Last week I was downloading some photos from my digital camera, and I stumbled across hundreds of forgotten photos I shot while my daughter’s new home was being built on Mount Desert Island, off the coast of Maine.

I was there every day for the first few months and I did my best to capture each part of the process. One of my favorite aspects of the construction of the home was the use of floor trusses instead of floor joists.

I suggested that floor trusses be used for a few reasons, not the least of which is that they produce amazingly flat floors with no bounce. My daughter wanted tile floors throughout the home because of a dust allergy, and flat floors with no bounce are a must for large-format tiles. (To minimize bounce, the truss height is usually increased a few inches.)

You may not even realize that floor trusses are an option. They’re a variation on common roof trusses — the wood structures at the top of a home’s frame designed to bridge the space above a room and to provide support for the roof.

Floor trusses borrow the same engineering principles bridge builders have employed for decades. There’s a very good chance you’ve driven across a Pratt truss bridge in your lifetime. This bridge is designed just like a floor truss, with a flat top and bottom chord and lots of triangles in between.

Just as a bridge can span a river resting on two piers, one on each bank, floor trusses can do the same in your new home or room addition. The ends of the floor trusses rest on the parallel exterior walls. There’s no need for weight-bearing walls in the center of your home. Imagine the possibilities of an open floor plan with those interior walls out of the way.


Floor trusses would be used instead of traditional floor joists. I used floor joists in the last home I built, a Victorian home that had a maze of bearing walls throughout the house because of its traditional design.

Another reason I favor floor trusses is that they make it easier, and thus cheaper, for plumbers, electricians and HVAC workers to install all the necessary utilities in your new home. The open design allows plenty of room to run pipes, ducts and cables.

Drywall hangers love floor trusses, too. The drywall sheets meet on the wide dimension of a 2×4, not a narrow 1.5-inch-wide floor joist.

If you couple floor trusses with factory-built walls, you can minimize construction time and get your house under its roof faster. The precision of these factory-built components is remarkable.

To see how these wood floor trusses work, you can check out the videos on my website at

Tim Carter has worked as a home-improvement professional for more than 30 years. To submit a question or to learn more, visit