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In my basement, the bearing wall has horizontal blocks between each stud, similar to what you see in this picture:

enter image description here.

There is one place on the wall where one of the blocks was removed to place an electrical box, and another in the bathroom rough-in to make space for the vent stack. What is the purpose of these pieces, and am I safe to remove one to place another electrical box?

  • 2
    Those look like fire stops to me. – alx9r Aug 11 '15 at 18:56
  • Was the bearing wall constructed with the purpose of being finished? If not, firestopping wouldn't make much sense, but individual studs which have nothing attached near the middle to prevent buckling might not be very strong if e.g. two adults were rough-housing in the basement with the wall while moving almost parallel to it. Not such a danger on a drywall-covered wall, but in an exposed bearing wall it very well could be. – supercat Aug 11 '15 at 20:53
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Can't say for sure why they did it in your situation, without knowing a bit more details.

Typically blocking is installed to prevent framing members from twisting or warping, and to stiffen and add strength to the wall. Though it's also common to install blocking, where fire stops are required by code. Blocking can also provide an attachment point for cabinets, chair rail, counter tops, etc. In walls where the studs are spaced further apart, blocking can provide support to the edge of the drywall between studs.

But again, this is all speculation without knowing more details about your situation.

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    Thanks for responding. This is a bare wall in an unfinished basement. My original guess was to strengthen the wall (keeps studs from buckling), but wasn't sure. If it's for this purpose, would relocating the block higher or lower be appropriate? – Eric Andres Aug 11 '15 at 17:42
  • If it's any help, the electrical panel is placed in one of the spaces without a block. My thought is the panel is probably rigid enough to provide the same support as a block. – Eric Andres Aug 11 '15 at 17:43
  • I really can't say for sure without looking over the building codes adopted in your area. It could be that the panel meets the requirements that the blocking was meant to fill, or that somebody removed the blocking to fit the panel without knowing what the blocking was for. – Tester101 Aug 11 '15 at 17:47
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    Makes sense. Thanks. I'll check with my building dept. – Eric Andres Aug 11 '15 at 17:48
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    @BMitch The OP said "similar to what you see in this picture", which I take to mean that this is not a photo of their wall. As it's unclear what their specific wall looks like, or where they live, I can't be sure what the purpose of the blocking is. – Tester101 Aug 11 '15 at 23:46
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The blocks are known as Dwangs or Nogs here, and was confused about what blocks you were asking about. But they are used for stiffening the wall and attaching drywall, as well as mounting points for basins etc. Not heard of them being used for firestopping, and does not make a lot of sense to me.

Recommendation from BRANZ (local building regulation association) is a nog every 800mm of stud - i.e. at least one per story. When one was removed to fit a power board into an internal wall I was working on, the builder fitted one below and above the panel to maintain strength. Makes sense to do the same here, as any twisting or buckling of the studs would cause the drywall to crack.

https://en.wikipedia.org/wiki/Dwang

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Typical of firestopping, so that (when sheeted with drywall) flames cannot run the full height of the wall inside the stud bay. It would be better to move (up or down a few inches), rather than remove the blocking, for that reason. While it may be unfinished at present, the builders presumably intended that it be ready for drywall if/when you or some other owner chose to finish the basement.

Of course, it would also be better to have the electrical planned out so that the framing can be built to accommodate it in the first place, but the world isn't perfect.

Still, I'd put new blocks in place above or below the outlets that caused them to be removed, and fire-caulk any holes required in the blocks for wires to run through.

  • Firestopping would make sense in this situation. I'll just plan on moving the block, and the inspector will let me know if I messed it up :) – Eric Andres Aug 11 '15 at 17:51
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    +1, looks like fire blocking to me as well. Fire blocking is a requirement when walls exceed 8', and is typically placed somewhere in the middle of the wall. The blocks can be moved up or down as needed as long as the longest unblocked span is within code (it's best to keep it near the middle of the wall to split the space roughly in half). – BMitch Aug 11 '15 at 23:20
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According to our building code: (5) Where load-bearing interior walls are not finished in accordance with Sentence (2), blocking or strapping shall be fastened to the studs at mid-height to prevent sideways buckling.

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    Good Answer! - Can you edit in your location in reference to the building code? – Chris Cudmore Sep 26 '18 at 13:52
  • Welcome. Knowing what "Sentence 2" means would make your answer even better. – Daniel Griscom Sep 26 '18 at 17:13
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Nogging in the UK. These do the same job as herringbone bracing in between floor joists i.e. they stiffen up the wall and also stop the studs twisting (in theory).

They are commonly placed as in the picture but also either side of the marked line. Staggering then thus makes for easier nailing (straight instead of skewed).

If I remove a nogging I'd try to replace it above and below. Sometimes we turn one through 90 degrees to fit a outlet box, but that's not the best practice.

Additional runs of noggins are a good idea at the top of cabinet heights in kitchens/bathrooms and I also add one at counter or worktop height. Special furniture can also benefit from additional nogging such as toilets/basins/anything else that needs hanging from the wall!

On better quality jobs I put two additional runs through (dividing the height into 1/4's).

Never heard the fire blocking part, must be peculiar to the region. Fireproofing in the Uk typically goes in between floors and around penetrations etc. One would imagine that if the fire has reached the middle of the wall then that floor is in serious trouble anyways.

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I doubt the blocking is fireblocking. Fireblocking is required at 10’ intervals. (See ICC R302.11)

It could be: 1) shearwall blocking or 2) vertical load blocking.

1) Because the block is placed EXACTLY in a straight line, they could have laid it out for plywood to lap half-way onto the blocking. However, I doubt that too, because they don’t have the proper floor anchors in the slab to transfer that much load.

2) When applying large vertical loads, the member (post or stud) tends to buckle...especially in the “skinny” direction. One way of keeping the member from bending is to install blocking...thus reducing the apparent length of the member (post or stud).

Another method of keeping the studs from buckling is to install a wall finish. This works for low to medium loads, but not for high or extreme loads.

Perhaps no wall finish is currently scheduled so blocking is required.

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