We had GRP flat roof done by the builder 5 years ago on our brand new extension (40 m2), work was done upto to the standard as we figure it out lately. I have leaks on three areas, unable to locate the rootcuase. I could see some blisters on few areas , water pooling on few areas, most of the places are uneven. Also could see that roof is slighly bowing towards the roof light (We have four roof lights, each one is 1mx2m). I have spoken with few roof trademen, here are the options given a) Liquid rubber on top of the existing roof with lead flashing around roof lights & edges to the wall b) repairing the area where the leak is (not sure how someone can find the rootcuase of the leak as leak might be somewhere else than the place where it leaks) c) putting new OSB nail it it existing roof and GRP finish. I am not sure which one would be the best option. your tips and advice is greatly appreciated. Thanks