insulation, vapor barriers & ventilation
Anyone have an opinion on use & placement of insulation, vapor barriers & ventilation in a brownstone roof (and secondarily walls)? We are using batt insulation in the roof and want to pitch the top flr ceiling in line with the slope of the roof. From what I have read, we need to ensure that…
Anyone have an opinion on use & placement of insulation, vapor barriers & ventilation in a brownstone roof (and secondarily walls)? We are using batt insulation in the roof and want to pitch the top flr ceiling in line with the slope of the roof. From what I have read, we need to ensure that the vapor barrier sits between the living space & the roof space. Is it ok to not use a vapor barrier (and instead use greenboard in place of sheetrock for the roof ceiling etc)? Should the insulation be separated from the joists or should we push the insulation batts into the joist spaces? What roof ventilation is required (vents and/or fans and where)? Has anyone had problems with condensation in their roof space?
Thanks!
Put the insulation between the joists, and if more will fit, put it on top as well. A vapor barrier should only go on the “warm side” (in this case underside) of the insulation. It’s fine to rely on ceiling paint to reduce vapor migration. Always ensure that there is room for continuous air circulation between the insul and the roof sheathing above. There should be an exhaust outlet already there to provide this circulation and reduce heat buildup under the roof sheathing.