Alan Gibson

Alan Gibson's Posts

Q&A: How Flat Does a Subgrade Need to Be?

Q: When you're preparing the subgrade for an insulated slab foundation, how flat does the surface need to be before you lay out the rigid foam? Is "pretty flat" good enough, or do you have to eliminate every minor hollow and high spot? Read more

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Super-Insulated Slab Foundations Super-Insulated Slab Foundations

Compacted drainage stone and a thick layer of foam prevent frost damage and keep the heat inside the building. Read more

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JLC Field Guide
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