Engineered Outperforms Open Web

In residential construction, a truss is a prefabricated framework for roofs or floors. They are often made from wood and used to support loads by transferring weight through interconnected triangular units.

In single-family and multifamily projects, floor trusses are designed to span between walls or beams to carry the weight of people, furniture, and appliances across each level of the building. Roof trusses are engineered to support roofing materials and handle loads like snow, wind, and the roof’s own weight. Each type is built to meet its specific structural role and cannot be placed elsewhere.

Floor trusses are made from two horizontal members (called chords) with a triangular or webbed pattern of diagonal and vertical members connecting them. These components are usually made from dimensional lumber.

Sometimes called plated floor trusses, open web trusses are built using dimensional lumber connected with metal connector plates. In single-family and multifamily projects, plated floor trusses are often used. However, they typically require longer lead times, more on-site labor, and specialized handling compared to engineered I-joists.

BCI Joists weigh about one-third less than floor trusses. Their lighter weight allows for installation without a crane and fewer people. There also isn’t a top or bottom orientation for I-joists, which simplifies placement. Floor trusses have specified top and bottom chords for installation. (BCI joists are light but mighty)

Yes. BCI Joists are field trimmable, making on-site adjustments easier. Floor trusses typically are not designed to be trimmed in the field. If modifications are needed, often a new open web joist must be made, potentially slowing construction and adding to the overall cost.

BCI Joists have published floor assemblies that meet the 2015 IRC 302.13 fire protection standards. Floor trusses are also required to meet IRC 302.13, but there are no exceptions for trusses or I-joists—only for dimensional lumber 2×10 or larger. Draft stopping may also be required every 1,000 sq. ft. when using trusses.

Floor trusses often need bracing or strongbacks at mid-span, adding 2–3% to the cost. BCI Joists generally do not need additional support under standard loading.

BCI Joists can use a full-depth rim board at the end bearing, eliminating the need for extra blocking. Ribbon boards used with floor trusses do not provide a direct lateral load transfer path; trusses often needblocking or a rim board, depending on local code and wall bracing needs. This is especially needed in higher lateral load areas.

Floor trusses are often deeper than BCI Joists. BCI Joists often achieve similar spans with shallower depths, allowing more design flexibility, especially in elevation-sensitive projects. It’s important to remember that BCI joists are available in depths from 9 ½” to 24”, creating a wide variety of options to meet a project’s structural, spans, and design criteria.

Floor truss costs can fluctuate with lumber markets and are priced per job. BCI Joist pricing tends to be more stable because of controlled manufacturing processes and a stable supply chain of raw materials for engineered wood products. Costs vary by project, but often open web floor trusses cost more. Their prices can fluctuate with lumber market volatility and can make pricing jobs more challenging. BCI Joists, however, offer a predictable price since engineered wood products rely on controlled manufacturing processes and stable supply chain of consistent raw-material inputs — not the fluctuating commodity lumber market.

Yes. BCI Joists can allow field modifications and quick repairs, helping projects stay on schedule. If trusses are not installed correctly or missized, new trusses will need to be made, which leads to delays.

BCI Joists are dimensionally stable, offering predictable performance and are precision-manufactured with specific moisture content, all of which helps eliminate movement and potential floor squeaks. All Boise Cascade products also come with a limited lifetime warranty.

BCI Joists support multiple large openings and access points, allowing flexibility in duct layout and mechanical room placement. Floor trusses have multiple access points for routing mechanicals and their opening sizes change based on span and configuration. Floor trusses are often made with larger chases in the center to run large HVAC options, which limits layout options and may mean longer HVAC runs.

Yes, for Trusses. The open plenum can allow sound to travel between joists. BCI Joists reduce this issue as their webbing helps act as a sound barrier.

Trusses use metal gusset plates, which can nick wires. BCI Joists do not use metal plates and come with pre-manufactured 1 ½″ knockouts for wiring and small plumbing runs. For larger plumbing and mechanicals, holes up to 22” can be easily cut into BCI joists.

Trusses typically require engineer-sealed calculations, shop drawings, and full instructions for permits, per IBS 2303.4. BCI Joists do not. Their capacities are established under IRC Section R502.1.2 and ASTM D5055, and are validated through ICC-ES Evaluation Report ESR-1336—eliminating the need for additional engineer seals or calculations in most cases.

Floor trusses have to be designed and assembled for each job, which leads to longer lead times for jobsite delivery. BCI Joists are part of a stable supply chain, held in local inventory, providing quick and predictable delivery schedules often in as little as 24-48 hours.

BCI Joists come with a limited lifetime warranty when installed per Boise Cascade guidelines. Trusses typically do not include a warranty for the builder or property owner.