Heated slab, how to insulate at garage door?

jvitez · Jan 8, 2013

I searched but couldn't find this specific answer, so point me to the right thread if it exists please.

I understand insulating under a concrete slab used for in-floor radiant heat, and the need for insulating the perimeter edge of the slab. But how do you insulate the vertical edge where the slab is exposed to the outside ground in front of the garage door? Or do you?

Blk88GT · Jan 8, 2013

I used 2" XPS and just cut it down a little so you don't see the edge through the gravel.

Highbeam · Jan 8, 2013

The same way you did on the rest of the slab. 2" foam, I used XPS with the top cut at a 45 degree angle to minimize exposure. There will be some of the top of the slab that is outside the door that will lose heat. Bummer. Should keep your door seal from freezing to the slab though.

jvitez · Jan 8, 2013

So you just backfill gravel up against the XPS, and I'm assuming a little on the top edge? With only a small amount of gravel over the top edge, won't driving over it eventually destroy the foam?

Highbeam · Jan 8, 2013

I left the form board in place so I drive over the 1.5" width of a PT 2x10 which protects the thinner concrete edge above the foam. You can't see foam, the top of the foam is cut at a 45 degree angle so that the concrete flows over it during the pour, you could also just leave it low and suffer some heat loss. If the 2x10 rots away I will just remove it and backfill with gravel against the foam or pour an apron that will protect the foam a little better.

Burl · Jan 9, 2013

Trim the foam down about 1/2" and cover it with Sikaflex, it will seal the top of the foam in case there is a spill of something that will eat the foam.

ketas47 · Jan 9, 2013

I didnt insulate the edge that meets up to my driveway. I am losing some heat but the door will not ever freeze to concrete and the 1st foot of the driveway is always clear of ice and snow.
2 other people I know did it the same way I did it and we are all very happy with the way the driveway stays dry.
I live in central Wi.

jvitez · Jan 10, 2013

Hey ketas47, I like your idea: do nothing and get a better outcome!

I do hate it when it's warmer and sunny and snow melts then freezes the bottom weatherstripping to the garage floor. I've had to pound on the door and stuff the edge of a shovel under the weatherstripping to break up the ice to release the door. It's actually amazing that the electric garage door opener doesn't even have enough power to break up the ice when it's frozen like that.

Thanks guys for the other ideas too. I want to figure out how I want to do things before I start my detached garage build.

CNGsaves · Jan 10, 2013

Any pics for this discussion . . . . this is educational for me!!

rsa · Jan 10, 2013

Try this bing search garage door chandler site:greenbuildingadvisor.com for ideas and discussion. I find it interesting to read the articles and comments, but here's a sample from one of the hits

Energy-Edge is perfect for this and we recently used it under the doors on an ICF house and under the 40'x10' R-16 insulated door for a hangar for construction of experimental aircraft which also had radiant floor heat. it's a rectangular vinyl extrusion filled with foam about 8" tall and 2 1/2" wide that makes a thermal break at this location. In an ICF house it gives you something solid to seal the underside of the door sill to. In a garage it gives you that thermal break you need under the garage door.

http://www.greenbuildingadvisor.com/blogs/dept/green-building-blog/energ...

More on Energy Edge.

ConCretin · Jan 10, 2013

I wish I had a photo but hopefully I can describe it adequately. I ran 2" rigid all the way around the perimeter of the slab and carried it right across the door openings. I'm going to pour a concrete apron on the outside that extends over the top of the foundation wall and against the exterior face of the insulation. I'll cover the exposed top of the insulation with a rubber sill strip, which will align nicely with my overhead doors.

jvitez · Jan 10, 2013

Great tips rsa and LLWillysfan. Many thanks! That Energy-Edge looks waaaay cool. Very inventive.

LLWillysfan: your description is crystal clear. Thank you very much. But aren't you concerned the insulation will be degraded by being driven over? The rubber sill strip should absorb some shock and prevent UV degradation though. Do you have a link or pic of the rubber sill strip you'll be using?

BTW, my plan is for a contractor built pole barn. Then as I have time I'll prepare the gravel floor for in-floor heat and have a slab placed. I wasn't planning on a concrete apron, only gravel abutting the slab, but a short apron is doable.

ejk52d · Jan 10, 2013

2 xps or high density eps cut on 45* to 1" wide at the top and sealed with a pourable sealant....http://www.wrmeadows.com/deck-o-seal-150-two-part-pourable-joint-sealant/ this is directly under the garage door ..I will try and get a pic.

ConCretin · Jan 10, 2013

jvitez said:
LWillysfan: your description is crystal clear. Thank you very much. But aren't you concerned the insulation will be degraded by being driven over? The rubber sill strip should absorb some shock and prevent UV degradation though. Do you have a link or pic of the rubber sill strip you'll be using?

jvitez, The top of the insulation is flush with the concrete slabs on both sides and is protected on top by the rubber sill seal but even if its compressed a bit by wheel traffic, it should still be effective. Here's a link to the tsunami seal.

http://www.auto-care.com/doorseal.html

Dick in Wisconsin · Feb 7, 2013

ketas47 said:
I didnt insulate the edge that meets up to my driveway. I am losing some heat but the door will not ever freeze to concrete and the 1st foot of the driveway is always clear of ice and snow.
2 other people I know did it the same way I did it and we are all very happy with the way the driveway stays dry.
I live in central Wi.

I was wondering how to handle this. Maybe I don't need to insulate between the garage floor and the driveway either!

Heated slab, how to insulate at garage door?

jvitez

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Blk88GT

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Highbeam

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jvitez

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Highbeam

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Burl

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ketas47

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jvitez

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CNGsaves

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rsa

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ejk52d

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