Rainwater reacting with building materials
Rainwater appears to have seeped into my extension due to lack of cavity trays and is causing a chemical reaction producing an irritant gas that smells of plaster or emulsion. I know that plasterboard reacts with rainwater to produce hydrogen sulphide but that smells like rotten eggs. so what could it be? There is no sign of dampness so it must be a very small amount of water.
Advice from 2 local tradespeople
Inject the outside sink wall drill 6mm holes every 4 inches and then hover out the holes to get rid of all dust. After inject the wall with damp proof this will make it watertight completely repoint the holes and you will see the difference within a month.
I would suggest either a survey for damp or even call building control about the lack of cavity trays that were missed on inspection.
