"Dripping" Noise in ABS drain pipe

[Josh4trunks]

So after more investigation, I am fairly certain I have freed the 90 degree bend at the the top plate. But, checking the vertical potion of the pipe I can clearly feel several feet of it are pushing up against the drywall.

So my current theory is the vertical pipe is slightly pushing against the drywall. When I drain a hot bath/shower the horizontal portion of the pipe expands and pushes the drywall even more, which in reaction pushes back more. These forces translate to shear forces in the coupler portion of the 90 degree bend. As the pipe cools stress is released in bursts creating popping noises.

I made another hole lower in the wall, this time a little more visible (but still in my pantry) where I can access more of the pipe and started the fun job of sanding down the backside of the drywall (paper) to relieve pressure on the pipe.

 

[Jeff H Young]

josh4trunks , I think you have te right Idea Im not sure its the drywall but thats the issue the drain pipe contacting and moving against something

 

[Sponsor]

 

[yasonjim]

So after more investigation, I am fairly certain I have freed the 90 degree bend at the the top plate. But, checking the vertical potion of the pipe I can clearly feel several feet of it are pushing up against the drywall.

So my current theory is the vertical pipe is slightly pushing against the drywall. When I drain a hot bath/shower the horizontal portion of the pipe expands and pushes the drywall even more, which in reaction pushes back more. These forces translate to shear forces in the coupler portion of the 90 degree bend. As the pipe cools stress is released in bursts creating popping noises.

I made another hole lower in the wall, this time a little more visible (but still in my pantry) where I can access more of the pipe and started the fun job of sanding down the backside of the drywall (paper) to relieve pressure on the pipe.

Did you end up fixing the issue? I'm about to open up my walls to fix the same drain expansion ticking but am afraid it'll turn into your situation where nothing works.