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I have a partial kitchen wall I'm trying to tear down. I took out the ceiling drywall and there are long joists running perpendicular to the wall which made me think the wall might be weight-bearing.

The partial wall does not have a double top plate, but the weirdest thing is that the joists are made up of two by threes on the top and bottom with a long thin sheet of plywood between the two, sort of like a long wooden I beam.

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The first picture shows what the interspace of the joist looks like. The second picture shows how the rest of the room requires no supporting beams. The third picture is a close-up of the plywood between the 2x3s seeming to act like some kind of wooden I-beam.

These plywood joists don't end above the kitchen wall like a normal joist would on a weight bearing wall, and the rest of the room is completely open with no supporting walls.

Do you think I can knock this wall down? And not have the place collapse?

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  • It sure sounds like you are knocking out a load bearing wall. Can you give more pictures in different directions and below? This picture doesn't help at all - except shows me you have joists. – DMoore Oct 26 '14 at 6:21
  • I added some pictures, I hope they help. This is an older building, and I've never seen any joists put together in this way. – iopener Oct 26 '14 at 8:04
  • If you made the hole one more cavity larger, into the open span area, and found the same exact specs type joist, wouldn't this be reasonable? Whats that stamp say? – Mazura Oct 26 '14 at 8:24
  • I agree with you, but I think I was stuck in a futile attempt to minimize the amount of ceiling drywall I had to replace. I couldn't make out the stamp at all. – iopener Oct 26 '14 at 8:58
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    "Drywall is the enemy." – Mazura Oct 26 '14 at 9:04
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TJIs of some sort making it virtually certain that the wall is not load bearing. The same joists are holding up the same second story over the same span beyond this wall. enter image description here

If the wall was a properly built load-bearing single-top-plate wall every stud would be exactly under a joist. Its not load-bearing.

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  • Thanks for that... What are TJIs? – iopener Oct 26 '14 at 16:29
  • Wooden I-Beams - Trus-Joist I-something being the progenitor of the product. – Ecnerwal Oct 26 '14 at 23:31
  • 20 minutes with the sawzall (that did not get pinched in the slightest) confirmed your conclusion. Thanks! – iopener Oct 27 '14 at 6:03
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You need to get it evaluated by a qualified engineer. Do not proceed until you have. The stakes are too high to risk it.

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Depends, if they were made by Georgia-Pacific, then:

PDF: Engineered Lumber Quick Guide:

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  • I can't tell if these joists are Georgia-Pacific, but after taking some measurements they are almost exactly comparable to the WI 40s or the GPI 40s, and as the entire room is just over 20 feet wide, the joists don't seem to need any additional support. Am I reading that correctly? – iopener Oct 26 '14 at 9:00
  • You are amazing for finding this by the way :-) – iopener Oct 26 '14 at 9:01
  • By the way the joists are 14 inches high, and in the partial wall one set of studs is 19 inches on center and the other is 16 inches on center. – iopener Oct 26 '14 at 9:03
  • Without even looking at the table, knowing that the two areas are of different construction, I would say that it is indeed a supporting wall. It's up to you to do the math and see if you want to get away with it; whether or not doing so is within spec, deflection in the floor above may increase dramatically. I installed some joists like this on a 24' open span, within spec and it was kinda bouncy. – Mazura Oct 26 '14 at 9:12
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    @iopener - Your joists, as noted from the pictures, are made with lumber flanges not the laminated type flanges. So, if it is suitable to compare to the Georgia-Pacific tables, your 14" high 16"OC joists compare with the WI style for a single span of 22'-03". – Michael Karas♦ Oct 26 '14 at 14:52
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Not that strange, I live in a newer construction home in Minnesota and all of the floor joists are that style. Out at the edges of the house they also added short perpendicular joists between the long ones for additional stability.

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  • Yeah, I think they used to cross braces inside to joist spaces to achieve the same effect here. – iopener Oct 27 '14 at 5:57

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