When you are back filling a poured concrete basement and have filled all the cement tie holes and have spread tar on the exterior walls, can you just backfill with sand or should you apply an impermeable sheet to the exterior walls first?
Answer:
Under no condition would I backfill without some form of impermeable on the foundation walls. This, particularly in the Thunder Bay, Ontario area where I've been told you get a certain amount of frost in winter!
