After returning from NZ back in March I found large patches of damp on a bedroom ceiling. As the built up felt roof above it was old I had this replaced immediately by a contractor with a good local reputation. I have an Aldi damp meter and kept the patches under regular test until the moisture content fell to under 10%. I then sealed the plaster with gloss and repainted with emulsion.
Now 6 months later I have found a small area of staining (size of an old penny) and the damp meter is reading between 12% and 43% at that point. It is in an area unaffected by the original staining, directly under a seam in the new felt, and the rest of the ceiling is giving readings of zero. My understanding is that anything above 25% is potentially serious and should be investigated. I should add that there is no water supply anywhere near the location.
The roofing contractor is treating with contempt my request for investigation under his 'guarantee', is being extremely rude about the validity of the damp meter readings, and wants a call out fee for looking at it. He says that it can take 'years' for the damp to dissipate and it could be condensation.
Any advice please?
Now 6 months later I have found a small area of staining (size of an old penny) and the damp meter is reading between 12% and 43% at that point. It is in an area unaffected by the original staining, directly under a seam in the new felt, and the rest of the ceiling is giving readings of zero. My understanding is that anything above 25% is potentially serious and should be investigated. I should add that there is no water supply anywhere near the location.
The roofing contractor is treating with contempt my request for investigation under his 'guarantee', is being extremely rude about the validity of the damp meter readings, and wants a call out fee for looking at it. He says that it can take 'years' for the damp to dissipate and it could be condensation.
Any advice please?
is the insulation in the form of slabs - I`m pondering interstitial condensation running through to the ceiling along the top of the insul. and finding a crack that is co-incidentally in line with the join in the roofing membrane above . If you can post some photos there are expert flat roofers about here that can tell the quality of a roofing job @ a glance . I`m just an old skool plumber/ general maintenance snagger 
