My shower pipes bang when hot water is being used. The house is 32 years old. The water starts to pulse and the banging starts. If I lessen the amount of hot water so it's lukewarm the sound subsides. Do I need a plumber?

Hi Gaylelynneg

Yes, you need a plumber (or a friend with basic plumbing skills).

It sounds like a washer is "chattering" causing issues at the valve.

Let me know the name brand of the valve and I may be able to tell you more, OK?

Mark

If it is only hot, it is most likely the faucet. If it is in hot and cold, it is possibly the main pressure regulator.

Hi - you may need a plumber, And the problem MAY be caused by trouble in the Shower's valve, as per the other answers. But the problem has a good chance of being NOT related to the valve. More likely the system is 'hammering' due to the height of your house.
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If you have a well, a well pump and pressure tank this should NOT occur. If you have water from a town supply (and no pressure tank within the house) then this problem below can happen. Hot water tank is NOT a pressure balance tank.
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Please describe the location of the laundry - suspect it is probably in the basement. Please describe the height above the basement floor of the highest plumbing (hot or cold supply) in your house - suspect at least 'second floor' - means the pipes have a 'total vertical run' in the house from 2-3' (basement location measured as height above floor) + 9-10 feet basement height and floor thickness + 9-10' first floor height & floor thickness + 4-5' on second floor. This totals 21' - 30' depending on the house. If this total altitude exceeds a critical amount (which is a function of the pressure in your system) then the WEIGHT of the water in the pipe will begin to cause a vacuum within the pipe - this can become 'harmonic' -- that is the time required to form vacuum and then fill vacuum matches the distance (just inches) the water needs to flow.
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A possible TEST of this condition is simple. Run the hot water at a trickle ELSEWHERE in the house, such as directly below or above the trouble shower. Now try the shower valve again. If the 'vacuum hammering' is the problem, it should NOT occur with a second valve slightly open (the pressure will balance through that valve). If hammering still occurs then the trouble is more likely with the shower valve.
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Despite this 'complex' explanation of cause, the solution is rather simple. This is found in most apartment buildings of more than 3-floors - just a 'stub' of pipe (one each for hot and cold) merely 6-10" long, placed VERTICALLY off a 'tee' anywhere near the top of the run. This will be a 'dead end' of pipe, which will have AIR trapped within when assembled. This air COMPRESSES as the pressure changes, and absorbs that pesky movement of the water causing the hammering.