# Yes another basement insulation question...confused



## jdtox (Jan 9, 2012)

I've read through a ton of basement insulation threads on here and all it has done has left me extremely confused.

I live in michigan. It gets cold here in the winter and humid in the summer. I have just finished 2x4 studded walls around exterior. I do not have moisture issues. I have built all the walls away from poured foundation walls at least 2" except for one. Unfortunately it is only about .5" away. Was first wall I did before reading and it is already secured and don't want to move it now.

Anyhow I am confused...

I have several people who have told me not to insulate at all, just put up the drywall.

I have been told to just use kraft faced insulation with kraft barrier facing interior side.

I have read about using unfaced batts with plastic barrier over top.

I have seen insulation at Lowes completely wrapped in plastic.

I have read about Roxul possibly being a better choice. Plastic barrier or no with this stuff?


I don't know if there is a correct way, but at this point I just want to pick one and get it done. I chose not to go with XPS against the walls, maybe a mistake but too late to do anything now with all walls secured and in place.

So is it unfaced with plastic? Kraft faced? Plastic wrapped? or Roxul? Roxul w/plastic barrier?

Help!!!!


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## christoff (Feb 26, 2008)

since you chose to not go with the 2 " xps which does not require a vapour barrier, you can use roxul or pink insulation that has the correct r value for your basement in between the studs and use a vapour barrier then drywall


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## jdtox (Jan 9, 2012)

so is a plastic vapor barrier different than a kraft vapor barrier?


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## jdtox (Jan 9, 2012)

and what about the johns mansfield stuff that is basically encased in plastic?


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## Gary in WA (Mar 11, 2009)

No plastic inboard of the batts: http://www.buildingscience.com/documents/reports/rr-0202-basement-insulation-systems

The others you mentioned, can't go wrong with foam: http://www.carb-swa.com/articles/in%20the%20news/HomeEnergy_The%20Challenges%20of%20Basement%20Insulation.pdf

Find the most moisture tolerant system. You don't want a plastic vapor barrier or paper vapor retarder below grade unless the foamboard is thick enough; http://www.buildingscience.com/docu...merica-high-r-foundations-case-study-analysis

ADA the drywall, air seal the rim joists, use foam poly sill-sealer under the code required p.t. bottom plate for a thermal/air/capillary break. http://www.greenbuildingadvisor.com...ressure-treated-sill-plates-and-building-code

http://www.buildingscience.com/documents/information-sheets/air-barriers-airtight-drywall-approach/

http://www.buildingscience.com/docu...joist/files/bscinfo_408_critical_seal_rev.pdf

No air gap to the foam/insulation or behind the f.b.; http://joneakes.com/jons-fixit-database/743

Gary


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## jdtox (Jan 9, 2012)

Thanks for the reading material. Still left confused though as to whether or not to have a vapor barrier and whether or not that barrier is ok as kraft faced or should be plastic.

I live in michigan and it gets cold here in the winter.

I can tell for for certain that I absolutely regret not putting up the XPS foam BEFORE putting up my stud walls. Since I wanted to do this properly. Unfortunately I have gone too far now to turn back as all electrical and plumbing has already been done.

Is there anyway to put XPS foam in between the stud cavities?

Is ROXUL a better choice at this point due to its qualities then?


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