How to secure foundation insulation?

[cdnc]

Starting my build. Quick question - I'm planning to insulate w 2" insulation on inside of foundation wall and insulate below the slab. How do I temporarily secure the insulation to the foundation before backfilling w gravel?

Cheers

 

[jrb2]

I assume you are talking about Styrofoam. I would glue it with construction adhesive...but not just any construction adhesive will do. You can get glue especially for foam.

 

[myredracer]

A few small dollops of PL400. Or anything else that is sticky like maybe foundation coating (1 gallon)? Whatever you use, you want the top of the foam pieces held tight against the foundation wall so fill material doesn't get behind the foam and push it out (BTDT).

 

[Chris705]

I doubt an adhesive would work in the cold ( did mine in the early fall and used adhesive made for foam board)...I'd have to suggest a "Tapcon" screw and fender washer along the top edge about 2 or 3' oc to hold sheets in place until backfilled...it might seem like overkill but keeping it in place while backfilling is important. Pay particular attention to the OH door area where they dump backfill right on top of the wall to be able to drive back into your pad...when dropped from above the insulation will want to pull away from the wall. Keeping it tight and secured there will allow your hauler to dump loads in side the pad and push into the foundation wall area.

Good Luck!

 

[naturalgas]

I just put a few shovel full of the gravel to hold them upright. Worked fine. Doesn't take much to hold them till the the truck dumped the rest of gravel to fill and compact the area.


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[Casey69]

i'm doing something similar. foam insulation on basement walls. got a few reviews on this loctite foamboard glue that aren't very good (http://www.homedepot.com/p/Loctite-PL300-10-fl-oz-Foamboard-VOC-Adhesive-1421941/202020476).

so i tried putting some liquid nails on the foamboard to test it out, but was able to peel the bead of liquid nails off (without much effort) the next day.

was thinking about trying another construction adhesive (plx00), but might end up using this:
http://www.amazon.com/dp/B000XJJLZS/?tag=atomicindus08-20

but you have to buy the $50 gun to get it out of the can:
http://www.amazon.com/dp/B0002YOMJE/?tag=atomicindus08-20

 

[Leaflessshadetree]

A couple strips of tape held mine. I also taped the seams.

 

[myredracer]

PL400 can be applied down to -12C and PL400 Premium is okay to -17C. Keep the tubes indoors until ready to use. Both are okay with wet surfaces. I always use the Premium version anytime I use a construction adhesive as it spreads more easily. Costs more but you don't need as much. PL400 takes 7 days to cure and the Premium 24-48 hours.

Don't know about the other brands, but PL400 (and Premium) is a very strong adhesive as long as the instructions are followed.

All the OP needs to accomplish is have the foam stay against the foundation wall until the backfill is placed and compacted so strength and cure time of the adhesive is not an issue.

I've used PL400 Premium on the foundation walls of a crawlspace to affix rigid foam and not had any issues. Just used a few dollops for it to stick.

 

[dirttracker18]

PL Premium or spray foam from a can. I have used spray foam in a pinch and it works.

 

[nick2010tundra]

This is what I used, pl and glue work terrible.

https://www.us.hilti.com/anchor-systems/insulation-anchors/r217

Hold sheet in place, drill 5/16 hole thru into concrete and then use a hammer and tap them in, I did 40 sheets, 5 per sheet ( one in the centre and one at each corner ) by myself in one day with zero issues. The foundation was all I had at the time and it lasted 3 weeks till I had a roof on and not one sheet moved.

Beats using foam cans at $7 dollars a can and the directions say one can for every sheet

My Neighbour actually used these to attach his foam and if you line them up right you can attach drywall too them also and use them to hold your drywall. I wouldn't recommend it but hey whatever worked for him

 

[4cyclic]

Same here, foam can works good.

 

[Crazy68Dart]

Liquid nails Heavy Duty and wedged tight against wall until it cured.

 

[RickP]

This stuff is a lot easier to stick to the foundation:

But it probably doesn't insulate as well. They're just dense fiberglass mats.

 

[NUTTSGT]

I have no idea if it would work holding or what it would do to the foam but I wouold try a tube of roof cement. It should close to the consistency/make up of the water proofing that is on the wall.

I'd do like Crazy mentioned, caulk, wedge and let it dry.

 

[Vt_k9]

I used the hilti nails with a wash to secure the foam until it was back filled. Then I filled the holes with the foundation coating. Due to the temperature changes here I only put the coating on one wall at this time. I will finish the other walls next spring when it warms up. When I built my house I used a concrete nail with roofing washer. They did not hold so well. Good luck, Mike

 

[gpflepsen]

I just put a few shovel full of the gravel to hold them upright. Worked fine. Doesn't take much to hold them till the the truck dumped the rest of gravel to fill and compact the area.


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Did this 8 years ago with 2" extruded foam board on wall exterior. No adhesive required. Foam under entire slab too. Makes the basement oh so comfortable in winter when frost depths are ~40 inches.

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[Casey69]

i'm going to test the liquid nails subfloor adhesive (LN902) tonight. it's rated for exterior AND foamboard use.

looked at the PL400, but it was $8/10oz tube (ouch), while the LN902 comes in both 10oz & 28(?) oz tubes.

 

[Jon_E]

I used some kind of foam adhesive from Home Depot that turned into a gel after a few minutes. It worked but not great. I still got some small stones between the wall and the foam when it was backfilled.

My contractor wanted to backfill with no adhesive - he said just hold the foam board against the wall until the backfill holds it up. I didn't trust that method.

 

[cdnc]

Many thanks gents for the recos! I ordered the PL Professional in large catridges which I will try. It looks right for the current conditions and I like the fast cure as we are backfilling the next day. Thanks for the tips!