Foundation Question

[K79]

Hello All,

I live in Maine where frost is a mojor concern of mine. I'm going to pour a slab 4' below the ground and build up my concrete block stand from there. My question is this:

Once I get to ground level, do I wrap my cinder blocks in some sort of waterproof wrap to keep moisture out? Do I fill the interior with the excavation I took out of the hole? Also should my foundation slab be the exact dimensions as my block stand?

Thanks all.

[AaronTheGeek]

Re: Foundation Question

Hi K79,

I work for a concrete contractor in Wisconsin and we pour a lot of foundations. Frost walls are a lot of work if your digging them in by hand. Personally I don't see the point in using frost walls for a WFO. I would just put 2" of extruded polystyrene closed cell foam insulation (available at HD) underneath a 6" slab. You would also need to bury insulation 4' out from the edge of the slab to prevent the frost from creeping underneath. Doing it this way is a lot quicker and easier IMHO.

If you use frost walls, water proofing is not needed. Sand is best for backfilling in most cases. What do you mean by the foundation slab? You don't need a slab underneath the frost walls....only a footing.

~Aaron

[K79]

Re: Foundation Question

This does sound easier. My neighbor has an excavator I was going to use. So is that what most people do for their WFO's that live in this sort of climate?

Thx

[AaronTheGeek]

Re: Foundation Question

This does sound easier. My neighbor has an excavator I was going to use. So is that what most people do for their WFO's that live in this sort of climate?

Thx

I don't think I've ever seen anyone on these forums do it this way. It is common practice to insulate almost every floating slab around here where I live. It seems most WFOs and WFO experts are in warmer climates, hence an apparent lack of knowledge on the subject. In my understanding, footings and frost walls is the old conventional method(still used widely), and floating slabs with insulation are relatively new with the advent of modern engineered foam insulation.

~Aaron