In my area of MN we have a minimum frost depth protection of 42". My company usually does not do the water proofing. The water proofing contractors around here do not water proof below the basement floor when there is a frost wall. Should I go all the way to the footing?

Yes, take your waterproofing and start halfway up the side of your footing strip, over top of it and up the foundation wall about 6-10 inches above grade....
once the dirt settels cut off the excess so your left with only 2" of waterproofing above grade and your ready for your exterior finish...
if it is peel&stick your usuing (as opposed to liquid) make sure you install it in a vertical fashion... Overlap the pieces by 2" min.
if you apply the membrane horizontaly it might get pulled off and spread the seams when you backfill.

you owe me a lunch :)

If I do the waterproofing I will use peel & stick and dimple board. But why would I want to waterproof that part that is below the basement floor? I am just trying to confirm my opinion since nobody else water proofs a frost wall.

Brad,

Our opinion is, the reason we waterproof our frost walls is to protect the foam from pests or water infiltration. Although I have never personally seen any pests in my ICF walls we do it as a good idea approach. I have heard anecdotal evidence here and from other sources that has lead us to this approach. As far as water, our opinion is the soil up against our foundations is a 100 percent humidity and eventually moisture can infiltrate the foam reducing your insulative properties of the foam.

ICF Contractor

It isn't necessary. I think what you are describing is the same situation as we do with industrial buildings. There is a slab on grade and a 48" deep frost wall . We use the 8" Durisol wall and no waterproofing. I am sure the walls get very wet and even to some extent the soil under the slab near the perimeter, as moisture moves through the wall. There is no migration of moisture above.

In residential applications, the same applies. If the walls continue above grade, you need a capillary break so that water can't wick up the concrete through capillary suction.

A capillary break or anti wicking wall is not required by 2006 IRC, as far as I know, and that is what we use here in Minnesota. But I have been using house wrap to "form" the footings which should prevent wicking. Also I have been told that portland rich concrete (4000 psi ?) does not wick.

I think I will waterproof the frost wall, if given the opportunity.

Better safe than sorry!

Brad,

You are correct that a good concrete mix helps dramatically. I believe the ACI says that concrete that reaches 5000 psi and is properly consolidated is considered impervious to water. Around here we build concrete floats or "basements" under houseboats, floating bridges, and barges. Heck there is even a concrete boat race every year. One of the issues you will run into with just the cement approach is that of durability. How long will it continue to perform? Don't know because it depends on the conditions.

ICF Contractor