Insulate a Cathedral Ceiling
LESLIE: Chris in New York needs some help with insulation. What can we do for you?
CHRIS: I have an attic that we’ve converted into a bedroom and it’s never been insulated properly so, as you can imagine, in the northeast it gets kind of cold up here in the winter.
CHRIS: So what I’ve been thinking about is just maybe having to gut it again; you know, remove all the sheetrock and just put up insulation. But what I wanted to know is since it’s the attic and it gets kind of hot, you know, by the roof, is there a special technique or a special insulation that I have to buy that’s, you know, different than any other part of the house that you would insulate?
TOM: That’s a good question. When you have a cathedral ceiling like that, you can’t fill the entire bay, the entire depth of the ceiling with insulation; you must leave room for ventilation. So if you have a 2×8 rafter, you can only put in insulation that’s say, about six inches deep; to leave that additional two-inch gap between the insulation and the underside of the roof sheathing so that you can have airflow, which will keep that space dry. So if you have no insulation now, then it’s worth taking the drywall down and doing this. If you already have insulation then I don’t think that’s going to buy you anything.