I have a small amount of water coming through the inside of my bathroom window. The render outside had blown so this was replaced however the leak did not stop. Used a hose pipe to see if we could detect where the water was coming in by but this did not work. Then I went up the attic and found that where two beams meet at the edge of the house above my bathroom window a patch of mould had appeared. Called in a roofer and they seem to think that my air vent on the roof above the bathroom as slipped and the rain is getting in that way. But the air vent in the roof is about a foot higher up on the roof than where the mould is appearing on the beam inside. The air vents were put in 5 years ago and this is the first issue with the roof we have had. So is this the right answer? Also the roofer said he will not be treating the mould because if the leaked is stopped the mould will go away. Is this the case? From the inside it doesn't look like the insulation is wet and there are no marks coming through on my bathroom ceiling. But can water get through a slipped vent and travel down about a foot before mould is created. Unfortunately you can see the mould from the small bathroom attic door but unable to walk over to that area to fully investigate it from inside.
Any advice would be appreciated.