Why Slab Foundations Are Common in Montgomery
Most homes built in Montgomery County since the 1970s use slab-on-grade or post-tension slab foundations — they eliminate the crawl space, are cost-effective to build, and work well in Alabama's climate. However, they are directly exposed to the expansive clay soil below, with no air gap to buffer seasonal movement. When clay swells and shrinks, slabs crack, heave, and settle — often in different areas at different rates, creating the differential movement homeowners notice as sloping floors and cracked walls.
Post-Tension Slab Considerations
Post-tension slabs (containing high-strength steel cables tensioned after the concrete cures) require special repair procedures. Drilling into a post-tension slab without locating the cables first can sever them, causing catastrophic and extremely expensive failure. We use cable locating equipment before any drilling or cutting and coordinate with engineers when post-tension work is involved. Do not let any contractor work on your post-tension slab without cable detection.
Slab Repair Methods We Use
Polyurethane foam injection lifts and stabilizes sections of slab that have settled over voids — small holes are drilled through the slab, and expanding foam fills the void and lifts the concrete. Push piers can be installed through the slab to stabilize severely settled sections on larger structures. Crack injection with epoxy or polyurethane seals structural and non-structural cracks. In some cases, partial slab removal and replacement is the most cost-effective option for heavily damaged sections.
Slab Foundation Repair Cost in Montgomery
Polyurethane foam lifting for a settled section runs $1,500–$4,000 depending on slab area and degree of settlement. Push pier installation through a slab runs $1,400–$1,900 per pier. Crack injection for a standard residential slab crack runs $400–$1,200 depending on crack length and type. Full diagnosis and written estimate provided before any work begins.