could anyone help or advise here on problem and solution. garage roof was done in built up torch on felt when new then staining appeared on deck (garage ceiling) so we laid out a roll off underslate felt then sheeted with metal roof sheets and trims. all done to manufacturers spec but everytime it is dampor wet the same old wet area appearsin garage ceiling, no place else but there though. pulling my hair out trying to get to bottom. can the timber draw dampness as am 100 per cent its not leaking as no drip has ever occured just this wet patch and nothing else. thanks for your time and views greatly appreciated.