Oh yeah, I forgot to mention about the valve.

Its a new house, so when I heard the noise, I asked builder about it at the time of closing. At what I was told that, the noisy valve is on wall without insulation. And other two have insulation. So they reassured me that there is nothing wrong with the valve itself. And it does function normally.

I hope you live in a climate with no freezing weather, what with having shower plumbing on outside walls, insulation or not!

My thinking is that Great Stuff would be the wrong thing for this, as it hardens and sticks to things. It would gum up the plumbing, need to be cut away if any work ever needed to be done, and might even forceably move any pex plumbing lines you may have. If I wanted to insulate that wall, I would look into using soft insulation batts that can be removed if the pipes need work. This would probably give you better sound insulation, as well. What is on the other side of the wall from the shower plumbing? If it is a hall or other living space, would it look okay to have an access panel? If not, a drywall patch and paint is your answer.

Fiberglass doesn't provide much in the way of sound insulation. And it would require opening the wall.

Does the faucet backing up to the kitchen make more noise on the bathroom side than the others do on the bathroom side? (I'm trying to determine if the difference is that the builder added insulation or if there's an issue with the valve).

If you use expanding foam, know that it will stick to everything. You probably aren't going to be opening your wall anytime soon, and when they do they will need to cut the foam away. I don't know that it's a big problem.

I would do what you are talking about - and I would start at the valve area and work my way up and down about every foot. Do know that the foam expands over about 10 minutes so you might want to empty one can and then give it time to expand.

Buy a stethoscope and plant it on the walls right next to all three shower valves, or right on parts of the valves or other plumbing to see if they make similar noise.

I've used spray foam for several tasks, and its not very easy to control where it goes. There are also two types of foam, the Gaps and Cracks that you linked to, and Window and Door foam that has much lower expansion rate.

When first spraying it, the foam appears to expand slowly, so most folks spray a little more. Then the activator catches up and it continues to expand for several more minutes. Wet foam sticks like glue to every surface, and it goes in every direction you don't want it to. I still use it for fire block and to fill in around windows and door frames, but I use the low expansion Window and Door foam and only spray a little at a time.

Bruce

Its a new house, so when I heard the noise, I asked builder about it at the time of closing. At what I was told that, the noisy valve is on wall without insulation. And other two have insulation. So they reassured me that there is nothing wrong with the valve itself. And it does function normally.

Wrong. The noise is most likely due to water hammer. This is a plumbing design issue and the builder is trying to get out of it, probably to avoid paying a plumber some $$$ to fix it. Click on picture below to enlarge it.

I am thinking the OP means more of a buzzing kind of noise related to continuous water flow, but we'll see.

Thanks a lot for all valuable information.

Actually I noticed one thing last night, when water is flowing thru the down spout, it makes more noise than when water flowing thru the shower head.

@nancyinmich

Oh yes, I did not even think about that. The reason I thought about the spray foam is, it could expand and fill in the gaps, and I just have a make a tiny hole to spray. But I believe, if I have to install insulation batts, I probably have to cut the drywall, right? The other side is hall, and the walls have texture, (which I don't like even a bit), so it would be hard to cover it all up. :( How about the loose fill insulation? I have watched videos about this. But I am afraid, the insulation may be fill in all the gaps, especially with the water valve.

@Jake

The other two bathrooms are very silent, both from the bathroom and the other side. Again, likely because of insulation. The bathroom that makes noise, the sound is loud both in side bathroom and other side too, which is hall/kitchen. And this bathroom is right in the middle of the house, so the sound is also audible from the living room. If you think there is some problem with the valve itself, how can I narrow it down? Does it leak water inside the wall? Shower works fine with good pressure like other bathrooms.

I also wish I would not have to open the wall anytime soon. If not the spray insulation, what other insulation would you suggest?

@ionized_gw

That's a good place to start.

@Bruce,

Since I want to fill up the space between two studs, I was thinking of using the gaps and cracks. My idea is to , make two small holes, one below the valve, and one above the valve. First spray below then valve, and then spray above the valve. I don't plan to full up the entire space between the studs, but just give enough insulation around the valve to make it quite and sound proof. I am still trying to figure out if the valve is bad, or is it just insulation like my builder suggested.

@Austin Air companie

Thanks for your input. What's the best way to figure out if the noise is because of the water hammer? It doesn't happen in other bathrooms. Also, the noise is worse when water flows thru the down spout compared to water flowing thru the shower head. Could it be because if the valve?

Hammer is usually used to refer to a discrete thud that is produced when water stops flowing when a valve is shut off. The momentum force of the stopping water produces it. Sound is produced by flowing water when turbulence is generated. The sound can get pretty strong because you are hitting resonance frequencies that concentrate the power. Think of the opera singer breaking the crystal sort of thing. These can be serious engineering problems because if not managed properly they can crash a bridge or break a driveshaft in a car or truck. Possibly dangerous, but more often just annoying, you've probably hit similar harmonics with particular tire or car-pavement combos. (I vividly remember driving a truck-trailer combo on a long stretch of OK I40 decades ago unable to go over about 45 mph. That was partly because the truck was not fast enough to get "above" the resonant frequency of the vehicle on the concrete pavement joints.)

If this annoying shower is making a sound that the other two do not, there is something different about this one. The question is, are the same sounds being generated by all three valves and the sound different because of the different location, or is there something inherently different about the plumbing parts or arrangement. If you put a listening device right on the plumbing, you have a better chance of isolating the source of the "problem". If you listen directly to the knob on your mixing valve and they all sound the same, something outside of the valve and remaining plumbing is responsible. If that valve talks to you differently, the wall probably does not make the difference, but the valve or other plumbing does. You might be able to fix this by just swapping the internal parts of the valve. Your other valves are identical so swap them around first. If that fixes it, great. If the problem moves, You might need new valve guts and I'd contact the valve manufacturer.

bridge resonance

If you use that foam, a plumber who may need to eventually replace that valve will curse your name to the 7th generation.

Covering up a noise using sound blocking material is not a fix.

water hammer covers a wide assortment of plumbing noises, most of which are directly related to the 'design' of the plumbing system... you know the invisible crap you take for granted that make a plumber worth what you pay him.

I am not a plumber, but excessive noise from running plumbing is in 'no stretch of the imagination' not a bigger problem later on.

Turn the screws on the builder. Do not accept anything less than what the other plumbing fixture noises are when you operate them.

'squeaky wheels get the grease.'

what kind of plumbing system is it? PEX? (as in food for rodents later on?) --- yeah I've seen every gimmick there is.

I don't really want to get too deeply into a "water' match no matter what kind of water, if you get my drift. In my view this is more likely a cavitation problem than water hammer. Sure, it can be serious. Most likely, the pipes or something else will have a shorter life if any bad effects are ever seen beyond the noise.

I certainly don't disagree with the fact that the builder should be pressed on this. Coming into the discussion with some evidence puts you in a stronger position. While swapping out the valve guts might be too much, I think that having a listen to the valve through the mix knob, if practical, would be good thing. Heck, if the thing and the listener's ear are the right shapes, you might not even need a stethoscope. The problem that I see with that is shutting out he ambient noise of the shower running and all that water hitting the walls and floor, and getting a wet head.

Water hammer is a banging noise when you turn the faucett OFF. I don't think that's your problem.

Well it's also called surge flow. But does surge flow indicate the noise often associated with the water hammer effect?

You don't think there would be a hammer effect in combination with a surge flow effect? You see many cases the noise from the surge flow is loud that the hammer effect is covered up. Click the picture I posted a few responses back, they are one in the same.

Once this faucet is shut off the noise stops, right? So surge flow, water hammer --- what ever you want to call it the cause is always the same:

Design of the plumbing supply system.

@Austin Air companie

Thanks for your input. What's the best way to figure out if the noise is because of the water hammer? It doesn't happen in other bathrooms. Also, the noise is worse when water flows thru the down spout compared to water flowing thru the shower head. Could it be because if the valve?

I am not a plumber, but I have repiped two homes (I own) myself in copper, using sweat fittings. I am not licensed to do plumbing work for others. So the experience I have is mostly from a maintenance background and work I have done for myself in previous homes I have owned.

I would need to know far greater detail of your plumbing system to have any real chance of answering your question.

I suspect that “water hammer” is not a precise term. Has the International Council on Plumbing Noise Description” approved and defined it? Wait, there is not one of those? I guess we need one.

In describing the natural world, there is a similar problem, but we have such councils working with well-established rules. (Rest in honored peace Carolus Linnaeus.) I will never say that Dipterists never argue about anything, but when anyone says or writes Plecia nearctica, we have a relatively precise idea of what we are considering. On the other hand, Lovebug might mean different things to different people and is not precise. “Spanish Oak” is probably a better example of a relatively useless descriptor.

Personal experience indiecates that water hammer is a discrete noise that results from stopping the flow of water in pipes. Furthermore, it sounds very much like a mallet., or nonmetallic hammer (Do any of you know the difference between a mallet and a hammer? How about a beetle, not the kind that Coleopterists discuss,) , hitting the pipe from which the sound eminates. Similar sounds may arise from other plumbing causes and the term may be used for different noises.. This is not a big deal most of the time, but it makes communication a little more tortured. We have to ask the homeowner when and how the noise happens and what it sounds like rather than relying on one or two word terms.

Some of us need to secure federal funding to start up such a council. We can arrange to meet annually in picturesque places with moderate tempearatures to work out all the important descriptions. I project that it will take at least two years of meetings by the steering council to decide where the main meetings should be scheduled.

Yeah I completely made it up. Water hammer? how obscene. LOL.

"Blessed are those that have not seen, but BELIEVE anyway."