# Insulating basement in Ontario with EPS and batts



## Windows on Wash (Aug 30, 2011)

EPS is very vapor open so it will dry through that foam.

http://buildingscience.com/documents/information-sheets/basement-insulation


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## bodiroti (Nov 8, 2012)

I've read that article


> The best insulations to use are foam based and should allow the foundation wall assembly to dry inwards.... No interior vapor barriers should be installed in order to permit inward drying.


So it will be able to dry outwards and mold shouldn't be a problem, even though optimally I would be able to build so my walls could dry inwards?


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## Gary in WA (Mar 11, 2009)

With different grades/densities of EPS up there- Type 1, 2, or 3; http://www.nrc-cnrc.gc.ca/ctu-sc/ctu_sc_n36

http://www.nrc-cnrc.gc.ca/ctu-sc/ctu_sc_n70

And, surely the Inspector read this; http://www.cmhc.ca/odpub/pdf/66564.pdf 

Gary


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## 123pugsy (Oct 6, 2012)

In the same boat here. Inspector says vapour barrier so I will spray foam all my basement walls, no vapour barrier and probably cheaper than Styrofoam and Roxul combination.

I believe I am getting the foam cheaper than buying the materials. I know my two upstairs floors of insulation will be cheaper installed than what I can buy the materials for.

Get yourself a quote, you may be surprised.


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## Gary in WA (Mar 11, 2009)

Your new (06-24-15) energy guide on* page 6.2.4 *allows rigid foam board with ADA drywall or use of a Smart Vapor Barrier (Nylon-6) rather than a poly sheeting for dry basement concrete walls. http://www.nrcan.gc.ca/energy/effic...ng-the-heat-in/basement-insulation/15639#a6-2

Has your Inspector seen this or is there a local amendment to the Code...

Gary


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## bodiroti (Nov 8, 2012)

Sorry, I missed your response. I haven't started the work yet. My building permit was refused because I didn't include the poly vapour barrier on the warm side of the assembly. I'm getting ready to resubmit the permit now and will go through the documents you found and ask the Plans Examiner what's allowed. Thanks for the help!


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## 123pugsy (Oct 6, 2012)

bodiroti said:


> Sorry, I missed your response. I haven't started the work yet. My building permit was refused because I didn't include the poly vapour barrier on the warm side of the assembly. I'm getting ready to resubmit the permit now and will go through the documents you found and ask the Plans Examiner what's allowed. Thanks for the help!


As I said before, spray foam will cost the same as your materials alone and no VB required. I priced it already.

I'm in Ontario also BTW.


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## bodiroti (Nov 8, 2012)

Thanks, I will get a quote on spray foam once everything's opened up--the basement is already finished, but with wood paneling and framing that's probably not up to code, so once I demo that I'll have some spray foam guys in. Either way, I want to let the city permit people know their way of making me do things is wrong and try to get permission to do it the correct way.


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## bodiroti (Nov 8, 2012)

What R-value are you getting with the spray foam? I think XPS/EPS + Roxul R14 batts is > R-value than spray foam.


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## 123pugsy (Oct 6, 2012)

bodiroti said:


> what r-value are you getting with the spray foam? I think xps/eps + roxul r14 batts is > r-value than spray foam.


3" = r 20.


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## Dusty53 (Jun 28, 2021)

I believe the problem is that you used EPS and should of used XPS if you wanted a vapor barrier.


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## Nealtw (Jun 22, 2017)

Dusty53 said:


> I believe the problem is that you used EPS and should of used XPS if you wanted a vapor barrier.


This thread is old and we tend to let them slide into history .  Nov 13, 2015 
Welcome to the site.


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