Our house was built circa 1900. We are remodeling our bedroom which is enclosed by three exterior wood/slat lathe and plaster walls and is very cold in winter/hot in summer. About one month ago I cut and temporarily fitted 2inch extruded polystyrene R10 board over the three walls from floor to ceiling. Today, I went to remove them in order to permanently glue them in place and found that the walls were sweating or damp/wet. What should I do? I was planning on glueing the insulation in place with some metal fasteners and glueing 1/2inch drywall over top. Can I do this?
Answer:
That can mean a number of things. It could be that you already have insulation in those walls, it could mean that the walls were painted with enough coats of non-water-based paints to have become a vapour barrier on the unheated side of the R-10 panels, it could also mean that there is an air gap between insulation inside the wall cavities and the lath and plaster, etc. I would probably remove the R-10 panels and deal with the wall cavities by having the plaster and lath professionally removed, add insulation, vapour barrier and drywall.
