Quote:
Originally Posted by TobyB
Ok, be kind, I'm new at this-
where do I go, as a DIYer, to get foam insulation to put under slab- on- grade for a shop?
What grade of foam do I need for what's effectively going to be used as a garage floor?
The backstory is, we're having a barn built to use as storage and work space, and it
seems shortsighted to NOT put in the tubing for hydronic heating. No immediate heating
plans, (as in, this is a 'storage' building until the permit's signed off, and probably for a while after)
but we have room for a geothermal field and also lots of maples that are going to eventually
be removed...
Thanks!
t
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Welcome to the forums, Toby!
It depends on how thick of a slab you will be pouring and what kind of traffic the building will see. If it's a thin (4 inch or less) slab and will be seeing foot and/or light duty vehicle traffic, just about anything (10 to 30 psi) will hold up. For a thicker slab, or commercial vehicle traffic (heavy/super duty truck, tractors, etc.), a higher compressive strength product (over 30 psi) is advised. Naturally, the higher the strength spec, the higher the cost per square foot, so don't over-spec the insulation or you will pay dearly for added strength you may never need.
The only grade you are going to find at the big box stores is the standard-strength stuff. The higher strength products are not considered a DIY product, so they will have to be sourced through a commercial building supply house. The least expensive path to this end is usually having an order drop-shipped to your site or to the nearest distributor. Being close to Seattle, you should have no problem finding a dealer. That being said, if you have a trailer large enough and the time to go get the material, you could save a decent amount on freight charges, especially if the dealer is only a few miles away.