I have investigated the square hole in the wall beneath the spare room window; it goes through to the void between the ground floor ceiling and the first floor; you can see all the electrical wiring etc. It had a rubbery sealant around it with the impression of something round with screw-holes at the four corners; maybe a vent cover. I stuck a quails egg box in there for now, though the inside of the
hole doesn't feel wet so doesn't look like it is contributing to the render problem.
Check with Joe if the hole will still be there when he is done and get a cover if so.
I have investigated the square hole in the wall beneath the spare room window; it goes through to the void between the ground floor ceiling and the first floor; you can see all the electrical wiring etc. It had a rubbery sealant around it with the impression of something round with screw-holes at the four corners; maybe a vent cover. I stuck a quails egg box in there for now, though the inside of the hole doesn't feel wet so doesn't look like it is contributing to the render problem.
Check with Joe if the hole will still be there when he is done and get a cover if so.