# Advice needed to pass insulation inspection



## statix72 (Sep 11, 2015)

Hello all,

First post!

I have a few questions before I insulate my basement and call in inspection.

I have a lot of R15 insulation I purchased on a closeout at a local home center. It is for 2x4 wall construction. Some of my walls in the basement are 2x6 and some are 2x4. Can I use the 2x4 insulation in a 2x6 wall cavity? Would this not pass inspection?

Some walls are cement foundation walls, others are plywood (think walkout basement). I can't find a concrete answer (no pun intended) on whether I should or should not use insulation with a kraft barrier on the cement walls. I've heard arguments stating turn the moisture barrier in (touching the cement), do not use a moisture barrier, and also that typical installation (where the moisture barrier is facing out) all have their merits. I have read the plywood 2x4 or 2x6 areas are fine to use the moisture barrier facing out as is typical.

Any insight would be greatly appreciated and I'm in the Charlotte NC area for climate reference.

Thanks!


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## Windows on Wash (Aug 30, 2011)

Personally I wouldn't put anything fibrous against the bare concrete wall. There are ton of good insulation threads on here that talk about effective strategies for insulating basement walls. I would encourage you to read over some of those before taking on this project.


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## Gary in WA (Mar 11, 2009)

Welcome to the forum!

Your Zone 3 *doesn't require* basement insulation nor a vapor barrier- *read footnote "f"; * http://energycode.pnl.gov/EnergyCodeReqs/index.jsp?state=North Carolina 
the plywood wall requires above-grade insulation (wood frame wall) per link.

Help on other energy related questions; http://ncenergystar.org/sites/ncenergystar.org/files/NC Energy Code -- Res_and_Comm 2012.pdf

Gary


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## Windows on Wash (Aug 30, 2011)

With 3,300 HDD, I would still insulate it. 

http://www.climate-zone.com/climate/united-states/north-carolina/charlotte/

Good Building Science read on it. Quote from article: _Basement walls should be insulated with non-water sensitive insulation that prevents interior air from contacting cold basement surfaces

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

_Oak Ridge recommendations (R-5 - R-9): http://web.ornl.gov/sci/roofs+walls/insulation/fact%20sheets/basement%20Insulation%20Technology%20fact.pdf

Good Read. Granted the guy is from Maine: http://www.energyauditingblog.com/should-i-insulate-my-basement/


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## Gary in WA (Mar 11, 2009)

Lol, I left him with your statement; "Personally I wouldn't put anything fibrous against the bare concrete wall." so he would *ask you* what to use... trying to respect you with the leading answer you gave. My answer was to his title question and passing inspection. Three of those four links I have used many times on this forum, with about as much explanation before each, they are sure handy, lol. 

"I can't find a concrete answer (no pun intended) on whether I should or should not use insulation with a kraft barrier on the cement walls. I've heard arguments stating turn the moisture barrier in (touching the cement), do not use a moisture barrier, and also that typical installation (where the moisture barrier is facing out) all have their merits. I have read the plywood 2x4 or 2x6 areas are fine to use the moisture barrier facing out as is typical."------------------- use foamboard below-grade, no vapor barrier. Just ask if you need more help...

Use batts above-grade, *no vapor barrier*, use *foil-faced* polyiso at the rims, ADA the drywall;http://buildingscience.com/document...sheet-310-vapor-control-layer-recommendations

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

Gary


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