I'm trying to do a rapid makeover of a house that was up for sale and now my daughter may rent it from another family member. It's 1920s semi, solid walls, high ceilings and was re roofed 20 years ago from bare slate to felt plus concrete tiles. The eaves have vents but there's no ridge vent and the felt is entire from eaves to ridge.
The loft space is too small to be useful (house is only about 4m width) but is boarded and a 50mm thickness of fibre glass wool was laid on top of the boards. In the last winter I noticed some condensation on the fibre glass, so I rolled it back . The ceilings are strange in that they are hardboard fixed to the joists with battens and glued to the battens are 9" square fibre board tiles. So there is quite a lot of scope for warm, moist air to leave the room and condense in the roof.
I'm guessing my first step is to put a couple of vent tiles near the ridge and then lay 100mm of wool in the loft or should I make the whole roof warm by adding celotex between and to the rafters?
AJH