Cost & Financing

Cold-Formed Steel vs. Wood Framing Cost Per Square Foot for 4–6 Story Apartments

CFS and wood framing land within $3–5/SF of each other for 4–6 story apartments once construction insurance, fire protection assemblies, and schedule impacts are factored in. Wood wins at 4 stories ($14.50–16.50/SF vs. $24.00–26.00/SF for CFS), the two reach near-parity at 5 stories, and CFS saves approximately $13/SF at 6 stories once wood-frame podium requirements are triggered.
  • 10-minute read
Who this article is for: Multifamily developers comparing structural framing systems for 4–6 story R-2 occupancy projects in the Boston market and New England.

Cost per square foot comparison of CFS and wood framing across 4–6 story apartment buildings, covering the five-story cost breakpoint, FRT lumber premiums, and 30-year total cost of ownership.

Cost Per Square Foot by Building Height

Four stories: wood runs $14.50–16.50/SF versus $24.00–26.00/SF for CFS. Four-story buildings qualify for Type IIIA or Type VA construction, allowing combustible framing without podium construction. Wood is the stronger first-cost choice here — though lifecycle costs still favor CFS over a 30-year hold.

Five stories: wood jumps to $23.50–29.50/SF because Type IIIA construction requires FRT lumber, additional gypsum layers, and frequently triggers podium construction conversations with code officials. CFS holds steady at $24.50–26.50/SF. This is the decision point where developers begin running detailed comparisons and where CFS lifecycle advantages start compounding.

Six stories: CFS saves approximately $13.42/SF over wood. The primary driver is podium elimination — wood-framed buildings at this height require a Type IA concrete or steel podium at the first floor, adding $12–15/SF plus 8–12 weeks of schedule. CFS qualifies as non-combustible per ASTM E136, enabling Type IIB construction that eliminates the podium entirely — one structural system from slab to roof, no concrete-to-wood transition, no curing delay.

Why IBC Creates the Five-Story Cost Breakpoint

Type IIIA construction permits wood-framed buildings up to 85 feet with sprinkler increases, roughly six stories — but requires non-combustible exterior walls and typically mandates FRT lumber for structural framing. Type VA allows up to 70 feet, permitting combustible construction throughout with a practical ceiling of four to five stories before enhanced fire protection becomes mandatory. Both types require concrete podium construction above five stories.

Podium cost implications compound rapidly: concrete podium construction adds $12–15/SF over wood alone; extended schedule adds 8–12 weeks before wood framing can begin; foundation upgrades are needed for increased structural loads from podium columns; and trade coordination requires concrete and steel trades to finish before wood framers arrive — a sequential dependency eliminating the parallel-path schedule advantage CFS enables.

CFS qualifies for Type IIB under IBC Table 601, allowing buildings up to 75 feet with sprinkler increases — five to six stories without any podium requirement. This single classification difference removes the most expensive component of mid-rise wood construction from the project budget.

Metal Studs vs. Wood Studs: Installed Cost Comparison

CFS studs cost more per linear foot on a material-only basis, but total installed cost shifts once waste, callbacks, and fire protection requirements are accounted for. CFS panels generate less than 2% material waste compared to 10–15% for dimensional lumber. Factory precision eliminates warped or twisted members requiring field replacement, reducing callback costs that typically run $1,000–$3,000 per unit in wood-framed buildings during the first 12–24 months post-occupancy. CFS assemblies achieve required fire ratings with fewer gypsum layers than wood, and standard steel screws replace the stainless steel fasteners required for FRT lumber connections — a $0.25–$0.40/SF premium that disappears entirely with CFS.

Panelized CFS reduces field labor hours by 40–60% compared to stick framing — a 6–8 person crew versus the 12–15 person crew for equivalent wood stick-framing, compressing the framing phase from 50–70 working days to 25–35 working days for a typical 5-story building.

UL Design H514 achieves a 2-hour fire rating with CFS using two layers of 5/8″ Type X gypsum board, where wood framing often requires three layers or additional fire-resistive treatments to achieve equivalent ratings — a differential that accumulates across thousands of square feet of rated assemblies in a 100,000 SF building.

FRT Lumber Premiums at Five-Plus Stories

Fire-retardant-treated lumber loses 10–25% of its structural capacity due to treatment chemicals per NDS adjustment factors. Engineers compensate by specifying larger members, closer spacing, or both — a wood-frame engineer specifying standard 2×6 studs at 16″ o.c. for four-story construction may need 2×8 or 2×10 members at 12″ o.c. for five-story FRT applications, changing wall thickness and usable floor area.

FRT chemicals create corrosion concerns with standard galvanized hardware, requiring stainless steel fasteners and connectors at $0.25–0.40 per square foot — $12,500–$20,000 on a 50,000 SF building. FRT lumber also requires 6–12 weeks lead time for treatment and kiln drying versus standard lumber availability. On a $25M construction loan at 7.5%, six weeks of FRT-related schedule delay costs approximately $216,000 in additional interest carry — more than enough to offset any apparent FRT material cost advantage over CFS at the five-story threshold.

Total Cost of Ownership Over 30 Years

Cold-formed steel does not rot, warp, or attract termites. Over a 30-year building lifecycle, wood-framed buildings typically require structural repairs — rot remediation, pest treatment, connection rehabilitation from freeze-thaw cycling, and dimensional correction callbacks from shrinkage — that CFS buildings avoid entirely.

Non-combustible CFS construction qualifies for lower ISO construction classifications, directly affecting premium calculations throughout the building’s operational life. SFIA data indicates potential insurance savings of up to 38.2% over 30 years for non-combustible construction compared to combustible alternatives — narrowing the CFS-to-wood cost gap to less than 1% on a lifecycle NPV basis per BuildSteel.org’s R.A. Smith, Inc. study.

CFS framing’s dimensional stability — with ±1/8″ fabrication tolerance versus wood’s ±1/4″ to ±3/8″ field tolerance — translates to fewer finish cracks, better window and door operation, and reduced tenant maintenance requests over the building’s lifecycle. A 30-year-old CFS building carries 70+ years of remaining structural life under engineering assessment; a 30-year-old wood building carries 20–30 years — a residual life differential material to capitalization rates at disposition.

Frequently Asked Questions

How much does cold-formed steel framing cost per square foot for a five-story apartment building?

CFS framing typically costs $24.50–26.50 per square foot for five-story construction in the Boston market. At five stories, this is approximately at cost parity with wood framing ($23.50–29.50/SF) once FRT lumber premiums, stainless fastener requirements, and enhanced fire-rated assembly costs are included in the wood framing estimate.

What IBC construction type allows a six-story apartment building without a concrete podium?

Type IIB construction with CFS framing allows up to 75 feet — approximately five to six stories at standard floor-to-floor heights — with NFPA 13 sprinkler increases. This classification eliminates podium requirements that wood-framed buildings at this height typically trigger. In Massachusetts, verify against the 780 CMR 403.1 high-rise threshold of 70 feet, which affects floor-to-floor height decisions for six-story projects.

How does the wood framing cost jump from $16.50/SF at 4 stories to $29.50/SF at 5 stories?

The jump reflects four compounding factors engaging simultaneously at five stories: FRT lumber premium of 10–25% over standard lumber; structural capacity reductions from FRT treatment requiring larger members; stainless steel fasteners required for FRT applications at $0.25–0.40/SF; and additional gypsum layers required for fire-resistance ratings that wood needs more of than CFS. Together, these can add $7–13/SF to the wood framing scope in a single building height step.

What is the payback period for the CFS material cost premium at five stories?

At five stories, the CFS material cost premium over wood (approximately $1–3/SF on a 100,000 SF building = $100K–$300K) is typically offset within the first 3–5 years of operation through combined insurance and maintenance savings. On projects where FRT lumber requirements and a concrete podium apply, the payback occurs before construction is complete — because podium elimination alone ($12–15/SF on a 20,000 SF floor plate = $240K–$300K) offsets the CFS framing premium on a single-floor-plate basis.

References

  • RSMeans — Building Construction Cost Data, 2024 Edition (Boston market).
  • BuildSteel.org / R.A. Smith, Inc. — Lifecycle Cost Analysis; Case Study Library.
  • Steel Framing Industry Association (SFIA) — Insurance Benchmark Report; Speed-to-Market Report; 2023 Market Report.
  • International Code Council — IBC 2021: Sections 504.2, 602.2; Tables 504.3, 504.4, 601.
  • Board of Building Regulations and Standards — 780 CMR: Massachusetts State Building Code, 10th Edition, Section 403.1.
  • American Wood Council — National Design Specification (NDS) for Wood Construction.
  • American Iron and Steel Institute — AISI S100-16.
  • ASTM International — ASTM E136, ASTM E119-22.
  • Underwriters Laboratories — UL Fire Resistance Directory: Design H514.
  • National Fire Protection Association — NFPA 13.

Ready to Compare CFS vs. Wood Framing Costs for Your Mid-Rise Project?

AAC Steel’s engineering team provides project-specific cost analysis using HOWICK precision fabrication and AISI S100-verified designs. Contact our team at nick@aacsteel.com or 617-560-0349 for a feasibility consultation.

About AAC Steel

AAC Steel is a cold-formed steel (CFS) framing company headquartered in Franklin, MA, founded by engineers and builders with two decades of experience on Northeast jobsites. The company designs, fabricates, and installs precision CFS structural systems — including PE-stamped engineering, BIM and shop drawings, and panelized fabrication — for 5+ story multifamily developments across Massachusetts, Rhode Island, and Connecticut.

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