"Dripping" Noise in ABS drain pipe

[Josh4trunks]

Hello,
So I have a "dripping" noise coming from an ABS drain pipe that goes from a 2nd story bathroom, horizontal maybe 10-20 feet, then vertical to the concrete slab. I cut open the wall in my pantry where the noise was loudest and found everything dry and realized the noise is actually coming from the pipe itself. The best way to reproduce it is to fill up the upstairs bathroom with hot water, then drain it. I can feel the ABS pipe get warmer, and can tell it lengthens because it used to push on a metal nail plate next to it, then the "drip" noise starts happening.

I assumed the pipe rubbing on a side was the problem based on https://terrylove.com/forums/index.php?threads/abs-pipe-noise.10950/#.
I used various tools: osculating saw, hand saw, and sand paper to make sure none of the wood from the top plate is touching it. On the far side of the bend where it would touch the metal plate I sanded the elbow down so it no longer rubs. Even with a full hot bathtub being drained, the pipe no longer touches any sides. But the noise persists! It's like the pipe itself is flexing and causing noises at the 90 degree joint.

I'm at a loss at what the solution is? If I have a plumber come over and replace the piping / elbow accessible in the pantry could that make a difference? Any chance it was a bad / old glue, the home was built in 2002.
My other idea is save on having a plumber over and just fill the accessible area with Owens Corning 703 insulation and see if the noise is dissipated enough to not be noticeable.

Thank you for the help!

 

[Breplum]

Replace the ABS with cast iron. We never use plastic for drains above the first floor for this very reason.
On the other hand, especially out where you are, where higher density, quickly and economically-built housing is the dominant paradigm, plastic drains are the rule.
Sure, if you want to frame up a 2 x 8" thick wall with acoustic absorbing barriers, then add putty pads, that could work (or not).

https://www.amazon.com/ATS-Acoustics-Putty-Pads-Acoustical/dp/B006C25ZKA

 

[Sponsor]

 

[Terry]

Expansion and contraction, normally against the wood or a strap. I don't think it's just the pipe making the noise though. Not the ticking at least.
Insulation does help some though.

 

[Reach4]

Is this ticking more after a hot shower, or after a toilet flush?

 

[John Gayewski]

How do you fill your bathroom with hot water? I feel like it would leak through the door at least.

Hello,
So I have a "dripping" noise coming from an ABS drain pipe that goes from a 2nd story bathroom. The best way to reproduce it is to fill up the upstairs bathroom with hot water, then drain it.

The dripping noise is the pipe. Insulation could help.

 

[Jeff H Young]

tremendous cost but if the noise bothers you repipe in castiron . We used to pretty much run cast on high end homes.
Most homes its too expensive but places like san fransisco the houses are so expensive and a lot of people got money to burn on things they like. the ticking is often from abs going through tight holes and a few other workmanship issues. Dont know if PVC charectoristics are the equally disappointing with noise

 

[Josh4trunks]

Replace the ABS with cast iron. We never use plastic for drains above the first floor for this very reason.
On the other hand, especially out where you are, where higher density, quickly and economically-built housing is the dominant paradigm, plastic drains are the rule.
Sure, if you want to frame up a 2 x 8" thick wall with acoustic absorbing barriers, then add putty pads, that could work (or not).

https://www.amazon.com/ATS-Acoustics-Putty-Pads-Acoustical/dp/B006C25ZKA

Not gonna repipe my house anytime soon, lol. I'll keep that in mind if I ever have a house built though.
Thanks, will probably buy the putty too.

 

[Josh4trunks]

Expansion and contraction, normally against the wood or a strap. I don't think it's just the pipe making the noise though. Not the ticking at least.
Insulation does help some though.

I can confirm it isn't rubbing because I can slide a piece of sand paper all the way around the pipe without snags, even when the pipe is warmed up from a hot bath/shower. I was totally convinced rubbing was the cause, but after completely freeing the area with the noise, I think it is just stress/flexing at the joint.

Another theory I have is the snag is somewhere else and the sound is traveling through the pipe, and is heard at the 90 joint. But I doubt this theory is true.

 

[Josh4trunks]

Is this ticking more after a hot shower, or after a toilet flush?

Definitely a hot shower/bath. I don't think a toilet flush is enough to trigger the "ticking".

 

[Jeff H Young]

My house does the ticking when running hot water down a particular drain . Its a very common issue mostly ignored because people don't usually want to open up walls to repair

 

[Reach4]

Definitely a hot shower/bath. I don't think a toilet flush is enough to trigger the "ticking".

So thermal expansion/contraction, as Terry said.

If you can get sandpaper thru the hole, maybe you could slip a piece of plastic that will lubricate the path a bit. I am thinking of maybe the plastic that we used to use on overhead projectors, or even a bread clip. It seems to me that even if you could fit sandpaper in, maybe you deflect the pipe to insert sandpaper, and the pipe may not be centered in that clearance hole.

Holding the pipe during the ticking could let you maybe, by feel, isolate the sound source better than locating with your ears.

 

[Terry]

I have opened walls for customers and cut wood out around pipes that run vertically though top plates. Sometimes a slightly crooked hole pinches the pipe. As it expands with hot water and gets longer and wider, it's not so obvious, but when it contracts, that's when it's at it nosiest.

Do a few, and I found myself using larger drill bits for top wall plates.

 

[John Gayewski]

How did this thread turn into fixing expansion and contraction noises when the complaint was dripping sounds which is definitely being heard through the pipe? There's no complaint of ticking or squeaking. We're talking about deadening the sound in general.

 

[Terry]

How did this thread turn into fixing expansion and contraction noises when the complaint was dripping sounds which is definitely being heard through the pipe? There's no complaint of ticking or squeaking. We're talking about deadening the sound in general.

There can be noise as it drains, and noise that can happen after the draining has stopped. He hasn't clearly told us when the noise starts and the noise stops.
Is he hearing water flowing? Or is it expansion and contraction?
If it's just water being dumped, then yes, on the insulation and/or replacement with cast.

Does it only happen with hot water? Or is it also cold water?

"The best way to reproduce it is to fill up the upstairs bathroom with hot water, then drain it."

 

[Reach4]

How did this thread turn into fixing expansion and contraction noises when the complaint was dripping sounds which is definitely being heard through the pipe? There's no complaint of ticking or squeaking. We're talking about deadening the sound in general.

I initially assumed dripping, but dripping sound would not normally follow a hot shower, I would not think. So I then suspected a ticking sound vs a dripping sound.

Not to say that a shower could not cause a dripping sound. And to that end, I guess I would test by running the shower on cold for a while (if the controls allow that).

 

[Josh4trunks]

My house does the ticking when running hot water down a particular drain . Its a very common issue mostly ignored because people don't usually want to open up walls to repair

It was fairly loud for me and I wanted to make sure there wasn't a leak. I was able to access the pipe in a pantry so drywall repair isn't a big deal. But if I had to cut into visible drywall I would have been more hesitant. Whenever I repair drywall I can never get the texture to match, lol.

 

[Josh4trunks]

So thermal expansion/contraction, as Terry said.

If you can get sandpaper thru the hole, maybe you could slip a piece of plastic that will lubricate the path a bit. I am thinking of maybe the plastic that we used to use on overhead projectors, or even a bread clip. It seems to me that even if you could fit sandpaper in, maybe you deflect the pipe to insert sandpaper, and the pipe may not be centered in that clearance hole.

Holding the pipe during the ticking could let you maybe, by feel, isolate the sound source better than locating with your ears.

Will triple check today, location of noise by feel and that it really isn't touching anything while ticking is happening.
I can even borrow my wife's stethoscope and see if that helps, though I don't know how to use it...

 

[Josh4trunks]

How did this thread turn into fixing expansion and contraction noises when the complaint was dripping sounds which is definitely being heard through the pipe? There's no complaint of ticking or squeaking. We're talking about deadening the sound in general.

It sounds like dripping, but as far as I can tell there is no visible leak. And the noise is happening at a 90 degree before going down from 2nd story to slab. My current though is the noise is actually creeking at the joint. I can sometime reproduce the noise by just trying to twist/bend near the joint.

 

[Josh4trunks]

There can be noise as it drains, and noise that can happen after the draining has stopped. He hasn't clearly told us when the noise starts and the noise stops.
Is he hearing water flowing? Or is it expansion and contraction?
If it's just water being dumped, then yes, on the insulation and/or replacement with cast.

Does it only happen with hot water? Or is it also cold water?

"The best way to reproduce it is to fill up the upstairs bathroom with hot water, then drain it."

I definitely hear water flow/gush after a toilet flush or bathtub drain. But I figure that was to be expected, my main concern was the annoying ticking noise that persists after a hot bath/shower.
I ordered some 2" Owens Corning 703, which I was going to use to build acoustic panels eventually. So I'll just sacrifice one of the pieces to insulate around the pipe. I'll also pick up some QuietPutty and put it around the joint itself and see if that makes a difference.

So on the plus side, once I get the insulation, even the gushing noise should be lessened a bit.

 

[Terry]

Ticking after using hot water is usually the pipe binding going down through a wood plate.