It’s not always the truss company’s fault…

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It’s not always the truss company’s fault…

Being the truss “junkie” that I am, when I see a job site under construction I just cannot help myself, I have to stop and look. I have learned a lot of great things from seeing it with my own two eyes. On the flip side, I have seen some horrifying ones…like today’s experience.

This is a small 2-story home which has the floor trusses erected, with second floor walls up. The roof trusses have been placed on top of the walls, but not “set” yet.

Now the first thing that caught my eye was the builder had framed their own floor truss gables around the stairway. The truss company did not even include them at all. Is this common for you company? If so, why? Why would you leave out “sellable” product that is required anyway? Floor truss gables are a breeze to build, easy profit.

Looking further, I saw that there was a framed gable end truss directly behind a gable truss. So I had to go look. Seemed like a waste of lumber. Why would the contractor be wasting lumber like that without a good reason? I knew there had to be a logical explanation. The picture below shows what I discovered.

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If you look close, you will see that the frame wall is built on top of the non-structural floor gable truss. Just behind that gable truss you can see the framing built by the contractor thickening the wall width to the inside of the stairway. Why you may ask? Do we see what is wrong with this picture yet? Perhaps a closer look is needed…

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Yes, you are seeing that right. The 3-1/2” wide floor truss is hanging well over 2” off the top of the stud wall. This essentially makes floor gable truss a “wall girder”, carrying the wall and the roof above. Notice the roof truss above, which will be bearing on this wall. So we have a non-structural gable floor truss with 1” of continuous bearing carrying wall and roof loads. The gable truss is not loaded for the actual loads which will be applied, or it would have diagonal webbing and plates much larger than 1.5”x4”. But let’s look further…

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Uh-oh! That looks like almost a 4’ cantilever! Ouch. On this truss, that is around 20% of the span. So we have another issue at hand. Not only is there insufficient continuous bearing on the non-structural truss, now there is a cantilever involved

You may be thinking “How can that be”? Why would the framer build the walls 2”+/- off? Why would they do such a thing? There must be a reasonable explanation. Let’s look down to find out…

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Plumbing! When the plumbing contractor came to do their part, before the slab was poured, their team measured wrong by 2”+/-. The pipes were located. The foundation was poured. Oops!

The contractor comes on site and has some choices:

  1. Shrink the house by 2”
  2. Chop up the slab and fix the plumbing
  3. Ignore it and “keep on trucking”
  4. Call the truss company and get a properly designed girder delivered

Option 1 means the homeowner loses some valuable space on a very small house. Scratch that!

Option 2 means more cost and project delays. Scratch that!

Option 3 means they build an unsafe house and hope the inspector does not notice it.

Option 4 means more cost and project delays. Scratch that!

Now if you are reading this post, that means you are a “truss guy/gal”. It also means you are scratching your head wondering why they chose option 3. If you supplied these trusses, you have done everything you were required to do, yet it was not enough. How many times have we gotten the phone call on something like this and were told it was “our fault”? More than we care to recall.

Now mind you, there were already 2 other flat girders on this job carrying wall and roof loads that were properly designed. Why couldn’t the contractor choose option 4 and add a 3rd?

Let this example show that no matter how good your plans are, your contractor is or how skilled your design team may be, other factors are involved that are beyond our control. Shame on this contractor for choosing option 3. I certainly will not be recommending them to anyone! Let’s hope for the homeowner’s sake that there is a quality, high-integrity building inspector on this project.

Christopher Gould – President

Gould Design, Inc.

10 comments

  1. The proper thing to do when a mistake is found is to correct it and charge back the one that made the mistake in the first place. If the mistake is ignored or worked around it balloons from there and the problems become worse not to mention that the one who made the mistake should be held accountable so the mistake is not repeated somewhere else in another jobsite. Sometimes the biggest mistake is hiring an inexperienced crew to pour the cement or do the plumbing. C);->

  2. There are always new products and ideas being introduced allowing more and more design options for trusses and time-saving ways to frame a roof system. Almost every job can be done with trusses with the right skills and abilities. However like anything there are pros and cons for both sides and comes down to what the builder is comfortable with and what he wants to use on his job. All we can do is try to educate him on the other options that are available and show him what can be done with trusses and the savings that are there to be made.

    1. A skilled designer can work wonders. I think it’s more about what the builder understands. Like any human, complacency becomes a factor. The builder just doesn’t want to learn anything new. How often do you hear “That’s just how we do it”, without any rhyme or reason? They cannot even tell you why. These days, that is kind of like trying to upload the music from your 8-track tape into ypour mp3. It just cannot be done. Life begins 3 steps outside of your comfort zone!

  3. While what you say is very true it has nothing to do with the truss company and every thing to do with the builder. It is/was the responsibility of the builder to ensure that the plumbing was is the correct place prior to pouring the slab in the first place.

    I have seen this exact problem and worse (cutting through the top and bottom chord of a floor truss ) . My solution has always been not to use “gable” style floor trusses to begin with.