Noisy pipes -- should I worry?

[H]

I had my bathroom refurbished about 5 years ago. All is well, except for one new thing that started last night.

When I run the hot water, the pipes apparently start to shift in the wall. This has not happened prior to last night. It is loud. It sounds like the joists are being pried apart while the water gets hotter, and a very loud drip while it is cooling down. When the water cools in the pipes, the sounds stop.

Should I worry?

Thanks.

[Doug Kanter]

Do you have a pressure regulator somewhere along the incoming pipe? Might be going bad. Call your water authority. Sometimes they'll stop by and test the pressure at no charge. It should be tested before AND after the regulator.

[H]

No pressure regulator, but this isn't a water knock. It's just creaking. Loudly.

[PipeDown]

This is a common occurance when the pipes are secured to the studs using only brackets. The expansion of the pipe causes it to slip along these fastners. A good install uses plastic isolation hangers to avoid this noise. A shame the plumber didn't spend the extra $20 or so it would have cost to use these hangers.

It is generally not a sign of impending failure. Why suddenly, perhaps one bracket was acting as an anchor and it finally gave up.

[Sacramento Dave]

Try the simple fix first. Shut off the water to the house. then open all the fixtures and hose bibs drain all the water out of the system. Refill the system and see what happens. the usually pipe air chambers into the system. in time the water absorbs the air so you have no cushion anymore.Try that might help may not cost nothing. Can you describe the dripping sound better? also when you hear the dripping see if the sound is coming from the hot water tank.

[tim1198]

Sounds like your plumber did not put air dampeners into your pipes, which are risers teed of your line so that air can absorb the vibrations and knocks.

Besides being annoying, it's probably not a huge deal. Except that if he missed putting in these risers, what else did he miss? If you can access the back of the plumbing through a closet or something convenient, you can look at it and fix it.

good luck, tim1198

[H]

Thanks to all, but to reiterate: it's not the knock that occurs when the water is turned off. It's creaking that occurs when hot water heats up the pipes.

Sounds like it's just something I'll have to accept.

[Steve Barker LT]

I'm beginning to wonder if anyone actually READS the original messages.. JEEEZE....

If you can access the pipes, and can make the holes they run through bigger that will help. If you can't make them bigger, then a lubricant appropriate for the material will help.