Hi guys,
I just finished studding a wall in a basement against the concrete foundation. The area only permitted me 3-4 inches from subfloor to wall so I had to stud 2×4’s sideways. Anyhow with such a small space I used R14 fiberglass insulation. As you can see in the pics the insulation is somewaht bulging at the seams. There’s no space behind the insulation as it is currently in contact with the cement.
http://mydrive.roadfly.com/blog/uploads/guizai_1_(Medium).JPG
http://mydrive.roadfly.com/blog/uploads/guizai_2_(Medium).JPG
http://mydrive.roadfly.com/blog/uploads/guizai_3_(Medium).JPG
http://mydrive.roadfly.com/blog/uploads/guizai_4_(Medium).JPG
My question is, is this too much insulation for the space? Will this affect my drywalling the area? I can compress the insulation so that it’s behind the studs without much effort. I understand that by compressing the insulation I’m reducing the R factor but I’m willing to forego that if this will work. I appreciate your help and advice.
Replies
You'll probably have a host of other posts on why not to do it that way, though they'll be less related with compression of the insulation and more to issue with dampness, why to not use plastic sheeting, etc..
Depends on your climate and the expert opinions still vary on the preferred way to insulate basement walls if any.
I'll let the experts chime in regarding those issues, but why can't you lose a few inches in the room to do this right? Better to stud out the wall perpendicular and keep the studs 1-2" away from the perimeter walls to allow for airflow between the insulation and the cement/block walls.
Most folks reccomend no plastic vapor barrier.
The one time I did a wall with studs on flat - it was adjacent to the stairway and only about 6-10 feet long, but it tapered up the stairway - I use the 1 1/2" rigid pink foam inbetween the studs on that wall.
JT
"Better to stud out the wall perpendicular and keep the studs 1-2" away from the perimeter walls to allow for airflow between the insulation and the cement/block walls."Why would you want air to circulate between the foundation and insulation.That allows warm moist inside air to work behind the insulation and contact the relatvely cool foundation wall and condense.But like you I did not see any reason for such a narrow wall.Where a narrow wall is desired there is foam insulation with groves for furring strips that is fairly thin. IIRC Wallmate is one trade name.
this might be of use
"Sometimes when I consider what tremendous consequences come from little things, I am tempted to think -- there are no little things" - Bruce Barton
As for the insulation question itself, you will lose some R-value compressing the FG, but the R per inch will go up with the density. There is a point when the R per inch declines again, but I promise you won't arrive there squishing it behind drywall.
The moisture issues are many and depend on your specific situation, so I will refrain from further comment.
Bill
The best solution for this problem (IMHO) would be to tear out the plastic and insulation. The efflorescence on the back wall suggests moisture to me, and fiberglass and vapor barriers in basements are big no-no. Where is the moisture going to go?... It is going to saturate the glass and the studs. This is the right time to correct the mistake.
http://www.buildingscience.com/
http://mydrive.roadfly.com/blog/uploads/guizai_4_(Medium).JPG
Are those studs nailed to the foundation? Am looking about eye level, looks like 2 nails per stud.
Are you not using a sill plate?
Re; the VB, most moisture in the area will be coming out of the concrete wall and will be trapped behind the plastic. IOW, the studs and insul will be swimming.
The foundation is a half wall where the top half is wood. I nailed a 2x4 block behind the studding into the wood to give the studs some more rigidity.
The concrete foundation behind it showed signs of moisture but it looked like it happened a long time ago, ie white calcium stains were all I could see.
But the concensus is vapour barrier in basement = bad. I'll remove it. Does the insulation need to go as well?
The studs all have about 1 inch of breathing room behind it. They are not directly touching the concrete.
So should I have used foam sheets rather than fiberglass? Thanks RW for the PDF, I'min the midst of reading it.
Edited 4/10/2006 12:21 pm ET by guizai