Hi all,
I have to frame and insulate a wall in the basement that is partially below grade.
The wall will be dryloked first. The problem is that I don’t have a choice, the materials were already purchased. 2×4 studding, and fiberglass insulation. So my question is should I frame the wall as tight to the concrete block as possible or should I leave a gap between the framing and the block? If I leave a gap, I am thinking an inch and a half.
Any opinnions and advice would be appreciated.
Webby
Replies
Leave a gap behind the wall and make the HO sign something so that when the basement floods you wont be held liable for installing sponges in his walls (batt insulation).
I would urge the HO to return the batts and go with rigid.
Here's a good story to pass along to your HO:
Last year I framed a basement (we roughed ho finished). I installed rigid ins and left a gap between framing & ins. HO came in after me and installed bead board wainscoting.
Fast forward two mos, HO goes away for the weekend and comes back to a sleeping sump pump. Yep whole new basement w/ 5" of water.
He brings in a remediation crew that tells him we couldnt have done a better job.
The rigid doesnt soak up water and the gap allowed easy drying in the walls with fans.
Hope this helps.
Does the "Tuff-R" insulation qualify as "rigid" to you?George Patterson
I just use the pink (or blue) stuff from the Big Box stores.
I dont even know if i'm familiar with "Tuff-R".
I didnt pay attention to the name.
Edited 8/7/2007 10:30 pm ET by MSA1
Tuff-R is the fancy foam panel with foil on one side. Made by Dupont. Comes in a variety of thicknesses. I ask because I used it on my downstairs renovation. It would be nice to know I did something right for a change. :-)George Patterson
The down side of the polyiso (Tuff-R) is that it will absorb water like a sponge. Otherwise, it has a slightly better R value if that helps you feel any better
So, basically, it's an open cell foam rather than a closed cell foam...
From this location http://www.dow.com/styrofoam/media/news/backgrounders/bncfacts.htm
TUFF-R™
TUFF-R is a patented high-performance polyisocyanurate foam core with radiant barrier-quality aluminum foil facers on both sides (one side reinforced).
TUFF-R reduces water and vapor intrusion from the outside. First, it warms the wall cavity, reducing the potential for dew point condensation forming in the walls. Second, it acts as a component in a secondary drainage plane, allowing wind-driven rain to move quickly down the sheathing surface and out the bottom of the wall.
With a long-term R-Value of 6.5 per inch, TUFF-R offers the highest insulation value of any foam sheathing, translating to significant energy savings.
TUFF-R consists of one three-ply facer and one pure aluminum facer, and both are a radiant barrier quality reflective foil.
Uses:
New frame wall construction behind masonry and siding
Interior retrofit of existing walls under a new interior finish of one-half inch minimum gypsum board, or equivalent, thermal barrier
Exterior retrofit of existing walls under new exterior sidings
Underlayment beneath roof shingles, over roof decks and in cathedral ceilings
Building Requirements: TUFF-R complies with ASTM C 1289 Type 1, Class 1 and meets IBC/IRC requirements for foam plastic insulation
Thanks for the advice. I woll try to change the H. O. mind
Webby
I'm thinking as long as you didnt use batts, you're good.
I'd put up a layer of 2" EPS (blue or pink board) against the block wall first, then frame the wall against that. Framing directly against the bock wall is a proven poor design.
I vote for the rigid isulation (blue or pink). It's a closed cell foam, won't absorb moisture. the tuff R is a iso cyanurate I believe. I don't know much about it other than it's a different type of foam. definitely leave an air space between the foam and the framing.
"it aint the work I mind,
It's the feeling of falling further behind."
Bozini Latini