Loud bang in drain pipe with movement

[edee_em]

An update to my loud banging drain pipe. I posted this earlier but no one has replied. Today I noticed the 3" drain pipe was pushing up against the subfloor under the wall plate. If you look at the photo you can see how far right they cut the bottom plate to get that pipe in. I chipped away at it as best I could and when I got the last piece out the drain pipe moved a lot more freely.

I asked my son to flush the upstairs toilet that is coconspirator to the problem and I could see the vertical drain pipe jerk over to the right and make the banging noise. There never was any support on this pipe. I'm guessing because it is vertical. I spray foamed the entry at the top plate to see if that would help (it didn't).

My plan is to spray foam the drain pipe in place where it enters the bottom plate of the wall. Any opinions on whether this will steady the drain pipe or should I do some support half way down as well? Also, any feelings on spray foam as a method of support for a 3 " drain pipe?

Thanks

 

[frodo]

................

 

[edee_em]

Thanks Frodo. I'm guessing by your provided solution you would be against the foaming option?

secondly, you show the 2x4" support with strap. Would you have the strap come through the 2x4 by drilling a couple of holes or would you have the strap come from underneath/over the top?

 

[edee_em]

Now I'm becoming that pest like your ant scurrying around your avatar. Just that I know the picture limits exact placement of the 2x4 and strap so would you put it half way up/down the wall or closer to the bottom or right at the bottom?

 

[frodo]

try and get it as close to the wall as possible

over the top pulling the pipe tight. if you angle the nail you can tighten the strap as it is driven in

or use a screw

 

[edee_em]

Don't think I asked the question correctly. I was asking where the 2x4 should be installed: near the top of the wall (out of the photo), the middle (out of the photo) or near the bottom where you have drawn it. Asking because the photo doesn't show the whole length of the drain pipe.

 

[frodo]

the horizontial run of the pipe should be supported every 4' according to code
it keeps the pipe from sagging and getting a belly in it

the easiest way to support it is to put a 2x4 under it and let it ride on the 2x4

 

[Mr_David]

Don't think I asked the question correctly. I was asking where the 2x4 should be installed: near the top of the wall (out of the photo), the middle (out of the photo) or near the bottom where you have drawn it. Asking because the photo doesn't show the whole length of the drain pipe.

Put it where ever you think is best to secure the pipe from rattling.

I would cross the strap over the 2x4 to hold it better from side to side movement.
If it is to tight it my develop a tick as the pipe expands and contracts.

 

[Mr_David]

the horizontial run of the pipe should be supported every 4' according to code
it keeps the pipe from sagging and getting a belly in it

the easiest way to support it is to put a 2x4 under it and let it ride on the 2x4

tilt your head to the left .

 

[frodo]

OH!!!!!!!! OPPSY. I'm all backwards,

face red

 

[edee_em]

Sorry guys! The photo, for some reason, was rotated when I attached it. Mr_David has the solution, but don't stare at it too long!!