My daughter bought a house 18 months ago with a brand new felt flat roof, the construction of which had been made under building regs. She has suffered various stains to the bedroom ceiling underneath.
The flat roof itself appears to be reasonably well constructed and no obvious splits etc - its covered with fine stones.
However my question is this. The flat roof has three aluminium vents set in it - conical with an umbrella shaped top.
When I took the tops off, the inside of all three vents was quite wet.
Looking down onto the top of the roof ply I could see a relatively small hole, presumably to vent the cavity inbetween the ceiling and the roof ply.
Could condensation from these vents be causing the staining to the ceiling?
Are these vents the correct way of venting a flat roof?
If not what is recommended please