Framing a Basement Wall

10/19/2023 at 5:07:30 PM

Hi and thank you for the questions. I like to stay away 3/4" to an 1" to have a sufficient air gap, the minimal space between a stud and a wall you want to maintain is 1/2" if your trying to maximize your square footage.

All the best!!

Bart L.

10/19/2023 at 8:45:51 PM

Yes you can frame inside the builders insulation. Be sure the vapor barrier is good.

And leave a 1" space between the plastic vapor barrier and your lumber.

10/19/2023 at 8:47:24 PM

Yes you are able to frame over the builders insulation. Leave an inch between insulation and wall.

10/20/2023 at 12:52:40 AM

Frost walls should be 1/2" from the concrete foundation wall, then insulated and vapor barrier on warm side of room, you can frame again in front of that if you wish, 1/2" is min. Make sure builders original wall/insulation is done to code as mentioned and not glued direct to concrete otherwise you will have moisture issues in it and should demo & re-do the entire thing. If you are doing a false wall then you can drywall the insulated frost wall and can frame directly against the drywall, 2nd wall does not require to be insualted or vapor barrier

10/20/2023 at 5:48:24 PM

Yes, You can frame on top of builder insulation. Wood stud size 2"x4" is better.

10/21/2023 at 2:52:26 PM

You have not said what you presently have for builders insulation. In Alberta if you have a home built under the '06 Code you were only required to have RSI 1.4 (R 8) to 2' below grade and nothing below that.

Energy Codes came into effect shortly after the '06 Code was issued (effective date will vary by province) and under the new rules you're required to provide a higher value of insulation for the full height of the wall.

As this work would appear to require a building permit best thing is to consult with your local authority or someone knowledgeable about local Code requirements. If you were to frame overtop of the existing builders insulation it is always best to keep the vapor barrier on the warm side of the insulation.

Personally I don't like to see insulation in contact with a concrete wall below grade as it will attract moisture from the concrete; I also like to apply a coat of interior dampproofing (terminating at grade level).