For those of you who have done FPSF slabs for your garages, are there any special considerations that need to be taken when putting the insulation around the front of the garage where the driveway meets? Do you still insulate up the side of the slab and still install the skirt insulation out from the bottom of the slab?
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Where frost protected shallow foundation meets driveway
- Thread starter Mike_72
- Start date
mcbane
Well-known member
I haven’t done this but have read up on the topic. You need to extend insulation away from all sides of the slab, whether that insulation will be covered by soil, asphalt, or a concrete driveway.
For the slab edge it is common to taper the insulation toward the top of slab so you don’t have a lot of foam exposed. If the driveway will be concrete you may want to end the insulation an inch or two below top of slab, form a slot, and fill the void with backer rod and sealant.
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For the slab edge it is common to taper the insulation toward the top of slab so you don’t have a lot of foam exposed. If the driveway will be concrete you may want to end the insulation an inch or two below top of slab, form a slot, and fill the void with backer rod and sealant.
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Okay so I have laid out the formular 300 in front of the garage entrance starting from the edge of the underslab insulation and it’s extending out and down at about a 15 degree angle. I tried to ensure that the 3/4 clean was as flat as possible before laying the foam. I’ve backfilled about 6-8” of 0-3/4” on top and it isn’t feeling very solid, almost spongy feeling. Should I rent a plate compactor before adding any more fill? Or should I forgo the skirt insulation in front of the garage door?
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Stuart in MN
Well-known member
Nobody has any advice on this topic?
Sometimes topics drop off the first page quickly so they get missed. Next time, just bump the topic up to the top.
Radix2
Well-known member
Okay so I have laid out the formular 300 in front of the garage entrance starting from the edge of the underslab insulation and it’s extending out and down at about a 15 degree angle. I tried to ensure that the 3/4 clean was as flat as possible before laying the foam. I’ve backfilled about 6-8” of 0-3/4” on top and it isn’t feeling very solid, almost spongy feeling. Should I rent a plate compactor before adding any more fill? Or should I forgo the skirt insulation in front of the garage door?
You definately want to rent a compactor for any fill going under your approaches, foam or no foam. Since concrete/bricks are an excellent conductor if heat, that is the last place I would leave out the foam. Hate to have the entrance heaved right under your door.
like2wheel
Well-known member
Sometimes topics drop off the first page quickly so they get missed. Next time, just bump the topic up to the top.
Isn't that what he did?
Just this weekend, I dug 24" straight down at my door thresholds & put in 4" of xps. Hadn't thought about angling it outward farther even though I did do that on the north & west sides of the building.