Ticking sound in walls

[Jon Wohlgemuth]

I have a ticking sound in my walls when the hot water is on I’m doing a bathroom reno of my master bath and I want to see if I can fix it. I’m not sure whether to go up through the ceiling below or to pull out the subfloor in the area I need to check in the master bath. It’s right by the toilet where I have to pull it up so I’d rather not. There is a second bathroom right next to the master bath that when the hot water is on in there the same thing happens as well. The drain in the master bath is disconnected so I ran the hot water into a bucket and I didn’t notice it happening so I’m thinking it might be the PVC drain? I Was hoping I could attach a video with the sound but I don’t think I can.
Thanks for any help and suggestions.

 

[Reach4]

Filling a bucket does not involve as much water as a shower or bath.
Do you have a tub? What do you hear if you fill the tub with hot?

 

[Sponsor]

 

[Jon Wohlgemuth]

Filling a bucket does not involve as much water as a shower or bath.
Do you have a tub? What do you hear if you fill the tub with hot?

Thanks... So the master shares a wall with another bathroom that has a tub and it the noise happens when the tub is filling or showering. The noise only happens when I leave the water on in the master bath sink. It doesn't happen when taking a shower in master bath for some reason. Not sure if supply lines are different or what. I can kind of hear where the noise is coming from but before I start ripping things out I want to make sure its not a vent pipe and the noise is traveling down from the attic or roof. Is that possible? When I stick my ear to the drywall below it sounds like its right there. Hope this all makes sense.

 

[LLigetfa]

the noise happens when the tub is filling or showering.

If it happens during tub fill then the source is likely the hot supply pipe expanding and rubbing where it goes through wood support members. They make plastic inserts that are meant to reduce the ticking sound. It would be a major undertaking to retrofit them.

 

[Jon Wohlgemuth]

If it happens during tub fill then the source is likely the hot supply pipe expanding and rubbing where it goes through wood support members. They make plastic inserts that are meant to reduce the ticking sound. It would be a major undertaking to retrofit them.

Thanks.. That would make sense but I ran the hot water in the master sink to a bucket actually 2 home depot buckets so a decent amount of water and no sound. Ran the sink in the other shower after and heard the ticking sound. Could it be expansion contraction of the PVC drain?

 

[LLigetfa]

Thanks.. That would make sense but I ran the hot water in the master sink to a bucket actually 2 home depot buckets so a decent amount of water and no sound. Ran the sink in the other shower after and heard the ticking sound. Could it be expansion contraction of the PVC drain?

Then it sounds like you have two separate sources for the ticking sound, the hot supply and the drain. Again, if the tub fill produces sound with no water going down the drain, it stands to reason that the hot supply line is the source of the sound. Mind you, it could also be the increase in weight on the support structure creating ticking sound. Filling the tub with cold water would vet that out.

 

[Terry]

Most ticking in a wall is the drain line, too tight in the hole that was drilled. I sometimes open the walls and cut a bit of wood away from the pipes.
After doing a few service calls like this, I started being extra careful with my drilling. Sometimes drilling a 2/78" instead of my normal 2-9/16" for the shower drains.

 

[Reach4]

If you heard ticking after dumping 10 gallons of hot water from buckets down a drain, that would be drain piping making noise.

For testing, you could also run a garden hose from the water heater drain valve to the drain you want to test for ticking due to thermal expansion.

 

[Jadnashua]

PVC pipe has a fairly high thermal expansion coefficient. IOW, it can change size a fair amount with temperature change. Preventing that from becoming a problem means understanding this, and then building the drain lines accordingly so that they can expand and contract without rubbing, or bowing. Running hot water down the line will cause it to expand, and, a bit slower once that stops, you may hear it rubbing/stopping/jumping (can sound like a tick) as it later cools off again.

Easier prevented rather than stopped later, but the pipe is rubbing on something and you're hearing it as it binds then jumps through that restriction.

FWIW, your water supply pipes can do similar things, but copper's thermal expansion coefficient is much lower than PVC's. Forget the units, but for copper it's 9.8 while pvc is 28, so nearly 3x more expansion per degree.

 

[Jon Wohlgemuth]

Thanks for all the answers... appreciate it. I'm gonna take some drywall out to see what I can do.