I'm looking for some advice about flat roof.
I had it redone 3 years ago and up to Dec had been fine. In december during the very heavy rains water was streaming through the light fitting filling several buckets very dark/black water. A couple of weeks later during the heavy snowfall it once again leaked but this time round the edges of the ceiling quite a bit.
Since then nothing despite some heavy rain no further leaks or water seen. Despite no head for heights I decided to see what the problem was myself. When I got up there the bitumen sheeting appeared to be fine I could see no tears or lifting and actually looked a neat job. What did puzzle me was that in the centre there was some kind of access hole. It is circular and shaped like a small volcano with the sides about 30mm high. In the middle is a 50mm hole which I could just get my hand in. I have no idea what its purpose is and whether this is the cause of my problems.