Pipe noise from shower body?

Hi all,

A year ago I had my bath redone. Ever since then when the shower is turned on there is a banding noise for about 15 seconds. It doesn't sound like water hammer but as if the pipes are expanding and rubbing against something. Then after the shower has been turned off, every so often for the next couple of hours I hear a similar sound but only 1 band at a time, as if the pipes are cooling and then contracting. Any ideas what this could be? The shower body is a single handle from American Standard.

Tom

First guess is that it's expansion/contraction on the drain line.

The drain is binding on a wood surface under the floor or in the wall.

Second guess is it's the hot water supply line expanding and contracting. Pour some boiling water down the drain and see if it happens. How much was "redone" when they redid the bath? Do you know what kind of pipe is in the supply lines?

Your guess sounds right. The HW pipe is expanding fast when heated by the water then slowly cools. It is rubbing on a joyce or stud and making the sound.

To correct this problem, you need to isolate where the noise is coming from. If you have a plumbing access panel behind your shower, that would be a great place to start.

No Access

Most of the piping and drain pipe was redone. The supply pipes are copper, not sure of the size. The drain pipe is PVC. I was very displeased with the wokmanship of the plumbers who did the work. In fact, they failed to attach the shower elbow to a cross brace. In stead they attached the supply pipe between the shower body control and the elbow about 3/4 of the way up with a simple clamp. So now I am afraid to make adjustments to my shower head.

Anyway, I agree that it is probably expansion and contraction but could the pipes possible cool that slowly? I ofter hear the noise even after an hour after the use of the shower. Granted I did insulate the pipes to reduce noise. Could part of the problem be due to intermittent spikes in water pressure either from the boiler or from the street?

An hour? I don't think that long. Don't believe water pressure has anything to do with it.

When pipes expand and contract, they make a ticking sound: tick, tick, tick...

This ticking usually only lasts a few seconds to a few minutes max.

If your pipes are banging, then you probably have a loose supply pipe. Sudden changes in water pressure would definitely cause a loose pipe to bang at odd times during the day and night. If you're really lucky, it could be simply due to a leaky toilet fill valve. Try turning off all your toilet shutoff valves and see if the problem goes away.

If it doesn't, you should consider cutting out a small section of wall behind the shower and creating an access panel, so you can locate and brace the loose pipe(s).