmark rows check these values; they are never a target to tune them to. Benchmarks: CISC benchmarks; spreadsheet “Steel” columns O–T; report Section 2.4.2.

Table 12Steel Rate by Market — Supply + Fab, Erection, Installed ($/kg)

Market	Supply + fab	Erection % of supply + fab	Installed	Installed range	Installed vs baseline	Source
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Supply + fab (mill steel, detailing, shop fabrication, delivery) is the Steel Price slider; erection is the Erection / Install Factor slider. Installed = supply + fab × (1 + erection %). Both are set from this table when the location changes and stay overrideable. Excludes deck, fire protection, supplementary connections and drywall (Table 13). Canadian rows: erection is the 25% default in every market. Sources: Altus 2026 CCG Div 05; CISC 2024 Canadian Structural Steel Market Survey †; T&T CMI Q4 2025 †. Markets without Altus coverage use derived ratios to Vancouver, not a third-party index. († not re-verified against the primary document for this release.)

Table 13Add-ons for Like-for-Like Comparison, and the Fire Rating the Frame Needs ($/m² of floor)

Scope item	Low	High	Typical	Used in estimator	Basis

“Used in estimator” is the live slider value in the Structural Steel panel. The estimator prices fire protection as one rate, whatever the rating. Source: spreadsheet “Steel” rows 24–26; report Section 2.4.4.

Table 14This Building’s Steel Structure — Cost Build-up from the Estimator

Line	How it is priced	Cost
Run an estimate to fill this table.

Read from the current estimate: the steel system’s structural base, before the oil and carbon adjustments. It replaces the old price and install-factor matrices, which priced steel outside the estimator at fixed rates.

Table 15Oil Price Impact on Structural Cost ($/m² delta from $60/bbl baseline)

Oil Price	Mass Timber	Concrete	Steel

This building’s structural line, crude moved from the $60/bbl baseline with carbon held at $0. Each cost component moves by its own measured elasticity to WTI crude: run an estimate to list them. Elasticity = the long-run response of the component’s US producer price index to WTI: the same year’s plus the following year’s effect (delivered ready-mix picks fuel up about a year late), Jan 2000 – Sep 2026 with 2020–22 left out, controlling for industrial production (BLS producer price indexes, EIA WTI, EIA diesel and Federal Reserve industrial production, all via FRED). The 2020–22 COVID lumber spike and oil rebound fit engineered wood at 0.13 when included and 0.00 without. Installation labour is held at 0. Cores and foundations are not adjusted. US indices are used in both countries.

Table 16Carbon Price Impact on Structural Cost ($/m² delta from $0/tonne baseline)

Carbon Price	Mass Timber	Concrete	Steel

This building’s structural line at each carbon price, crude at the baseline. Carbon cost = the structure’s own fossil A1–A3 carbon × the price × a pass-through of 100% (100% = the whole price reaches the material; output-based pricing and free allowances pass through less). The carbon is this estimate’s own take-off on the estimator’s material factors (Table 10a, section C, and the gypsum board factor): run an estimate to list it. Carbon stored in the timber earns nothing: these prices tax emissions, and none credits storage. Cores and foundations are not adjusted. Consumer carbon tax eliminated BC Apr 2025. Industrial emitters subject to output-based pricing. $110/t row reflects projected industrial emitter price by 2026.

Table 20Full Construction Cost Stack Benchmarks — Canadian Mid-Rise Residential ($/m² GFA)

Trade / Line Item	Low	Mid (default)	High	% of hard cost	MT differential	Source
Below Grade
Foundations	$120	$180	$280	4–7%	Derived from load ratio (MT ~30–45% lighter than CO)	Altus 2025; derived via structural weight
Superstructure
Structural system	(see Tables 1–13)			10–18%	See structural estimator	Whirlwind Consultants / Altus 2025
Fire protection / encapsulation	(system-specific)			1–4%	MT: encap slider; CO: gypsum finish; ST: fireproofing+deck	Estimator
Core / lateral system	3%	5%	8%	3–8%	Same % for all systems; concrete core typical	Whirlwind Consultants project data
Enclosure
Envelope / facade	$350/m² facade	$1,100/m² facade	$1,800/m² facade	12–18%	Derived from facade area; Altus 2025 glass/glazing −15–20% in 2025	Altus 2025
Mechanical, Electrical & Plumbing
Mechanical (HVAC)	$280	$380	$520	9–13%	MT −5% (prefab sequencing, less ceiling congestion); Altus 2025 +10% YoY	Altus 2025 Canadian Cost Guide
Electrical	$120	$175	$250	4–6%	Same all systems; Altus 2025 +5% YoY electrical materials	Altus 2025 / StatsCan BCPI Q4 2025
Plumbing	$100	$165	$230	3–5%	Same all systems; StatsCan BCPI +4.2% YoY plumbing	StatsCan BCPI Q4 2025
Conveying (elevators)	$50	$95	$180	2–4%	Same all systems; Altus 2025 +2.4% YoY conveying equipment	Altus 2025
Interior Finishes
Ceiling drywall	$80	$120	$175	2–4%	MT: reduced by encapsulation % (exposed ceilings = no drywall)	Whirlwind Consultants project data
Acoustic topping (MT only)	$0	$48	$58	0–2%	MT only; 3 types: dry screed $38, light screed $48, regular screed $58/m²	Industry standard; see Table 24b below
Other finishes (flooring, cabinets, fixtures)	$300	$520	$850	12–18%	Same all systems	Altus 2025 residential mid-rise
Soft Costs
GC / General conditions	8%	12%	18%	8–18%	From Estimator gcPct slider	Industry standard
Consultants (A+E, PM, spec)	6%	10%	15%	6–15%	Same all systems	Whirlwind Consultants / industry standard
Contingency	2%	5%	12%	2–12%	Same all systems	Industry standard
Permits & development charges	2%	5%	8%	2–8%	Same all systems; varies widely by municipality	Industry standard

Sources: Altus Group 2026 Canadian Cost Guide (6,200+ projects, C$521B collective value); Statistics Canada Building Construction Price Index Q4 2025; Whirlwind Consultants project database. All rates: CAD, mid-rise residential context, Vancouver/Metro BC basis unless noted. Altus 2025 notable trends: mechanical +10% YoY, electrical +5% YoY, plumbing +4.2% YoY (StatsCan), conveying +2.4% YoY, glass/glazing −15–20%.

Table 21MT Acoustic Topping Types — Load & Cost Reference

Type	Description	Added Dead Load (kN/m²)	$/m² floor	Impact on MT structure	Typical use

Added dead load is applied to the MT structural load calculation in the cost stack foundation derivation. For concrete and steel systems, the slab weight is already embedded in the structural intensity benchmark — no separate topping is required. STC = Sound Transmission Class; IIC = Impact Insulation Class. NBC 2020 residential requirement: STC ≥ 50, IIC ≥ 50 between suites.

Table 22Market Cost Index — MEP, Finishes & Envelope (absolute multiplier on base; loads the slider per city)

Market	MEP & Finishes CCI	Envelope CCI	Steel factor 1−labourFrac×(1−cci)	Mech adj. $/m²	Elec adj. $/m²	Finishes adj. $/m²	Steel adj. $/kg	Envelope adj. $/m² facade	Source
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CCI factors applied automatically when location is changed. MEP/finishes/conveying/drywall use CCI. Envelope uses the separate env factor (material-heavier, less labour-sensitive). Steel uses steelFac = 1 − labourFrac × (1 − cci) where labourFrac = DATA.steelAdjParams.labourFrac (40% erection labour). All values relative to Vancouver = 1.00. Sources: Altus Group 2026 Canadian Cost Guide, p.5 Condominiums/Apartments ≤12 storeys (verified against the primary document); Turner & Townsend CMI Q4 2025 †; CISC 2024 erection cost survey †. The nine Altus-covered markets are benchmarked directly; Victoria, Kelowna, Saskatoon, Regina, London ON, Québec City and Moncton have no Altus coverage and use derived ratios to Vancouver — engineering judgment, not a third-party cost index. († not re-verified for this release.)

Table 23Parkade, Encapsulation & Conveying Parameters — DATA reference

Parameter	Value	Units / Formula	Source & Notes
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Parkade values from DATA.parkadeParams; encapsulation from DATA.encapParams; concrete quote allowances from DATA.concQuoteAllowance; conveying height factors from DATA.conveyingHeightFactors; steel adjustment from DATA.steelAdjParams. All single source of truth.

Table 24Schedule Base Superstructure Weeks by Typology — DATA.scheduleWeeks

Building Typology	MT (wks)	CO (wks)	ST (wks)	CO−MT saved	CO−ST saved
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Base superstructure weeks — before soil class adjustment, core system penalty, or parkade/podium schedule adder. Total project schedule adds foundation, envelope, MEP, and interior phases. Sources: a real-project benchmark held under NDA (preconstruction data, 2025); Whirlwind Consultants project database; Altus 2025 schedule benchmarks.

Table 26Core / Lateral System Intensity by City

Gravity frame the core serves:

Table 27MT Core System — Schedule & Cost Impacts ✎ Editable — all calculations update on change

Core schedule is modelled as a separate Gantt phase. Wks/floor and lead floors control when superstructure can start. Parallel cores run alongside gravity framing (no delay). Leading cores must build ahead. Edit values directly — changes propagate to Gantt, schedule savings, cashflow, and NPV.

Cost = lateral intensity (m³/m² or kg/m²) × seismic weight ratio × √(GFA/3,000 m²) × material price × (1 + install premium %). Install premium covers formwork, connections, embedments, labour.

Core System	Wks/Floor editable	Lead (floors) editable	Parallel?	Install Premium % editable	Deposit Lead wks editable	Deposit % editable	Notes editable	Governs for

⚠ CLT PBSD Rd=3.0 is research-based — not a codified NBCC 2020 SFRS. Do not use for permit submissions.
Parallel cores (CLT, CBF) run alongside gravity framing — no delay. Leading cores (CIP, precast) must build ahead before floor erection begins. Wks/floor and lead floors are editable and sync to the Schedule Parameters tab.

Table 28Seismic Reference Weights — DATA.seismicWeights & Core Scaling

Structural System	Reference Weight (kN)	Reference GFA (m²)	Weight/m² (kN/m²)	Notes
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Used to scale core/lateral intensity from the 3,000 m² NBCC 2020 EFP reference building to the actual project. coreIntensity_scaled = intensity × √(GFA/3000) × (actualWeight / referenceWeight). Reference building: 15×25 m plan, 8 storeys, 3.5 m f-f, Site Class D. Sources: NBCC 2020 EFP analysis; NRC seismic design guide; Whirlwind Consultants structural database.

LiveLife Cycle Assessment — Embodied Carbon Comparison

Class D ROM embodied carbon comparison for the current building configuration. Values update live from material volumes, intensities, and LCA benchmarks in DATA.lcaBenchmarks. Scope A1-A5 (cradle to practical completion). Biogenic carbon credit shown separately for transparency.

SensitivityTornado Chart — moved to the Configuration tab

The tornado now sits on the Configuration tab, directly above Cost Uncertainty & Range, so the driver ranking is read alongside the inputs that produce it.

Assumptions AuditAdjustments from Default — Conservatism Tracker

Lists every tracked input currently set away from its app default, flagged as favourable or conservative toward the MT business case. Helps show a reviewer how defensible the current run is and the net effect of the deviations.

Compares current inputs to the app’s shipped defaults. “Conservative” means the change makes the MT case harder (lower uplift, slower schedule, smaller MEP saving, etc.); “favourable” means the opposite.

Published cost studies the estimator is checked against — validation only, never an input. A mass-timber premium or a whole-building cost is something the estimator calculates; these studies sit here so a result can be compared with a real one.

LiveCalculations Audit

All major intermediate values from the current configuration. Updates live when any input changes. Use this to verify calculation logic, trace quantities, and check that changes propagate correctly. No hidden values exist outside this table and the DATA object.

Construction Schedule — Phase Gantt

Live — updates with Estimator inputs. All durations in structural on-site weeks. Overlaps reflect prefabrication and crew sequencing logic. Drag the right edge of a bar to make that phase shorter or longer: the Schedule Dynamics inputs below move to match (double-click a bar to jump to them).

Typology

—

Storeys

—

Floor Area

—

m²

MT Volume

—

m³

Concrete Volume

—

m³

Steel Mass

—

Intensity

—

Foundations

Superstructure

Envelope / Enclosure

MEP Rough-in

Interiors / Finishes

Mass Timber

Concrete

Structural Steel

Pre-design → occupancy one timeline · wk 0 = concrete ground break · hatched = design (fees paid)

Mass Timber

—

weeks on-site

vs. longest—

Est. $ saved/m²—

+ extra pre-design—

Inception→occupancy—

Concrete

—

weeks on-site

vs. longest—

Est. $ saved/m²—

+ extra pre-design—

Inception→occupancy—

Structural Steel

—

weeks on-site

vs. longest—

Est. $ saved/m²—

+ extra pre-design—

Inception→occupancy—

MT Schedule Parity Analysis

A — Cost Parity (Net All-In)

What MT erection pace is needed so that Net All-In /m² after schedule savings = CIP Concrete?
Accounts for full cost stack + GC/financing savings. Ignores long-term income.

Run estimator to calculate…

B — NPV Parity (Long-Term)

What MT erection pace is needed so that Total NPV (construction cost + PV income advantage) = CIP Concrete?
Requires rental premium or occupancy uplift to be set in Financial Estimates.

Run estimator to calculate…

Solver uses binary search on the MT Erection Schedule slider (56–222% range) to find the breakeven pace. Click Apply to set the slider and re-render. Parity values update automatically when inputs change.

Schedule Dynamics

Table 25Schedule Dynamics — All Variables Exposed

Every number that drives the schedule. No hidden constants in code — all inputs here feed directly into phase calculations. Changes update both the Estimator and the Schedule Gantt immediately. Dragging a Gantt bar writes here too: the inputs it moved flash and turn blue, and the change can be undone from the note that appears.

Parameter

Mass Timber

Concrete

Steel

Notes & formula role

Geometry

Perimeter factor

×(all systems)

Facade perimeter = 4 × √(area/storeys) × this factor. Accounts for non-square footprints. Square = 1.0, irregular = 1.15–1.30.

Floor-to-floor height

m(all systems)

Facade m² = perimeter × storeys × this height. Residential typically 3.0–3.3 m, office 3.5–4.5 m.

Pre-Construction Design & Procurement

Design + procurement lead

wks

Extra up-front design + procurement beyond the construction baseline. MT typically needs more (connection/DfMA design, LOD 400 fab models, fabricator design-assist, timber slot booking): ~4–12 wks. Steel: shop drawings + mill order ~2–8 wks. Netted against construction-time savings to give inception-to-occupancy.

Up-front design cost

$/m²

Design-assist fees, LOD 400 modelling, fire/peer review, early-engagement engineering. Added to the system’s construction cost (spent at project start, so it carries the full discount weight in NPV/IRR). MT ~$10–40/m².

Planning time effect

Delays occupancy (additive) Overlaps entitlement (absorbed)

Additive: the design lead pushes first occupancy later (reduces early-occupancy benefit, delays the income cash flows), less whatever an earlier pre-design start (below) absorbs. Absorbed: planning overlaps land entitlement/rezoning, so it adds cost but not occupancy delay, and design starts at least the lead ahead of concrete. Cost premium applies in both modes.

Baseline pre-design

wksbefore ground break (concrete reference, no lead)

How long design (architect, engineers, permit drawings) runs before ground break on the concrete build. Every system’s pre-design starts from here; leads and early starts add to it. Sets when design fees begin in the Table 24 cashflow.

Pre-design starts ahead of concrete

wks

reference

wks

How many weeks before the concrete alternative’s design starts this system’s design team is engaged: MT design-assist with the fabricator, early DfMA / LOD 400 modelling, timber slot booking. Design fees start flowing from that week, so the money goes out sooner (Table 24 cashflow, sales IRR, capital velocity). An early start absorbs the design lead first: in additive mode ground break slips only by the lead it doesn’t cover. Starting sooner than the lead needs never pulls ground break ahead of concrete’s. Default: MT starts 3 wks ahead.

Design fees paid before ground break

Share of the consultants line paid evenly from design start to ground break; the rest is paid over construction (site reviews, certification). The up-front design cost above is paid entirely before ground break. Raise MT where its design is front-loaded (connection and fabrication models finished before the shop starts).

Design starts

–

Live. Weeks before each system’s own ground break, and against concrete: how far ahead the design starts and how far ground break slips. Drawn in the pre-construction strip under the Gantt.

Site Works & Excavation

–

Gantt phase total — live

Site works base (wks)

wkshoarding, temp services, grading, servicing

Minimum site prep regardless of building size: hoarding, temp power/water, site office, survey, erosion control, utility connections.

Excavation per parkade lvl

wks/lvlbulk dig + shoring per ~3.5 m depth

Each parkade level adds ~3.5 m of excavation depth. Includes: bulk excavation, shoring/lagging installation (or soldier pile), dewatering staging, and soil trucking. 2 wks/lvl typical; 3+ for rock or high water table.

Footprint scale (wks / 500 m²)

wksper 500 m² footprint above 1,000 m²

Larger footprints take longer to excavate, shore, and service. +1 wk per 500 m² above a 1,000 m² threshold.

Calculated site works

6wks

= base + (parkade lvls × wks/lvl) + max(0, (footprint - 1,000) / 500) × fp scale. Override below if site conditions differ.

Override site works

Manual override

Check to override the calculated duration with a manual value. Use for prepared sites (0 wks), complex urban infill, or known site conditions.

Foundations (weeks)

–

Gantt phase total — live

Base foundation weeks

wks

Starting foundation duration for this typology (concrete = reference). Scaled by structural load ratio: found_wks = base × (total_load / CO_load).

Minimum foundation weeks

wks

Floor on foundation duration regardless of load ratio. Mobilisation, shoring, waterproofing, and cure time don't compress with lighter structure.

Super starts at (% of found)

%(all systems)

Superstructure begins once this % of foundations is complete. Concurrent excavation/pour sequencing allows early start. 70% = typical.

Structural density (kg/m³)

kg/m³

from intensity

Used to convert structural volume to mass for foundation load calculation. Steel mass comes directly from intensity (kg/m²). Total load = struct_mass + floor_load.

Core Construction (MT & Steel only)

–

Gantt phase total — live

Core wks per floor

wks

n/a (in pour cycle)

wks

Time per floor for core construction. CIP concrete core: ~1.0–1.5 wks (form, pour, strip, cure). Precast: ~0.5 wks. CLT core: ~0.4 wks (erected with gravity). Steel CBF: 0 (parallel with frame). CIP concrete buildings: core is part of the pour cycle, no separate phase. Auto-set from core system selection; override here.

Core lead (floors ahead)

n/a

How many floors the core must lead gravity framing by. CIP core: 3 fl (formwork + reshoring + cure). Precast: 1 fl. CLT/CBF: 0 (parallel). Floor erection cannot overtake core. If core is slower than floor cycle, core constrains overall pace.

Core starts at (% of found)

%(MT & ST only)

Core construction begins once this % of foundations is complete. Should be ≤ Super start % to ensure core can lead. 70% typical: core pile cap / base slab done. CIP concrete buildings: core is in the pour cycle, this doesn't apply.

Superstructure

–

Gantt phase total — live

Crew throughput (vol/wk)

m³

Volume/mass placed per week. 40% weight in superstructure duration. Vol component = material_vol / crew_rate. MT value is driven by the erection schedule slider below.

MT Schedule Presets

MT Erection Schedule

100% — Norm

Erection pace as % of normal. 100% = 180 m²/floor area per day (5-day week). Slide right to model accelerated crews or pre-assembly; slide left for complex sites. Converts to m³/wk using current MT intensity, then updates Crew Throughput above.

Floor cycle (wks/floor)

wks

Weeks per floor. 60% weight in superstructure duration. CIP concrete: Vancouver mid-rise benchmark 0.6–0.7 floors/wk with standard form-cycle and parallel MEP rough-in (5–6 working day form/pour/strip cycle). Default 0.65. MT default 0.9 (slower due to crane sequencing between erection and decking). Blend: super = (floor × 0.6) + (vol × 0.4).

Vol/floor blend (vol weight)

%(all systems — floor weight = 100% minus this)

How much weight the volume-throughput component gets in the superstructure blend. Floor cycle gets the remainder. 40% vol / 60% floor = default.

Envelope / Enclosure

–

Gantt phase total — live

Envelope rate (m²/wk)

m²

Facade m² installed per week. Envelope dur = facade_m² / rate. Facade = perimeter × storeys × floor height. Min 4 wks regardless of size.

Envelope starts after floor #

Cladding starts once this many floors are erected. MT: prefab panels arrive bay-ready, direct screw-fix (4 fl). CIP: reshoring + slab cure + bracket install lag (5 fl typical, ≈28-day cure + reshore strip + survey/bracket). Steel: deck pour and cure for anchor points, 2–4 fl behind erection (4 fl). Adjust based on cladding system and formwork method.

MEP Rough-in

–

Gantt phase total — live

MEP start (% of super)

same

MEP rough-in begins when this % of superstructure is complete. MEP also constrained to finish ≥2 wks after envelope ends.

Suites roughed-in per week

sts

same

MEP suites (or equiv. units) completed per week per active floor. Suite sizes: residential 75 m², office 200 m², industrial 500 m², boutique 150 m².

MEP active floors (concurrent)

Number of floors with active MEP crews simultaneously. MT default 3: no formwork or wet-concrete curing means MEP trades can access the floor above while superstructure continues below — a real parallel-access advantage. CO/ST default 2: slab strip & cure limits access. Separate from the 0.90 MT duration factor (prefab wiring harnesses, cleaner ceiling grid — two distinct mechanisms).

MEP riser weeks per floor

wks/fl(all systems)

Riser/trunk routing weeks = storeys × this rate. Combined with suite weeks per the overlap setting below.

MEP riser overlap

%(all systems)

How much riser routing runs concurrently with suite rough-in. 100% = fully parallel (old behaviour, riser hidden unless it exceeds suite weeks). 0% = fully sequential (riser weeks add on top). MEP weeks = longer of the two + (1 - overlap) × shorter.

MEP duration factor

Suite MEP duration multiplier per system. CIP (concrete) is the reference at 1.00; raise it to model a longer concrete rough-in, lower MT/ST for prefab wiring or cleaner ceiling advantages. Applied to the suite portion only, not riser weeks.

Interiors / Finishes

–

Gantt phase total — live

Interiors start (% env done)

Interiors begin once this % of envelope is complete. Set per system. Also constrained to finish ≥2 wks after MEP.

Finishing crews per floor

crews(all systems)

Painting, flooring, fixtures crews working simultaneously on one floor. More crews = faster per-floor completion.

Suites per crew per week

sts(all systems)

Interior finishing rate per crew per week. Finish wks/floor = suites_per_floor / (crews × this rate).

Active finishing floors

fl(all systems)

Floors finishing simultaneously. Total interiors dur = (finish_wks/floor × storeys) / active_floors.

All values above feed directly into the schedule engine — no hidden multipliers. Superstructure = (floor_cycle × storeys × floor_weight) + (vol/crew × vol_weight). Foundation weeks = max(min_wks, base_wks × load_ratio). Envelope = facade_m² / rate. MEP = max(riser_wks, suites / (suites_per_wk × active_floors)). Interiors = (suites_per_floor / (crews × rate) × storeys) / active_floors.

Schedule savings use site GC% and financing rates from the Estimator tab. All phase durations computed from the Schedule Dynamics inputs above — change any value and both the Gantt and Estimator update immediately.

Core / Lateral Schedule Impact

Table 17MT Core System — Schedule & Cost Parameters

Core schedule impact is modelled as a separate Gantt phase. Core wks/floor and lead floors determine when superstructure can start and whether the core constrains floor erection pace. Parallel cores (CLT, CBF) run alongside gravity framing. Leading cores (CIP, precast) must build ahead before floor erection begins.

Core System	Wks/Floor	Lead (floors)	Parallel?	Cost Premium %	Notes

Schedule savings use site GC% and financing rates from the Estimator tab. Foundations duration driven by structural weight (MT ~500 kg/m³, Steel ~7,850 kg/m³, Concrete ~2,400 kg/m³) + typology live/dead loading. Superstructure = weeks/floor × storeys + volume / crew output (MT 120 m³/wk, Concrete 180 m³/wk, Steel 35,000 kg/wk). Envelope starts N floors behind the active pour/erection: MT 4 fl (prefab panels, direct screw-fix), CIP 5 fl (reshoring + 28-day cure + bracket install), Steel 4 fl (deck pour + cure). MEP starts at 50% of superstructure for all. MT Interiors duration uses the same fit-out rate as CO/ST — driven by suite count, crew size, and active floors per the schedule parameters above.

Mass Timber Crane Analysis ✎ All inputs editable — updates live

Crane Hours

Hours per day 8.0 hr/day Days per week 5 days/wk

CLT Panel Size

Thickness (mm) Width (m) 3.0 m Length (m) 12.0 m

Vol: — m³ · — kg

Glulam Member Size

Width (mm) 175 mm Depth (mm) 456 mm Length (m) 7.0 m

Vol: 0.558 m³ · 279 kg

Pick Cycle Time

Beam / column (min/pick) 12 min Panel (min/pick) 12 min

Hook Speed / Height

Hoist speed full load (m/min) 60 m/min Floor-to-floor height (m) 3.2 m

Tower Crane Reach

Jib reach (m) 50 m Tip capacity at reach (t) 3.0 t

—

Spider Crane & Bundling

Spider crane for column placement Spider reach (m) 8 m

—

Enable for bundling + parallel placement.

Crane Sharing

% time for envelope / facade 15% Rigging / dunnage overhead 15%

Member Count Overrides — leave blank to use calculated values from volume ÷ avg member size

Total glulam beams & columns

Calculated: —

Total CLT floor panels

Calculated: —

Total CLT core wall panels

Calculated: — (panels capped at 12 m length)

Crane analysis loads when Schedule tab is active. Inputs driven from Estimator tab (MT intensity, floor area, storeys, glulam/CLT ratio).

	MT	CIP	ST
Cycle time	—	—	—
Project turns / horizon	—	—	—
Equity multiple / cycle	—	—	—
Compounded equity (horizon)	—	—	—

Structural System Cost Estimator

SensitivityTornado Chart — MT Net All-In vs CIP Concrete ($/m²)

LiveAssumptions & Provenance

Table 1Material Intensity by Building Typology (m³/m²)

Table 1aMeasured US Mass-Timber Buildings — Timber, Concrete & Steel Intensity (validation)

Table 2Material Intensity by Structural System Type (m³/m²)

Table 3MT Package Pricing Basis ($/m³) — edit frequencies to recalculate weighted average — Canadian reference (CAD project records); US mode prices CLT and glulam from the US unit rates below

Table 4Fire Rating Impact on Material Intensity — Glulam vs. CLT Split

Table 5NBC 2020 Encapsulation Requirements by Building Type — Canadian reference; US mode prices IBC 2021 Type IV protection (§602.4)

Table 5eMass Timber Insurance — Course of Construction & Operational Benchmarks

Table 6Concrete Structural Systems — Intensity, Types & Cost Drivers (m³/m²)

Table 6a12–18 Storey CIP Concrete — Structural Intensity by Market & System (m³/m²) — measured US and Canadian rows in A2 and D are small cohorts: read them as bands

Table 6bPodium Structural Grid — Concrete Intensity & Cost Basis

Table 6cCIP Concrete Intensity by Seismic Category, Wind & Building Size — measured, designed and the estimator (m³/m²)

Table 7Concrete Frame Rate by Market — the slider seed, from the concrete rate model ($/m³)

Table 7cConcrete Rate Model — first-principles $/m³ by element (DATA.concreteRateModel, model/concrete-rates.mjs)

Table 7bPost-Tensioned Floors — the one PT model (DATA.ptParams, model/pt-floor.mjs)

Table 8Foundation Calculation Parameters — DATA.foundationParams

Table 9Transfer Slab Types — Cost & Schedule by Configuration

Table 10Gypsum / Finish Allowance for Like-for-Like Scope ($/m²)

Table 10aLCA Embodied Carbon Benchmarks — Concrete Structure (kg CO&sub2;e/m² GFA) — measured US and Canadian rows are small cohorts: read them as bands

Table 11Steel Intensity — Used by the Estimator, with Published Benchmarks (kg/m²)

Table 12Steel Rate by Market — Supply + Fab, Erection, Installed ($/kg)

Table 13Add-ons for Like-for-Like Comparison, and the Fire Rating the Frame Needs ($/m² of floor)

Table 14This Building’s Steel Structure — Cost Build-up from the Estimator

Table 15Oil Price Impact on Structural Cost ($/m² delta from $60/bbl baseline)

Table 16Carbon Price Impact on Structural Cost ($/m² delta from $0/tonne baseline)

Table 20Full Construction Cost Stack Benchmarks — Canadian Mid-Rise Residential ($/m² GFA)

Table 21MT Acoustic Topping Types — Load & Cost Reference

Table 22Market Cost Index — MEP, Finishes & Envelope (absolute multiplier on base; loads the slider per city)

Table 23Parkade, Encapsulation & Conveying Parameters — DATA reference

Table 24Schedule Base Superstructure Weeks by Typology — DATA.scheduleWeeks

Table 26Core / Lateral System Intensity by City

Table 27MT Core System — Schedule & Cost Impacts ✎ Editable — all calculations update on change

Table 28Seismic Reference Weights — DATA.seismicWeights & Core Scaling

LiveLife Cycle Assessment — Embodied Carbon Comparison

SensitivityTornado Chart — moved to the Configuration tab

Assumptions AuditAdjustments from Default — Conservatism Tracker

LiveCalculations Audit

Table 25Schedule Dynamics — All Variables Exposed

Table 17MT Core System — Schedule & Cost Parameters

⚙ Data Source Check

⚙ Compute Snapshot & Compare

Competitive Matrix: MT vs CIP Concrete

Table 3MT Package Pricing Basis ($/m³) — edit frequencies to recalculate weighted average

Table 5NBC 2020 Encapsulation Requirements by Building Type

Table 6a12–18 Storey CIP Concrete — Structural Intensity by Market & System (m³/m²)

Table 10aLCA Embodied Carbon Benchmarks — Concrete Structure (kg CO&sub2;e/m² GFA)