Can I frame my basement on top of insulated walls?

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Posted by: from Brampton
11/27/2018 at 11:09:09 PM

Hello, Im in the process of getting my permit to finish my basement and would like to get a head start on the framing. My builder insulated the basement walls with R20 so I was wondering if I can framing on top of this or must I rip it down and install the insulation between the studs? Thanks

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Date/Time11/28/2018 at 1:11:47 AM

It's probably best to remove the builders insulation, then apply an interior dampproofing before carrying on.

Because the vapor barrier is supposed to be on the warm side of the insulation and assuming you wanted to keep the builders vapor barrier also it would mean your walls could not be further insulated.

Also, if the batt insulation is presently in contact with the cement wall it's probably not a good idea - best to have a small gap for breathing.

Note that when you apply for your permit your municipality will probably want to see that the entire assembly has a minimum R-20 rating. You may want to consider applying 2" of rigid insulation first to reduce thermal bridging.

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Date/Time11/28/2018 at 3:50:28 AM

Hi in Brampton you have to take it down and put it between the studs.

Basement R us Inc

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Date/Time11/28/2018 at 5:58:39 AM

You can put studs in front of the insulation, however it is not a good idea as you loose valuable space. If you press the studs tightly against the insulation you lose insulaton value, although you could gain it back if you add more insulation around the studs, but that is extra cost and not easy to do. It is best to remove the insulation and start fresh, ensuring proper water and vapour barriers are in place. You can reuse the existing insulation, but it is a pain to cut, and it is thick, so unless you are studding with 2x6 it may have to be replaced anyway. Consider spray foaming after studding, this provides superior insulaton and moisture protection, and provides maximum use of space.

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Shahid in Ajax
Date/Time11/28/2018 at 12:07:34 PM

Hello there. Framing on top of insulation will not harm and it is good that you have entire wall insulated so outside moisture will not sucked in to the wood but if you install insulation in between the studs it will give you couple of inches moor space in your finish area.

I hope you find the best advice you are looking for.



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Date/Time11/28/2018 at 1:41:50 PM

Hi James.

Based on applying for a permit for a basement build, the regulations and requirements may restrict you from keeping the original builder insulation.

To be honest, for your own piece of mind, I would remove it, that way you have a choice of upgrading the R value or even going with 2lb spray foam as one of the above suggestions was mentioned-also I highly recommend a gap between the concrete foundation wall and your breathable house wrap you can install so it allows concrete to breath- its just like skin it requires some movement of air flow to breath so doesn't gather mould, moisture etc down the road.

Hope the above helps.

Best of luck

Matt & Nick

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Date/Time2/5/2019 at 8:34:55 PM

Provided the builder included the vapor barrier and the insulation no more than 12" from the floor, you are good to frame right over top.

Hope that helps,


KLK Contracting

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