Why Open Web Floor Trusses Are the Best Choice for Your Next Build

When designing a floor system, one of the most important decisions is selecting the right framing method. The joist system must be strong enough to support the floor above and the ceiling below while also allowing for the necessary utilities, such as plumbing, HVAC, and electrical.

Traditional floor framing methods, like solid sawn lumber joists and I-Joists, have been the industry standard for decades. However, these methods come with challenges, such as limited span capabilities, extra labor for modifications, and material inefficiencies that drive up costs and waste.

If you're looking for a stronger, more efficient, and cost-effective alternative, open web floor trusses offer a superior solution. These pre-engineered trusses provide longer spans, better utility access, and faster installation, making them the ideal choice for residential, multi-family, and commercial projects. In this post, we’ll explore how open web floor trusses work, how they compare to traditional framing methods, and why they’re the best choice for your next building.

Traditional Floor Framing

Before we explore the benefits of open web wood floor trusses, let’s look at the conventional floor framing methods, solid sawn lumber joists and I-Joists.

Solid Sawn Lumber Joists

This method of floor framing uses a single 2x8, 2x10 or 2x12 piece of lumber which spans from one support to the other. The distance that the floor can span is limited to how strong that single piece of lumber is, which is inefficient compared to other methods.

Solid Sawn Lumber Joists require drilling for any HVAC, plumbing or electrical systems you might want to conceal in the floor, weakening the joists, increasing labor time and cost and could require additional reinforcements.

I-Joists

This method of floor framing uses solid wood for the top and bottom with OSB or plywood in between which transfer the forces from the top to the bottom and out to the ends of the joist. I-Joists can span longer distances and are more material-efficient than solid sawn lumber but still requires drilling for utilities and are expensive when built for longer spans.

The Core Problem

While these methods of floor framing are the most common, they require modifications to fit ductwork, plumbing and electrical, driving up the cost of material, labor and time. They also result in more waste going to the landfills, increasing the environmental impact of home building.

Holes drilled into an I-Joist with wiring going through

Open Web Floor Trusses are your Solution

Open web floor trusses are pre-engineered, labor saving and cost effective. They are best utilized in multiple story buildings, whether that be multi-story residential, residential with a basement, commercial or multi-family.

Due to the need for a crawl space, the first level of the home is often built with a shallow I-Joist and multiple supports. For every other floor, open web floor trusses allow for larger open spaces and can span up to 36 feet. This large span reduces the need for any interior support beams or columns.  

Open web floor trusses consist of a top chord supporting the floor above and a bottom chord supporting the ceiling below. The chords are made with 2x4s, which in this instance are referred to as 4x2s because they are laid flat on the thicker side, allowing for a wide nailing surface.

In between these chords are webs, commonly in a Warren or Pratt pattern. The webs are joined to the chords by metal plates, like a roof truss. Just like a roof truss, the load is distributed through the truss, from the top, through the webs to the bottom chord, into the bearings.

These trusses use less wood while maintaining strength. An 18” tall truss uses the same amount of material as a 2x10, but can be spaced farther apart. Truss depth and spacing can be customized for any load requirement such as hot tubs, pool tables or large furniture.

Due to the web pattern of this truss, there is no need for drilling holes. Builders can fit any HVAC, plumbing or electrical through the openings in the webs. Installing these in a conditioned space is better for the environment and reduces your power bill. It also reduces the need to install the ductwork below the floor system, which could cause the need for soffits and make a flat ceiling impossible.

If you are using I-Joists or solid sawn lumber joists, they come out to the job site roughly cut. The framer on site has to cut them to the exact length they need. If you are using pre-manufactured floor truss, like the open web floor truss, they are built at the exact length they need to be. Trusses can be delivered to the job site and set in place immediately.

Floor trusses reduce the need for hangers when placed on a bearing. The top chord extends over the bearing, concealing the beam and keeping the ceiling flat. Additionally, a rim joist isn’t required—trusses can be notched to fit a 2x4, which ties them together for added stability.

Your truss supplier will do everything they can to make sure that the trusses come out to the job site correctly, with no need for modification. If there is a need for a modification, we will reach out to the engineer who designed the trusses and find out what the appropriate modification is. In the worst-case scenario, we can just replace a truss. Not a big deal.

Open web floor trusses are designed to let ductwork, plumbing, and electrical pass through the webs effortlessly, keeping everything inside the conditioned space.

The top chord of this open web floor truss extends over the beam, concealing it and keeping the ceiling flat.

Conclusion

Choosing open web floor trusses isn’t just about structural performance—it’s a smart financial decision. By reducing the need for interior support beams, eliminating the extra labor required for utility modifications, and optimizing material usage, these trusses lower both material and labor costs.

Unlike solid sawn lumber joists or I-Joists, which require additional on-site cutting and drilling, open web floor trusses arrive pre-cut and ready to install. This significantly reduces construction time and minimizes waste, cutting down on expenses for materials, labor, and disposal fees.

Additionally, their energy-efficient design helps lower long-term costs by keeping ductwork within the conditioned space, reducing heating and cooling expenses.

 From initial installation to long-term energy savings, open web floor trusses offer a faster, more cost-effective, and environmentally friendly solution for floor framing. If you're looking for a better way to build, open web floor trusses are the answer.