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Community and Q&A

To insulate apron or not

Jb00951 | Posted in General Questions on

I have a heated garage ( with wood and propane heat) with a slab on grade. I have insulated the perimeter of the garage with 4 inches of foam 2ft in width to prevent the frost from getting under the slab.  I want to pour an 8ft apron out the front of the garage, my questions are as follows
1) should I insulate the apron? If so how should it be done? 
2) Should I be pinning to the existing slab? And does insulating make a difference if  pinning together or not
3) Should there be a thermal break beteeen the new apron and the old slab? Ie 2″ foam against the old garage with the concrete poured up against it? 
We just don’t want the new apron to crack or shift too badly.  We do have cold winters here. Climate zone 7a

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  1. Jason S. | | #1

    Plan for really good drainage slopes on top and underneath of the apron if you're not running footings below frost depth. That and really good compaction in a healthy layer of clean rock base.

    There's not a feasible way to install foam around or under the apron in a manner that would keep it above freezing. Protect the existing foundation/slab edge foam and create a thermal break that aligns with your garage door seal. I've seen at least one other thread on this site discussing approaches for that.

    I'm conflicted on the dowel pinning idea. I've heard of successes and cracked slab failures. I think good compaction and drainage are more important, but perhaps it can keep things more 'true' once you have those covered.


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