Floor Truss

Back to Glossary

Floor Truss

What is Floor Truss?

Engineered structural components made from lumber and metal connector plates that span between supports to carry floor loads efficiently.

Description

Floor trusses are engineered structural components consisting of lumber members connected with metal connector plates to form triangulated frameworks that span between supporting elements to carry floor loads and transfer them to the building’s structural system. These prefabricated assemblies offer significant advantages over traditional solid lumber joists, including longer spans, reduced material usage, lighter weight, and integrated spaces for utilities and mechanical systems. Floor trusses are designed using engineering principles that optimize material efficiency while providing superior structural performance, making them increasingly popular in residential and commercial construction where clear spans, utility integration, and cost-effectiveness are important considerations.

The primary purposes of floor trusses include supporting floor loads over longer spans than conventional joists, providing integrated pathways for utilities, plumbing, and HVAC systems, reducing material usage through efficient engineering design, enabling faster installation compared to stick-built floor systems, creating clear spans that eliminate the need for interior bearing walls, offering consistent quality through factory manufacturing and quality control, and providing design flexibility for architects and builders in space planning and structural layout.

Construction of floor trusses involves precision manufacturing using kiln-dried lumber for chords and webs, galvanized steel connector plates that join lumber members at connection points, engineered design that optimizes member sizes and configurations for specific load and span requirements, quality control processes that ensure consistent manufacturing standards, and delivery systems that coordinate truss installation with construction schedules.

FAQs

  • What is a floor truss?

    A floor truss is an engineered structural component made from lumber and metal connector plates that spans between supports to carry floor loads more efficiently than traditional joists.

  • What are the advantages of floor trusses?

    Advantages include longer spans, integrated utility pathways, lighter weight, consistent quality, reduced material waste, and greater design flexibility.

  • How far can floor trusses span?

    Floor trusses can commonly span 20 to 40 feet or more in residential applications, significantly exceeding the capabilities of conventional joists.

  • How are floor trusses installed?

    Installation requires proper handling, crane equipment for larger trusses, correct bearing and connections, temporary bracing during installation, and permanent bracing as specified.

  • Can utilities run through floor trusses?

    Yes, the open web design provides natural pathways for ductwork, plumbing, and electrical systems without compromising structural integrity.

  • Are floor trusses more expensive than regular joists?

    Initial costs are typically higher, but savings from reduced labor, material waste, and utility installation often offset the additional cost.

  • Do floor trusses require special design?

    Yes, floor trusses must be engineered for specific loads and spans by qualified professionals and manufactured by certified facilities.

Fun Fact

Fun Fact: The first engineered wood trusses were developed in the 1950s, but floor trusses didn’t become widely used until the 1980s when improved connector plate technology and computer-aided design made them more practical and cost-effective for residential construction.

CSI Code

06 17 00

NAHB Code

615