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I have a basement room that had some water issue due to a leaky bleeder valve. The leaky pipe did not damage the drywall ceiling, but it did get into space between drywall and concrete, as well as the carpet on the floor, so I pretty much yanked out all the old carpet, drywall that were concert facing, and all the old bat fiber glass insulation.

Now I have a room with a ceiling and bunch of wall framing that are all in pretty good shape. I understand that now days rigid foam board glued to the concrete wall is the new and better way of doing things.

So now I have couple of options:

  1. Do it the old school way. fiberglass batt insulation between the studs (which will be touching the concrete), vapor barrier to seal the stud and insulation, then drywall.

  2. Tear down the ceiling and old wall studs, put in the rigid foam board, re-do the studs, put in fiberglass insulation, vapor barriers, then drywall.

  3. Hire someone to put in spray foam insulation between the studs, vapor barrier, then dry wall.

Obviously, option 1 is significantly less work and cheaper.

Now, here is my dilemma, if it was a fresh unfinished basement, I would definitely go with option 2 or 3, however, I'm only re-doing one room in the basement, the bathroom and rec room in the basement were all done in the old way.

I live in Eastern Ontario, so long cold winters and pretty mild and short summers. the basement is almost completely below grade.

Just wondering what are folks recommendations on this.

Thanks.

  • Just a note on your options 2 and 3: you don't need vapor barrier with sealed rigid foam boards, or with closed cell foam insulation, as the insulation itself is air-impermeable. Adding a vapor barrier actually will cause more problems by trapping moisture in the wall cavity. – gregmac Oct 12 '16 at 14:59
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I think your best bet is spraying foam, then install studs and drywall over that, leaving the spacing of the studs free and able to breathe. Fully insulated walls or vapor barrier and similar practices is known to cause molding since the moisture will have no way to evaporate. So do not use any vapor barrier. Normally it should go underneath the foundation or on the outside wall. enter image description here

Look what insulation and vapor barriers do. enter image description here

  • Insulation and vapor barrier is okay, but it has to be installed in a way that allows drying (allowing moisture to escape). buildingscience.com has some really good information on how to do it properly. My guess from your picture is that there's active water intrusion (maybe leaking from the window), which is a problem that needs to be solved: the design of insulation systems is to allow moisture to escape, not huge amounts of water to dry. – gregmac Oct 12 '16 at 14:51
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Do option 1 with a twist: 6mil poly on concrete wall (to prevent moisture migrating inside), then regular studs +batt insulation + certainteed membrain (or other "smart" vapour barrier) vapour barrier. Membrain is a new "smart" type: it's permeance changes from <1perm to 10 when RH inside we all goes over 60%

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