:confused: finishing basement and I am curious as to how deep should I put the insulation in the joists. I am using #15 roofing paper 3/4's of the way up the cement wall with 2x4 studs and r-12 batts, then a polyurethane vapour barrier. Now should I bring out the insulation over the 2x4 stud of the basement wall from the joist. And also the gaps behind the studs should I gently fill the gaps with insulation or leave it so it could breath. I have no moisture problem at all. If there is a gap behind the insulation and studs will not the cold air rise to the first level floor and make the floor cold. I live in south east canada.

:confused: finishing basement and i am curious as to how deep should i put the insulation in the joists. i am using #15 roofing paper 3/4's of the way up the cement wall with 2x4 studs and r-12 batts, then a polyurethane vapour barrier. now should i bring out the insulation over the the 2x4 stud of the basement wall from the joist. and also the gaps behind the studs should i gently fill the gaps with insulation or leave it so it could breath. i have no moisture problem at all. if there is a gap behind the insulation and studs will not the cold air rise to the first level floor and make the floor cold. i live in south east canada.
Actually the standard for basements has changed. Remove the roofing paper. Run vapor barrier needs to start from above grade level (but not to the ceiling) down the foundation wall, under your wall plate and up to the ceiling where you can tie into the existing vapor barrier. That said, completely fill the 2x4 void with r-12 top to bottom. See the NRC site for more info:
Keeping the Heat In (http://oee.nrcan.gc.ca/keep_heat_in/chapter_5/chapter_5_2.cfm?PrintView=N&Text=N)
or
http://www.buildingscience.com/documents/reports/rr-0202-basement-insulation-systems/attachment_download/file

Thanks TerryB,
You hit the nail on the head with the link you advised. I have gone to this website but never found that exact page, it's rite there in black and white. Thanks again