I have an 11 inch diameter hole, for an old fire place chimney stack in the basement foundation. The foundation is cinder block. I have currently sealed off the hole from the outside of the basement with a overlapping sheet of
Mortar mix with a lot of clean brick, block or stone rubble is one possibility. Block the inside as you go to keep it in place until it sets and work from the outside to inside. Doesn't need anything fancy, just chunks of whatever is compatible with the mortar. HTH
Joe
That was my approach to fillign in a windo, old plumbing holes, etc. When done it is good to put a good coat of waterproofing on the outside if it will be below grade.
Harry K
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