Home Page link

Insulating Basement Walls

Home| Search | About
Login Password
Register Now! Lost Password?

Home Repair - - If it ain't broken, don't fix it. Otherwise look here. 

Page 1 of 2       1 2 > last >> Bookmark this page:  YahooMyWeb Yahoo!  Google Google  Windows Live Favorites Windows Live  del.icio.us del.icio.us  digg digg  Add to Netscape Netscape
Subject Author Date
Insulating Basement Walls lwatson 11-30-2006
If you were  Registered and logged in, you could reply and use other advanced thread options
Posted by on November 30, 2006, 7:56 pm


Here's another challenge I'm facing with my basement walls I'm hoping
to get help with.

One of the stud walls in my basement (2x4 construction) has been placed
offset from the cement wall so the face is about 4.5"-5" from the wall
(to accomodate a vent pipe for the kitchen). I assume I should use
3.5" insulation intended for 2x4 construction rather than thicker
insulation intended for 2x6 construction. My thinking is using the
thicker insulation will cause it to be compressed and lose it's
insulating qualities.

This means the wall is about 1-1.5" bigger than the 3.5" thick
insulation. Should the insulation be placed up against the cement wall
leaving an air gap between the insulation and vapour barrier, or should
the insulation be placed flush with the 2x4's leaving a gap between the
cement wall and the insulation?

Much appreciation for the insights and suggestions.


Posted by buffalobill on November 30, 2006, 8:23 pm


lots of reasearch already done for you at:
http://www.buildingscience.com/resources/foundations/default.htm
then see mfg website to localize this to you:
http://www.owenscorning.com/

lwatson@glomar-group.com wrote:
> Here's another challenge I'm facing with my basement walls I'm hoping
> to get help with.
>
> One of the stud walls in my basement (2x4 construction) has been placed
> offset from the cement wall so the face is about 4.5"-5" from the wall
> (to accomodate a vent pipe for the kitchen). I assume I should use
> 3.5" insulation intended for 2x4 construction rather than thicker
> insulation intended for 2x6 construction. My thinking is using the
> thicker insulation will cause it to be compressed and lose it's
> insulating qualities.
>
> This means the wall is about 1-1.5" bigger than the 3.5" thick
> insulation. Should the insulation be placed up against the cement wall
> leaving an air gap between the insulation and vapour barrier, or should
> the insulation be placed flush with the 2x4's leaving a gap between the
> cement wall and the insulation?
>
> Much appreciation for the insights and suggestions.


Posted by dpb on December 1, 2006, 1:40 pm



buffalobill wrote:
> lots of reasearch already done for you at:
> http://www.buildingscience.com/resources/foundations/default.htm
...

Which near as I can tell, gives no advised solutions for insulating
basement walls on the interior side, not very helpful for existing
construction.

Worth reading, though, as in humid areas particularly, vapor barriers
on basement walls can do very bad things. Not thinking about having
not had a previous basement that was finished did the vapor barrier on
the wall in TN and on the fully underground wall it did end up w/ very
bad moisture problems and failures in a very short time...

I don't really know what would be best solution overall, but agree w/
someone else that the air space behind is probably a better idea than
mashing the 6" into the cavity.


Posted by shebaaa on December 2, 2006, 5:01 am


Read through it and have similar situation. My answer that seems to fit
the bill is to use spray foam (they recommended rigid). Tigerfoam.com
sells it for DIY.

dpb wrote:
> buffalobill wrote:
>> lots of reasearch already done for you at:
>> http://www.buildingscience.com/resources/foundations/default.htm
> ...
>
> Which near as I can tell, gives no advised solutions for insulating
> basement walls on the interior side, not very helpful for existing
> construction.
>
> Worth reading, though, as in humid areas particularly, vapor barriers
> on basement walls can do very bad things. Not thinking about having
> not had a previous basement that was finished did the vapor barrier on
> the wall in TN and on the fully underground wall it did end up w/ very
> bad moisture problems and failures in a very short time...
>
> I don't really know what would be best solution overall, but agree w/
> someone else that the air space behind is probably a better idea than
> mashing the 6" into the cavity.
>

Posted by on December 4, 2006, 1:13 pm



buffalobill wrote:
> lots of reasearch already done for you at:
> http://www.buildingscience.com/resources/foundations/default.htm
> then see mfg website to localize this to you:
> http://www.owenscorning.com/
>

Thanks for all the feedback. The info on buildingscience.com
basically said if the insulation will wick moisture then place it away
from the wall. If the insulation will resist moisture then place it
against the wall.

I am using Roxul Flexibatt insulation
(http://www.roxul.com/sw47757.asp) which is moisture resistant (made of
basalt and slag) . The installation tips even say to place it flush
against the wall.

This is great stuff to work with - easy to cut, easy to handle and
install, little to no itching ... and R14 for 2x4 walls.


Page 1 of 2       1 2 > last >>
Similar ThreadsPosted
insulating basement walls June 17, 2006, 11:11 pm
Insulating garage walls January 16, 2007, 12:02 am
Insulating/Sealing Walls From Exterior October 24, 2005, 12:37 am
Question re. insulating existing exterior walls January 18, 2006, 6:08 pm
Insulating basement floor July 28, 2005, 12:51 am
Insulating Basement Wall with Gap June 7, 2006, 6:49 am
insulating basement ceiling February 21, 2007, 5:31 am
insulating basement condo May 8, 2008, 9:37 am
Insulating concrete basement floor June 26, 2006, 1:35 am
Insulating floor over unfinished basement. December 25, 2006, 6:56 pm

Contact Us | Privacy Policy

XML SitemapXML Sitemap