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where to insulate on slab on grade reno

Jason Smith | Posted in General Questions on

I am making use of an existing slab and converting our detached garage into a dwelling unit. 

I am adding a strip footing along the perimeter and insulate on the top of the slab, with a floating floor on top of that. The plan is to turn this into a thicken edge slab, essentially. 

Is there a benefit to insulating the exterior of the footing/foundation wall, up to the top of slab. 

Would it make more sense to insulate on the inside of this wall or will it not add anything where there is already insulation on top of the slab?

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Replies

  1. Jason S. | | #1

    Your climate zone determines whether or not slab edge insulation is required and how much would be needed.

    I've never seen a foundation wall added to a floating slab after-the-fact...instead look into frost-protected shallow foundations IRC R403.3. If you need slab edge insulation anyway you may be able to forgo the added concrete with that approach.

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