Question about Fire Block

Old 04-20-18, 06:33 AM
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Question about Fire Block

I am installing some LED lighting on my family room wall. While fishing the cable down the wall, I noticed that there is a horizontal 2x4 blocking the stud bay. I was under the impression that this is a fire block, but I'm not sure. I always thought that fire blocks were comprised of one 2x4 run horizontally. On the left side, there is a 2x4 that is running vertically. It appears to surround metal ducting. Is this something that is providing structural support to ductwork? Would it be okay to drill a 3/4" hole through the horizontal 2x4?
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Old 04-20-18, 08:10 AM
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It could be boxing in a cold air return that was panned into the stud space. If it's cold air you can run a cable through it as long as you caulk/foam around the penetrations when you're done. If it's a supply duct you cannot run through it. If it's part of a chimney or flue you cannot run through it.

If it's just fire blocking you can run through it, but again will need to be caulked or foamed with the fire-rated red stuff.

You might need to do some more surgery on the wall or try to figure out layout of what's above or below this space to identify what's actually in that space.
Old 04-20-18, 08:11 AM
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I don't believe it is supporting the ductwork, but rather enclosing it and providing backing for drywall. It doesn't appear to be fire blocking. Are you asking if it's okay to drill vertically through the horizontal piece from top to bottom? Is this "block" sitting on top of the studs below? If so, I would determine if it's offset to one side or the other or centered. If it is offset toward the duct or centered, you can simply drill down just in front of it and you'll end up inside the wall (because the wall is 3-1/2 deep and that block is 1-1/2"). Drill at a slight angle if the block is centered. If the block is sitting on the near side of the wall, then drill downward at an angle through the face of the block and down through the top plate of the wall. In other words, you don't need to attempt to drill straight down through the entire length of the block. And you obviously don't want to drill through the duct.

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