Engineered Wood for
Multi-Family Construction
Build apartments, condos, and mixed-use faster and more affordably — with fire-rated, acoustically rated, dimensionally stable wood framing engineered for mid-rise density.
From podium “5-over-1” apartments to workforce and student housing, RedBuilt’s Red-I™ joists, RedLam™ LVL, open-web trusses, glulam, and offsite systems deliver the spans, ratings, and schedule multi-family demands.
Why Engineered Wood for
Multi-Family?
Mid-rise wood framing is the dominant model for U.S. apartments because it hits the developer’s two targets at once — more rentable units per acre and lower cost per square foot. Wood framing runs roughly 60–70% less per square foot than concrete or steel for residential floor plates, and it builds faster once the podium is complete.
RedBuilt makes that model perform by engineering the floor, roof, and load-path components to the project’s exact spans, loads, and ratings.
Multi-Family Benefits
Fire-rated assemblies
Engineered wood floor/ceiling systems achieve the required fire-resistance ratings through tested assemblies — often 1-hour between units.
Quiet floors (acoustics)
Assemblies are designed to meet or exceed STC ≥ 50 and IIC ≥ 50, controlling airborne and impact sound between units.
Dimensional stability
Low-moisture engineered products resist the shrinkage, crowning, and squeaks that plague many-unit lumber floor.
Long, open spans
Longer clear spans reduce bearing walls and columns, opening unit layouts and parking below.
In-floor MEP routing
I-joist and open-web geometry lets HVAC, plumbing, and electrical run within the floor depth — critical for tight mid-rise floor-to-floor heights.
Speed & lightweight
Less weight, built-to-order members install fast with fewer workers, shortening schedules.
Construction Types & Code
Multi-family wood construction is governed by building type and sprinkler strategy. RedBuilt’s team helps design teams navigate the path:
Podium / “5-over-1.”
Five wood-framed stories over a concrete podium (retail, amenities, or parking), separated by a 3-hour fire-rated horizontal assembly.
Type III & Type V
The upper wood floors are typically IBC Type III or V; RedBuilt engineers the framing to the required ratings.
Sprinklers (NFPA 13R vs. 13)
The 2021 IBC measures the four-story wood limit and height cap from grade plane; a full NFPA 13 system unlocks additional height and area.
Products for Multi-Family
A complete engineered-wood system for apartments, condos, and mixed-use — coordinated to work together:
Fire & Acoustic Performance
Between-unit floors must satisfy both fire and sound codes. Engineered wood assemblies are designed to deliver:
Fire resistance
Tested floor/ceiling assemblies achieve the required rating (commonly 1-hour between dwelling units).
Sound control
Assemblies meet or exceed STC ≥ 50 (airborne) and IIC ≥ 50 (impact), tested per ASTM E90 and E492.
Smart product selection
As on The 951, choosing the right joist series, depth, and spacing can meet the fire rating while reducing gypsum layers — saving cost and floor depth.
Controlling Shrinkage & Movement
In four- and five-story wood buildings, cross-grain shrinkage at plates, joists, and rim boards can accumulate meaningfully per floor — cracking drywall and stressing finishes and MEP if not managed. RedBuilt’s engineered products come off the press at low moisture content, so they barely move: RedLam™ LVL rim and Red-I™ joists hold their dimensions where solid lumber shrinks and crowns, keeping many-unit buildings flat, aligned, and quiet.
Offsite & Speed-to-Market
With skilled labor scarce and financing costs high, time is money. RedBuilt’s built-to-order manufacturing and offsite/panelized options deliver components ready for fast installation — reducing on-site labor, waste, and errors. Building-science data attributes up to ~50% faster construction and ~20% cost savings to prefabrication.
Wood is the renewable structural choice: it stores carbon for the life of the building and carries lower embodied carbon than concrete or steel — documentable via EPDs and supported by FSC/SFI-certified sourcing.
For developers pursuing LEED® or green financing on multi-family, that’s a measurable advantage.
Proven in the Field
The 951 (Boise, ID)
A four-story, 74,500-sf mixed-use building with 68 apartments over ground-floor retail — roughly 70,000 sf of it framed with RedBuilt products.
The RedBuilt team collaborated with the contractor and engineer to solve the building’s hardest problems: high-strength 2.0E RedLam™ LVL with embedded hold-down anchors carried the wind and seismic lateral loads that intensify at four-plus stories; low-moisture Red-I™ joists, RedLam™ rim board, and beams cut expected wood shrinkage; and a redesign to a higher joist series at 24″ on-center achieved the required fire rating while eliminating a second layer of gypsum board.
Resources and Downloads
Everything a design team needs to spec RedBuilt for multi-family.
Nationwide Manufacturing + Support
RedBuilt manufactures and supports multi-family projects nationwide from four U.S. plants, with design centers and in-market technical reps embedded in local markets:
- Manufacturing plants: Chino, CA; Delaware, OH; Hillsboro, OR; Stayton, OR.
- Design centers: Boise, ID; Chino, CA; Delaware, OH; Hillsboro, OR.