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I have a diagonal brace running across an interior wall in the basement, and it even goes partially into the floor concrete. Is this meant to be permanent, or was it supposed to be removed during construction?

I want to finish the basement and put drywall there, but this obviously gets in the way. What are my options for dealing with it?

(Click images for larger views.)
Top of the brace Bottom of the brace goes into floor

Nail locations. 3 nails into the beam at the top, 2 elsewhere:

Nail locations

Brock Adams
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Egor
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    Leaving that there for the concrete pour shows a somewhat distressing lack of attention to detail on the part of the contractor. You might consider looking around to see what other surprises they've left behind. – Eric Lippert Sep 05 '18 at 21:58
  • Yeah, not sure how they missed it. I'll look around some more, although we haven't noticed anything serious in the 2 years we've lived here. The previous owners did replace all light switches with motion-sensitive ones and didn't bother grounding any of them, though. – Egor Sep 05 '18 at 22:24
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    Is the bottom plate *submerged* in the slab? – DJohnM Sep 06 '18 at 04:47
  • @DJohnM yes, there's about half an inch of it above the concrete. – Egor Sep 06 '18 at 06:05
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    @Egor Wood should never touch concrete. Embedding a 2x4 in a concrete slab is ridiculous. Concrete gets wet, moisture goes into the wood, wood rots. – isanae Sep 06 '18 at 06:32
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    Can you `git blame` that brace? What does the commit message say? Do you have a unit test for that staircase and beam above? In all seriousness, that brace certainly is not transferring load to the floor but it _might_ be dampening oscillations when someone traverses those stairs. – dotancohen Sep 06 '18 at 07:13
  • @Egor if you're intending to drywall (gib) this wall, then now's the perfect chance to add bracing before hiding it away. Same goes for running power or data cable or whatever. It'll be harder to do later. – Criggie Sep 06 '18 at 11:07
  • @EricLippert - this looks to me to be a case of owner-made uninspected changes. Perhaps the basement floor cracked and the owner decided to pour a layer of concrete over the existing slab to hide the problems. – Bob Jarvis - Слава Україні Sep 06 '18 at 11:53
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    @isanae Never say never. Pressure-treated wood can touch concrete. – MonkeyZeus Sep 06 '18 at 15:01
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    @isanae &MonkeyZeus - and this does look to be PT by the injection gouges down the narrow side. The color is not what I expect but color varies by manufacturer and treatment material. – Tim Sparkles Sep 06 '18 at 17:09
  • @isanae Don't the bottom plates of all basement walls just sit directly on top of concrete? From what I've seen and read, people just nail regular 2x4 to the slab (admittedly not submerge though). BobJarvis I don't think so. The floor is uniformly painted and level everywhere, from this submerged plate all the way to the exterior walls and under boiler, heater, etc. Also, all the bottom plates around the stairs are submerged like this, but the ones against the exterior walls are not. Those just sit on top. – Egor Sep 06 '18 at 18:10
  • @Timbo you are correct! I found the blueprints for the house and the basement layout has a note "PWF bottom plate req'd on walls around stairs (no poly)". Presumably PWF is "permanent wood foundation", which google says is used for high moisture and ground contact projects. – Egor Sep 06 '18 at 18:28
  • Can you contact the builder and ask them? – Dawood ibn Kareem Sep 06 '18 at 20:13
  • I wouldn't put pressure treated anywhere inside a house. For the bottom plate, just a regular 2x4 on the concrete with a sill gasket in between. – isanae Sep 06 '18 at 20:15

3 Answers3

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Yes, you can remove the brace because:

  1. The wall is non-load bearing (not carrying a load)
  2. The diagonal brace is not secured in a manner to transfer any load at the top or bottom
  3. The diagonal brace is not secured to top plate
  4. The diagonal brace is not secured significantly to vertical stud...the picture cuts off a portion of the brace that crosses the stud so I’d verify that
  5. The diagonal brace is singular
yoozer8
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Lee Sam
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  • Does "singular" mean that it only attaches to one stud? If so, it's not singular. It's attached to the thick load-bearing beam at the top with 3 nails, 2 studs with 2 nails each, and the bottom plate with 2 nails (visible in second picture) – Egor Sep 05 '18 at 16:17
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    I agree with all of the points you mentioned but would you be able to elaborate as to why a brace would have been used like this at all? I cannot identify its original purpose. – MonkeyZeus Sep 05 '18 at 16:27
  • @Egor I used the term “singular” because the OP said there was only one diagonal brace. – Lee Sam Sep 05 '18 at 16:32
  • @LeeSam I am the OP, I was just clarifying what singular means so that I could verify. In that case yes, it's the only diagonal brace in the entire basement. I added another picture also. – Egor Sep 05 '18 at 16:33
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    @MonkeyZeus Often when framing is formed on the ground (slab) and then stood up in place, a temporary diagonal brace will be installed to keep the studs plumb, especially until the gypsum board can be installed. – Lee Sam Sep 05 '18 at 16:35
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    @Egor The additional picture shows no special fasteners (bolts, plates, etc.) holding the sole plate to the slab. Therefore, I’m even more sure the diagonal is temporary. – Lee Sam Sep 05 '18 at 16:39
  • Thanks, you've convinced me. I'll just pry it off and put the drywall up. I guess the drywall will provide some measure of bracing anyway :D – Egor Sep 05 '18 at 18:46
  • @Egor Yes, 1/2” gypsum board installed with fasteners at 8” o.c. Will give you a shear (lateral) load rating of about 200 lbs. per linear foot. BTW, I don’t want you to think I didn’t think about the nail heads used to secure the diagonal brace, but most builders will use a “double headed” nail. It’s easier to remove later, but because there is only one brace, I doubt the builder would change his nail pouch for just a few nails. – Lee Sam Sep 05 '18 at 19:18
  • @Egor: In case it is not clear from the answer: we know that this is not load bearing for several reasons, but the most obvious is: load-bearing walls usually bear loads by spanning many joists, and this wall sits under a single joist. – Eric Lippert Sep 05 '18 at 22:01
  • @EricLippert My understanding was that this is a load-bearing beam, which in turn supports many joists. Is that not the case? My entire house rests on 3 such beams, plus the outer concrete basement walls of course. – Egor Sep 05 '18 at 22:06
  • @Egor: In that case the beam is likely supported by posts, which will be considerably stronger than that wall! That said: I have a load-bearing wall in my house in precisely that same place, at the bottom of my basement stairs; I had it installed because adding a bathtub two floors above it led to a chain of events too tedious to mention in a comment that made the house unsound. Of course it is much stronger than the example you've shown, and is reinforced against sheering in an earthquake, which we have here in Seattle. – Eric Lippert Sep 05 '18 at 22:07
  • @EricLippert Right, I do have metal posts supporting the beam and I didn't think the wall was load-bearing but wasn't sure if that matters for a diagonal brace. As far as I can tell it would still work as intended (ie prevent lateral movement) whether it bears any load or not. – Egor Sep 05 '18 at 22:14
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    @Egor - This answer is, in my opinion as a structural engineer, wrong. See [Brock Adam's answer](https://diy.stackexchange.com/a/146516/38529) – AndyT Sep 06 '18 at 13:39
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That wall is load bearing; it is helping to support the stairs and that landing.

As such, it can be subjected to significant load (think two 250 lb guys, plus heavy furniture, for starters).

More importantly, it is subject to lateral impulses from people and things going up and down the stairs so it should have lateral/diagonal bracing to help stop "rhombusing".

Such bracing will give the stairs a solider feel and also reduce cracking/popping in the sheetrock.

There are a variety of metal bracing products you can use, but it would probably be sufficient, in this case, to nail 5/8's plywood to the backside of those studs (in addition to the sheetrock on the front side.

I'd also use some steel L-straps on the other 2 landing supports (if there's not already something there).

Brock Adams
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  • You forgot about the stringers. In order for the landing to move, it would have to come uncoupled from the stringers. Likewise, there’s no diagonal brace in the opposite direction for those stringers/landing. – Lee Sam Sep 06 '18 at 14:06
  • If a sheet of drywall is glued to those studs, I think it would provide substantially more lateral bracing than a single nailed-in 2x4 ever could. – Eric Petroelje Sep 06 '18 at 14:12
  • @LeeSam, the stringers do provide some lateral bracing but not enough. An easy rule is to look for closed triangles of support. There is no such triangle formed with the top stringers and the landing. – Brock Adams Sep 06 '18 at 16:48
  • The top plate is nailed to the 4x10 beam above it. Can it actually move laterally without the brace? The beam runs across the width of the house, supported on both ends by the concrete foundation and in the middle by 3 spaced out steel pillars (you can see one of them in the picture). Also, could I just change the orientation of the brace and move it to the other side of the wall? Presumably it would work about the same, and I don't plan to develop the space under the stairs anyway. – Egor Sep 06 '18 at 18:37
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    @Egor, it can move (and that beam can move relative to the basement floor, over time). Not enough to be a safety hazard, but enough to contribute to creaks, cracks, and a "springy" feel -- especially as the house gets older. I would discard that 2x4 and untreated wood in contact with cement is a time-bomb of rot and/or infestation. Use the plywood and the drywall. That will give much better stability than a 2x4, and be less intrusive. – Brock Adams Sep 06 '18 at 18:49
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    Thanks! Sounds good. I found blueprints for the house and it says the bottom plate around the stairs is PWF lumber. It does look a little different on closer inspection, has a bit of that greenish pressure-treated tint. – Egor Sep 06 '18 at 18:59
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It is/was a temporary brace, it is safe to remove it.

10-10-2020 EDIT

During the fabrication of the wall, or before the floor system was added overhead the brace was added to stabilize that small wall section, perhaps before the beam was added. The beam in the picture, typically goes from foundation wall to foundation wall, although there can be many exceptions. Still, this hold true... the floor system is now in, that in itself is a huge brace with al the plywood set to the joists that are tied to the beam. Even if the beam that is over the wall in question was not tied into either wall, the floor alone would not allow the beam to move, and therefore the wall in question to rack.

If there is a concern for this non-bearing wall to move or shift or whatever.... and it is a non bearing wall because of the beam over it and a steel post beside the wall to support the beam..., albeit short, the diagonal of the stair carriage WILL hold the center of the studs sable if the carpenter who set the stairs did his job and fastened them to the framing the way he should. The landing does the rest.

As a mention, the concrete floor has a leveling layer of concrete over it. Not only the end of the diagonal in in the floor, the plate it is nailed to is in the floor as well, by about 3/4".

Jack
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    what could possibly go wrong... – Jeffrey Sep 05 '18 at 14:44
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    @Jeffrey: if that brace is mission-critical, then that house is going to fall down any moment for dozens of other reasons. – whatsisname Sep 05 '18 at 17:37
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    @whatsisname agreed. But, my point was about the answer's format. A simple "it is safe to remove it" doesn't quite cut it, because, to the uninitiated, the same answer could be given without the justifying reasons explained. – Jeffrey Sep 05 '18 at 18:50
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    How do you know it's temporary? How do you know it's safe to remove it? Without explanation, your answer has no more value than somebody posting "OMG don't touch it! It'll bring the house down!" How would the asker know which of those two contradictory answers was right? – David Richerby Sep 05 '18 at 23:25
  • I see Lee Sam did it right. – Jack Sep 06 '18 at 06:40
  • Since my answer was so short, I figured I better elaborate a bit more. – Jack Oct 10 '20 at 18:24