I Live in Northern Ontario. I am building a pump house and put a 6 foot pit under the pump house where I can put water related equipment. I plan on insulating the outside of the blocks with Foam board before I back fill. I should mention that my land is all sand so as far as frost lines go, I am told we really dont have one here. The ground drains quick.
I plan on pouring a 10 by 10 pad over the pit and building a pump house shed there.
My question is before I put the foam board on the outside of the pit, should I tar the block or add any other type of waterproofing? The floor of the pit is gravel.