hidden plumbing leak

[chercat]

I have a leak that has been undiagnosed for quite awhile . I had thoguht it was a roof leak and so did the roofers - after several " fixes" , the problem still exists and now I know it is a plumbing leak , but not where it is coming from. I was told sometimes it has to get worse before you can detect it - odd advice .

Anyway , there is a water mark on my middle wall on first floor ,adjacent to the FP - above there is a bedroom with presumably no pipes . There is also a heat register , gas forced air , directly above where the leak shows on the wall - nothing on ceiling .

Today I was running hot water in my kitchen sink on first floor and could hear a dripping from above , behind the wall , I guess. Then I heard a drip onto the ceiling in the next room and finally , when I put my head to the living room with the wet mark ( never actually got wet through the panelling) , I could hear the distinct drip !

This has me very confused because I know leaks don't drip " upwards " _ I am guessing that the pressure of the hot water caused the hot water pip above somewhere to leak but I though supply leaks were constant , not intermittent ?

When I go to the cellar which is , unfortunately,. finished off I can't see anything but I can hear the drip sound , at times, pinging off the ductwork as if the drip is following a pipe or a duct.

Someone tore down a part of the ceiling for me and I can see some exposed copper ( ancient) pipes but I think these might just be extensions of the visible pipes in the kitchen above . No wetness - would there be other pipes even behind those - the wall is panelled but I can hear the drip sound which sounds like it is hitting the area in the ceiling that was torn out .

I hate to just call a plumber unless I at least have an inkling of what is going on as I am sure this will cost me a small fortune which I don't have . As a woman , I am sure I will pay more since I cannot do any repairs of this type myself and have been ripped off many times in the past.

Any advice would be much appreciated !!!

[Redwood]

We will not find your leak from here I assure you! Your dripping sound when you run the kitchen faucet sounds like a pipe warming up or cooling off and the resulting expansion. You need to see if there is any plumbing in the area where you are getting the wetness and find the leaking pipe. If there is no plumbing in that area you need to find a roofer or carpenter that can repair whatever is wrong with the shell of your house that is causing the leak.

[chercat]

Thanks - I did not actually intend for someone to find the cause of the leak - basically , what I wanted to know was did it make sense to run water on the first floor level and hear a dripping from aboce on the second floor after doing this ? To me , this makes no sense .

I have ruled out the roof as being the issue .

[jadnashua]

PVC and ABS plastic pipes expand and contract a lot with temperature changes. If this only happens when running hot water, it is your likely cause. Depending on how the pipe is supported, it could easily be trying to push upwards as it expanded - just depends on how the layout is and where it is clamped. As the pipe expands, it overcomes the friction of the clamp and jumps a little. It does this as it expands, then again as it cools off after you stop running hot water. This often sounds like clicking, popping, or dripping, depending on the way the pipes are being restricted.

A valve could leak when the stem seal isn't good. this would only happen when the valve was opened, not static, with no flow.

[Verdeboy]

You are correct when you say that it should be leaking all the time if the leak is coming from the hot water supply line. Usually when you hear a sound in the walls, it is from thermal expansion of the pipes, as has been mentioned. When there is evidence of actual water leaking when you turn on a faucet, it usually means a drain is leaking.

Have you ever heard the sound of water dripping when no water has been turned on? Next time you hear the sound, try turning off the water at your hot water tank. If you still hear it, turn off your main water at the meter. This will help you to begin to diagnose the problem.