Under slab insulation
I am building a house in MN(zone 6A). I have a couple question regarding under slab insulation.
1. I am planning on using 4″ of high density EPS. The question is if it would be overkill compared to using 2″?
2. Secondly, I had bought a couple pallets of reclaimed EPS sheets. The problem is that they are of varying thicknesses ranging between 1.5″ and 2.5″ with odd thicknesses like 1.80″ and 2.3″ etc. I will be making sure to layer them in a way that I achieve close to 4″ of thickness. But my question is that what would be the acceptable tolerance for the foam height? Would it be ok to have the foam 4″ thick in some areas and 3 3/4″ in others and so on?
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