Maureen writes from Blackfalds, Alberta: "Our house was built in 1930. Originally it had wood chips in the attic, but those were replaced by rock wool batts layed between the joists. There is pink insulation in the ceiling of a couple of recently renovated rooms, but there is no continuous vapour barrier except for those rooms. The remainder of the house still has rock wool and no vapour barrier.

The joists are 2x6 in the ceiling. Above that, there is an uninsulated attic with 2x6 rafters. We would like to remove the rock wool and upgrade to pink, but with a 2x6 ceiling we can't get much R factor into the ceiling without strapping it. That is not an option because there is a finished floor in the attic. Can we put insulation into the roof as well as the ceiling, if we only put vapour barrier in one of those places? Would there be any advantage to that?"

Answer: If I am reading your message correctly, you have access to the attic for storage, and down below you have the living space where only a few rooms have been upgraded with newer insulation and a vapor retarder between the ceiling joists.

There are no easy options for you, unless you are ready to sacrifice the installed floor in the attic or renovate from below. If that is an option for you, you can redo the insulation and vapor retarder for the other ceilings of the rest of the house. However, being an older home, even if you know there is no vapor retarder such as a polyethylene sheet, the fact that you have several layers of paint - some of them are probably oil based and will act as an air/vapor retarder.

Insulation is important, but it is not the only part of a good attic and roof system. Control of moisture is critical. Ventilation is one thing; however, during periods of cold weather, the outside air cannot hold much moisture, which means that the ventilation does not carry away the moisture entering the attic from the heated portion of the house.

If you use the attic space for storage, make sure that you allow for air circulation and avoid using cardboard boxes or any other moisture absorbent materials.

Finally, the best way to reduce condensation is to eliminate air leakage: use air and vapor seals around plumbing stacks; and weatherstrip the attic access hatch.