08/25/2026
We lifted a sunken concrete slab with foam. Then we found out why it sank. 🛠️
Dennis in Bishopville had three things on his list: a rear deck with no spindles, a front railing with a cracked post, and a concrete landing that had settled away from his front door.
Here's what we did:
- Installed about 290 new spindles on the rear deck and stairs, roughly 200 of them notched by hand to seat inside the narrow channel of the existing top rail
- Set four new posts and rail sections at the front entry
- Lifted and stabilized the sunken landing with injection foam, then reset and repointed the brick and sealed the joint between the concrete and the brick
- Added toe kick boards and flashing tape under three slider doors
- Cut out the rotted sheathing behind the threshold and rebuilt it with exterior plywood, flashing, and AZEK trim
About that landing. Voids had opened up under the slab and it settled away from the door. Tearing it out and pouring new would have meant taking the brickwork apart too. Instead we drilled a few small holes and injected polyurethane foam made for lifting concrete (not the spray foam in a can) a little at a time until the slab came back up to level, still pitched to drain away from the house. Yes, you can lift concrete with foam. 💪
Getting the foam where it needed to go meant pulling the brick out from under the threshold, and that's where the answer was. Water is patient. It had been getting in for years where the brick, the concrete, and the entry meet. It rotted the sheathing behind the brick, and it's almost certainly what washed out the support under the landing. The easy move was to set the brick back and cover it up. Instead we showed Dennis what we found, cut the rot back to sound wood, installed new plywood and blocking, and lapped self adhered flashing into the threshold and weather barrier so water drains out, not in. The AZEK trim across the threshold and down both sides of the door is the finish. The flashing behind it is what manages the water.
Swipe through for the before and afters. Don't skip the rot photos. 👀
Dennis and his wife are happy with how it all came out, and the welcome mat is back where it belongs. Thank you both! 💙
Finds like this are exactly why we are intentional about who we hire. Our team knows what to look for, tells you the truth about what we find, and shows up when we say we will.
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