Hi,
I have a 50-year-old backsplit that has a large uninsulated crawlspace under the living room and kitchen. The crawlspace has a concrete floor and is about 4' high. It connects with the heated part of the basement via a short door. It's not directly heated by a duct, but the temperature never gets anywhere near zero.
In winters (which are pretty long in Ontario), the living room and kitchen get very cold; the floor is extremely cold. My plan is to insulate between the joists in order to keep the heat where it is needed. I plan on running a duct into the crawlspace to keep pipes from freezing.
My question is ... do I need a plastic vapour barrier? I thought so, but a Government of Canada website on the topic says no. To quote:
"If the floor above the crawl space is already covered with an impermeable material (e.g., linoleum or plywood), you already have a vapour barrier where you want it. The solid materials of the floor can serve as the air barrier, but be sure to locate and seal any air leaks."
This is good news for me, because I don't know how I could lay strips of barrier in the bays between the joists and make an airtight seal. It's way easier just to stuff batts betwen the joists. But is this is a mistake? If it matters, I'm using Roxul insulation -- unfaced and not affected by moisture.
Thanks for any insights anyone may have.
Tom