What Is Patio Leveling?
A concrete patio is poured against the house on fill that was placed during construction. As that fill consolidates and the clay beneath it cycles through wet and dry seasons, the slab settles. Because the outer edge is usually better supported than the edge against the house, patios commonly settle inward, reversing the slope they were poured with. That reversal is the real problem. A patio is supposed to carry water away from the structure. Once it tips back toward the wall, every rainfall delivers water to the base of the foundation and, on a home with a basement or crawl space, to the wall assembly behind it. Standing water on the patio after a storm is the visible symptom of a drainage failure. APS lifts settled patio slabs with polyurethane foam injection and, just as importantly, restores the fall away from the house. Ports are drilled through the slab, structural foam is injected into the void beneath, and each section is raised while elevations are monitored so the finished surface drains outward. The foam is closed cell and hydrophobic, so it is not degraded by the moisture that is already present in the soil under a patio, and it adds very little weight to ground that has already proven it cannot carry the load it had.
“On a patio the elevation is only half the job. If the finished slab does not fall away from the house, we have not fixed anything that matters.”
How APS Approaches Patio Leveling
- 1
Slope and elevation survey
We measure the existing fall across the patio to establish how far it has reversed and what the target slope should be.
- 2
Void mapping
We locate the consolidated fill beneath the slab so foam is placed where support is genuinely missing.
- 3
Controlled lift
Foam is injected in stages, raising each section while the slope is monitored continuously.
- 4
Drainage verification
We confirm water will run away from the house, patch the ports, and seal the joint at the wall.
When this approach is not appropriate: Patios laid as pavers or stamped sections set in sand are not lifted with foam injection. Neither are slabs that have broken into small fragments, which are assessed for replacement instead.
Frequently Asked Questions
Why does my patio hold water after it rains?
Almost always because the slab has settled toward the house and reversed its original slope. The water is not soaking in, it is being held against the foundation, which is why patio settlement is treated as a drainage issue rather than a cosmetic one.
Can you fix the slope as well as the height?
Yes, and restoring the slope is the point of the work. Sections are lifted independently and elevations are checked as the foam goes in, so the finished patio falls away from the wall.
Will lifting the patio crack it?
Foam injection raises the slab in small controlled stages precisely to avoid that. Existing cracks are documented before work begins, and where a slab is already cracked through we discuss whether lifting or replacement gives the better result.
Does the patio have to be empty?
Furniture and planters need to be moved off the sections being lifted. The crew will tell you what has to clear before the visit.