Steel Joists & Joist Girders

Steel Joists & Joist Girders

Steel joists and joist girders are key components of today’s roofing and flooring systems. Whether you are designing a single or multistory structure, steel joists and joist girders are an efficient, cost-effective solution that can add a great deal of value to your structure.

In accordance with the standards set by the Steel Joist Institute (SJI), Vulcraft manufactures a full range of joists, including standard joists, joist girders, and composite joists, designed to work compositely with the concrete slab that is placed on top of the steel deck, creating a very efficient floor system.

In addition, Vulcraft can design and manufacture specialty joists, such as gable joists and barrel joists, to help the architect and engineer bring a specific vision to life. These joists can be a strong architectural asset to the structure just as much as they are a significant structural element to the building.

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K-Series joists are designed for use typically with lighter loads and are most common in roof design. K-Series Joists are used typically where shorter span conditions are required.


KCS-Series Joists are a version of the K-series joists, but designed for a constant shear and moment, which allows for greater flexibility for locating extra loads such as those from rooftop units.


LH-Series Joists are for longer span conditions and are capable of supporting larger loads. These joists allow for special profiles to accommodate a variety of conditions. Some of the typical special profiles include gable joists and arched joists.


As with LH-Series joists, DLH-Series (Deep Longspan) joists are for longer span conditions and support larger loads. With standardized depths from 52” through 120” and spans up through 240 feet, DLH joists also allow for special profiles to accommodate a variety of conditions.

Composite Joists

The Composite Joist, or CJ-Series, system is an open web system where the concrete slab acts as the composite top chord of the underlying steel joists. Shear transfer from the concrete slab to the underlying steel joists is accomplished by welding steel shear studs through the steel deck to the steel joist top chord. Each joist is designed with a sufficient number of steel shear studs to develop the yield strength of the bottom chord. The CJ-Series exhibits a stiffer response to applied loads as compared to conventional steel joist systems.

Another option using composite joists is our Ecospan® Structural Floor System, which, instead of a welded shear stud, uses a Shearflex® Fastener. The self-tapping, self-drilling heat-treated Shearflex fastener not only attaches the deck to the joists but also acts as the shear connector between the steel and the concrete. Click here for more on the Ecospan Structural Floor System.

Specialty Joists

Joist Options

Joist Girders

Joist girders are primary framing members. The design is simple span, supporting equally spaced concentrated loads from open web steel joists. Joist girders are designed to allow for the efficient use of steel in longer spans for primary framing members.