Attaching rigid foam to concrete
CleanCut
| Posted in Energy, Heating & Insulation on
Got a question…
What’s the best way to attach rigid foam sheet insulation to concrete? I’d like to insulate and sheetrock my basement walls. I read where Fernando Ruiz from Omaha uses Z furring and 2’x8′ sheets of rigid foam, but I was afraid the cold would migrate through that galvanized metal and cause condensation on the backside of the warm drywall. The sheetrockers I talked to today said they hate attaching to anything but wood.
Suggestions?
CC
Replies
to your question: what kind of rigid insulation are you using? How much of an R factor do you need in your area? R14, R20?
Dow makes Styrofoam SM, TypeII EPS also works well. We usually glue with appropriate adhesive.
My choice? Frame the walls, install mechanicals and sprayfoam insulate all the cavities.
Just a thought...
Use a gun adhesive foam, like EnerBond SF... set a 4x8 sheet of foam board on the ground, glue the top, then set a 4x8 sheet of OSB on top of it. Drill through and use a tapcon through the OSB/foam to secure it to the concrete (hint: the same foam adhesive will work on the concrete). Use a different foam to seal the seams between the foam/OSB panels. Screw the drywall to the OSB.
Rebuilding my home in Cypress, CA
Also a CRX fanatic!
I use 2x8 sheets of Owens Corning Insulpink (see photo):
On our Insulpink projects, the firring strips we used were 1x3's ripped out of 3/4" BC plywood. The firring strips were glued and screwed (with PL300 and tapcons). We apply the PL300 generously to the masonry in dabs, put a 2" rip of 3/4" XPS pressed into a bead of PL300 on floor at the base of the wall (this allows for a full 1x3 and an air gap below the firring at the floor--keeps wood and drywall up off the floor and provides a better nailer for base than a 1x2 at the bottom of the first course).
Then run another bead of PL300 on top of the rip and press the first full 2x8' panel into the glue on top of the rip. Keep adding full panels & 1x3's on up the wall (more about the top panel later if you want the details).
That is how we insulate a standard masonry wall. Plenty of PL300 and tapcons every 16" on the firring (I prefer the hex head tapcons--for the head I make a shallow countersink with a 1/2" spade bit).
Also we use PL300 liberally when installing drywall to the XPS and firring.
If you want to you can use 4x8 sheets in any thinkness you choose and run the firring over the top (the 2x8 product I used was 1-1/2" thick with recesses ready for the 1x3 so firring is flush).
I like the wood firring strips idea, where did you get rigid foam with insets in it?
I was planning on using EPS since there's a manufacturer 20 miles south of me. I wonder if they'd groove in a 3/4 deep recess for me to set my BC plywood in.
Thanks for the help!
Ben
I used to purchase the OC Insulpink XPS at Menards...my local store no longer carries it...check with your local Owens Corning vendors.
Dow makes a similar systems called Wallmate.I have not see it locally at any of the BB stores..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Bill,Nice to know about the Dow version.Thanks,Bass
I just glue it direct to the wall if the wall is in good shape and not horribly irregular. Then frame off of that with 1 5/8 20ga steel. I also like to put sill seal beneath the bottom plate as a sort of thermal break with the steel studs.
I'd be cautious about where you get your inspiration. I've met the guy. I've been in his houses. Like everyone, I'm entitled to my opinions. I wouldn't let him touch a doghouse for me.
Real trucks dont have sparkplugs
"I just glue it direct to the wall if the wall is in good shape and not horribly irregular. Then frame off of that with 1 5/8 20ga steel."I did a basement where the walls where cracked in the middle and pushed out. So the top was in 8" over the bottom of the foundation.The cause was fixed, the crack sealed, and the foundation had been reinforced with i-beams.I used dap of adhesvie to glue the foam to the top part of the foundation. Then I used great stuff to seal it top, bottom, and between sheets.The use 1 5/8 stud to build a plumb wall infront of it..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Thanks RW,
I'm sorry to hear that. I need to go check his homes out for myself. Omaha's not that far west of here. I've never met him, just liked his ideas about reducing cost through reduction of wasted materials and labor.
Ben
Use XPS and just glue it to the walls with PL adhesive. Like RW, I like to use 1 5/8" 20 ga steel studs in front of that. Do use sill seal under the steel channel/plate, or use Trex underneath -- no rot and no concerns about the ACQ corroding the steel.
Billy
Rigid foam to concrete...I'd shoot that stuff to the wall with a Powder Actuated Tool.
Find a Powder tool with power adjust, a #2 brown powder load should do the trick. The fastener you want is something preassembled with a large washer. Overall length of the fastener should be material thickness of the foam, plus about 3/4" into the concrete.