I have discovered a leak somewhere in the house and it appears that it might be coming from a fall pipe (from a bathroom) that is routed internally (due to an extension being built). Of course I would prefer not to start ripping off the plasterboard to find the fault and was wondering of there is anything that can be poured through the pipes to attempt a repair.
Failing that, any other thoughts on how I could attempt to fix this?
Ta.

