dripping coming from within the pipe??

[davidbrown]

i need help, i stay in a block of flats and i am at the bottom and the sewage pipe for all the flats runs right through my flat.
recently i noticed there was a dripping coming from the area where the pipe was, stripping the area down to get to the pipe i noticed there was no leak, but there was still a dripping noise when upstairs was using the shower or flushing the toilet.
my flats maintanance guy came round and confirmed that there was no leak, he also said he couldn't hear any dripping either but what he did was put heavy insulation in to dampen the sound of the dripping.
the dripping sounds as though its hitting something possibly even metal but i dont understand why?
what i am wondering is, is it possible for dripping to be happening within the pipes?
has anyone ever came across this problem before?
is there anyway to solve this?

 

[justlead1]

Hi. It can be difficult to tell the difference between drippingwater and the stress noises caused by expansion/contraction. Packing the boxing with a sound proofing material may be the best that can be done without major work, cost and mess. Good Luck

 

[fuzzy]

may be a drip but were do you start without a noticeable leak?

 

[adrianfs1]

this is not a dripping noise, it is infact a noise related to stress relief sound, i live in a 2 up 2 down and when the wife uses the bath then empties it you can indeed hear what sounds like dripping, but really the water is running to quickly for a drip, actually the drip noise is the wooden floor relieving the stress of the wieght of the bath, and/or the stress on the soil pipe due to the weight of the water. insulation should help.

 

[dontknowitall]

Could also be the expansion (and contraction?) of the waste pipe(s) if they're jammed against a hot pipe (I have this at home - luckily I wasn't a plumber before I stuck these in!)