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How to select a floor truss to limit load-bearing walls in the home you’re building

You’re looking at magnificent floor trusses. These are spanning 28 feet, but you can go greater distances with ease. There’s no need for a bearing wall or beam under them to support the weight of the floor above. (Tim Carter)

Q: Tim, is it possible to build a multistory home with no, or few, interior bearing walls or beams? I’ve looked at lumber span tables, and regular lumber doesn’t seem to be able to do what I want to be done. What are my options, and have you ever solved this problem before? — Stewart F., Portland, Maine

A: You can build a multistory home with no bearing walls. It’s been done for decades. Amazingly, it’s done using regular 2-by-4s to solve the problem! No, that’s not a typo!

Let’s first discuss the span tables that Stewart mentioned. A span table is a chart that shows how far a certain floor joist can span and not bend too much, depending on several factors. The wood species, the grade of the lumber and the height or size of the floor joist are the primary factors taken into consideration when creating the tables.

It's important to realize that different species of lumber have different strength characteristics. When I was building every day, Douglas fir was one of the strongest types of lumber you could buy. Southern Yellow Pine was also very strong. Hemlock, on the other hand, was somewhat weak.

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Decades ago, I used floor trusses made with ordinary 2-by-4s to create the floor of a large room addition for a client. He refused to have any interior load-bearing walls or beams and wanted a floor that was as solid as concrete with no bounce in it. Magic floor trusses solve problems such as these and offer much more to architects, builders and homeowners.

A floor truss is made in a factory where common roof trusses are made. Advanced computer technology designs the exact size and shape of the truss to meet whatever specifications you require.

The end result is a wood floor truss that looks much like large steel bridges that span rivers and canyons. I'm sure you've seen hundreds of these where the horizontal top and bottom members of the bridge are connected by numerous other pieces of steel that look like a bunch of connected letter Ws one after another along the side of the bridge. This design can be done with steel, 2-by-4s and even toothpicks for class science projects!

Plumbing, heating and cooling and electrical contractors love working with floor trusses. They have virtually unlimited places to run pipes, ducts and cables, and allow never having to drill one hole. The center of each floor truss almost always has a wide-open chase for a heating or cooling contractor to install his primary supply ducting down the center of the entire floor from one end to the other.

A floor truss can be designed to span 30 or more feet with ease. The truss manufacturer can build them so strong that there’s no bounce to the floor at all. This comes in handy if you desire a tile floor. Tile and grout can crack if installed over wood floors that are springy and bouncy.

Two or three carpenters can easily move around these giant floor trusses. You don’t need to have a large crane on a job site to set them. Each truss is an identical copy of the one next to it, so the finished floor is flat and smooth with no humps or dips in it. These imperfections are quite common with normal dimensional lumber floor joists.

You can discover lots more about floor trusses, as well as the closest lumberyard near you that can order them for you. Visit:

Since each job is different, these epic building materials are not a stock item you can just go pick up. This is why you’ve probably never ever seen them before. I guarantee you’ll be spellbound when you discover all that floor trusses make possible.

Q: Tim, I hope you can help me. A recent bathroom remodeling job turned into a larger project resulting in a large patch of wall plaster that’s got to be replaced. My contractor’s drywall people have never done plaster repair. How would you fix a 3 foot-by-3 foot hole in the wall if it were your home? I’m tempted to try to do the plaster repair myself. Do you think this is folly? — Ann W., Montrose, Calif.

A: Situations like this had to be part of the inspiration for the children’s book “The Little Engine That Could.” My nickname at home is Dream Crusher, because I often inject reality into family discussions. More often than not in DIY situations, however, I take the opposite tack. I say, “Get a simple plastering trowel out and get to work!” Yes, you can achieve professional results with the right attitude and some guidance.

You’re blessed to be living in an age where technology permits the easy sharing of knowledge. Quite a few professionals have invested vast amounts of time and resources to create excellent step-by-step videos of how to do thousands of projects. I’ve been doing it for nearly 20 years and have more than 650 DIY videos on my AsktheBuilder YouTube channel.

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Kirk Giordano is another example. He’s a professional plasterer who lives and works in the Bay Area. He’s created hundreds and hundreds of videos sharing his hard-earned knowledge about plaster and stucco installation.

Kirk is a great teacher and has several videos that show you exactly how to make a plaster repair such as this. What if I told you that you could have the repair completed start to finish in less than two hours? The plaster you need is probably in a bag at a local plaster distributor not too far from your home. Or you can buy it online and have it delivered to your home.

The special plaster trowel you need with the curved corners is also affordable and readily available. You'll be blown away when you see how easy it is to apply the fresh plaster and trowel it so it's smooth. If you completely botch the job, then just chop it out and try again. But I'm convinced that after watching Kirk's videos, you'll get it right the first time!

Need an answer? All of Tim’s past columns are archived free at You can also watch hundreds of videos, download Quick Start Guides and more.