# Glue XPS together for extra insulation?



## NEW-B (Dec 31, 2010)

So I originally put 1/2" xps around the basement (walkout) and framed against that because I didn't want to lose the extra couple inches of floor space using 2" xps. Now I'm second guessing myself wondering if that is enough to keep the concrete warm during the cold months (Nebraska). I planned on using R-13 unfaced fiberglass in between the studs, but I wonder if water will still condense on the xps. 

What is the downside of putting an additional 2" of xps in between each stud cavity instead of the fiberglass?


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## Gary in WA (Mar 11, 2009)

Good idea.
Foam is better, far as thickness, pp. #9; http://www.eere.energy.gov/buildings/building_america/pdfs/db/35017.pdf

Minnesota heating degree days= 8253 Lincoln, Nebraska= 6278


The downside..... only possible air spaces for convective loops if any leaks are there..... I would foam seal the pieces between studs, use left-over for rim joists, and use Airtight Drywall Approach (ADA) on the drywall after pulling the batts in 1/2 to fit the 1-1/2" spaces.
http://www.buildingscience.com/docu...rs/air-barriers2014airtight-drywall-approach/

Gary


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## NEW-B (Dec 31, 2010)

GBR in WA said:


> Good idea.
> Foam is better, far as thickness, pp. #9; http://www.eere.energy.gov/buildings/building_america/pdfs/db/35017.pdf
> 
> Minnesota heating degree days= 8253 Lincoln, Nebraska= 6278
> ...


 I think thats what I'm going to do. I noticed that there was a thin clear film on the 1/2" xps that I bought. Does that need to be removed or can I just glue the other board right on top of it?


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## Gary in WA (Mar 11, 2009)

More reading for you! pp.7-10 and fig. 12; http://www.buildingscience.com/documents/reports/rr-0202-basement-insulation-systems

Gary


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