I've been making a 100mm hole in an external wall for an extractor fan. I drilled out the tiles and cut a hole in the plasterboard. Behind this was a cavity (approx 120mm) filled with insulation, then some layers of a sticky tarpaulin type material stuck to (approx 12mm) of timber, and then sky...I was expecting a layer or 2 of brick at some point.
Is this normal or should I be worried?
Is this normal or should I be worried?
