what size wall for 4" pipe


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Old 03-07-19, 04:07 AM
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what size wall for 4" pipe

I remodelling and going to install a 4" stack down from 3 floors.
What size wall do I need to accommodate this?
WIll a 2x6 wall be enough? 2x4 is not.
 
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Old 03-07-19, 04:10 AM
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This can be done with two 2x4 walls next to each other. If load bearing you may need to allow a bit of space between them otherwise they can touch.
 
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Old 03-07-19, 04:42 AM
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4" schedule 40 PVC pipe's outside diameter is 4 1/2". So, you will need a wall cavity (the hollow space in the middle not the total wall thickness) at least 4 1/2" deep. More is better in case you do not drill your holes exactly centered in the wall. Also, where your stack penetrates the framing install steel cover plates over the pipe to prevent someone from running a screw into the pipe when hanging the sheetrock.
 
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Old 03-07-19, 05:06 AM
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2x6 is the standard minimum wall thickness for it. The double 2x4 wall is better if any fittings will be coming directly out of it toward the sheetrock. But if fittings are sideways, 2x6 works.
 
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Old 03-07-19, 05:51 AM
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Trying to envision that, what's the problem with a 2x6 and fittings, the angle?
I presumed you would just make a hole and fit accordingly.
 
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Old 03-07-19, 06:10 AM
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Fittings are larger in diameter than the pipe. 4" pipe is 4 1/2" on the outside. A simple coupling will push that to 5" and some fittings have nubs and other bits sticking out that make them even wider. A 2x6" wall can work but you don't have any wiggle room. Once I've seen where it was just too close and the drain pipe made a knocking sound on the sheetrock as it moved slightly when hit by the slug of water from a toilet flushing.
 
 

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