Step 6 · Backfill and Repair Floor
If you are using a backwater valve access box, place its sleeve over the valve now, ensuring the cover will be flush with the finished floor. Begin backfilling the hole with the previously excavated gravel or soil. Add the material in 4-6 inch layers, and use a hand tamper or a piece of 2x4 to compact each layer thoroughly. This prevents the ground from settling later and cracking your new concrete patch. Continue until you are about 4 inches from the top of the floor. Mix your ready-mix concrete in a wheelbarrow or mixing tub according to the package directions. Pour the mixed concrete into the hole, slightly overfilling it. Use a trowel to screed, level, and smooth the surface, making it flush with the existing basement floor. Let the concrete cure for at least 24-72 hours before walking on it.