Cracks in the exterior or interior walls of a home are unsettling for good reason — they usually point to something happening beneath the structure, not a problem with the wall itself. In Florida, that something is almost always sinkhole activity in the limestone bedrock underneath the property.
Why Sinkholes Form Under Florida Homes
Florida sits on a bed of limestone that's porous and prone to erosion. There are three general types of sinkholes that form here:
- Solution sinkholes form slowly as rainwater dissolves a depression directly into exposed bedrock.
- Cover-subsidence sinkholes also form gradually, as sand above the bedrock settles down into small openings in the limestone.
- Cover-collapse sinkholes form fast and are the most dangerous type. Acidic rainwater erodes the limestone from below, hollowing out a cavern that slowly grows until the thin layer of soil left on top gives way — sometimes suddenly.
Before a sinkhole fully forms, there are usually warning signs. Cracks in your walls are one of them. Others include cracks around windows and doors, sloping or uneven floors, doors and windows that stick, cracks in driveways or walkways, depressions in the yard, standing water, and fence posts or trees that start to lean.
What To Do About It
If you're seeing cracks like this, the right move is to call a foundation repair company with real sinkhole remediation experience — this isn't a problem to guess at or patch over yourself. A qualified contractor can evaluate the property, determine what type of sinkhole activity is involved and how far it's progressed, and recommend the right fix.
How It Gets Fixed
Two techniques do most of the work in stabilizing the soil and stopping the sinkhole from spreading:
Compaction grouting stabilizes the soil beneath a structure by pumping a thick cement-and-grout mixture deep into the ground through a limited-access drill. It fills the voids in the soil, increases how much weight the soil can bear, and seals the top of the limestone layer against further erosion.
Void filling addresses concrete slabs that have already been affected, injecting high-strength polyurethane foam beneath the slab (or behind a below-grade structure) to fill empty spaces and support the concrete from underneath. It cures into a solid, water-resistant mass that holds the slab steady.
Once the ground is stabilized, wall anchors are used to reinforce the walls themselves against further pressure, and masonry restoration — patching, resurfacing, and filling — brings the wall back to how it looked before.
Frequently asked questions
Are all wall cracks caused by sinkholes in Florida?
Most cracking tied to foundation movement in Florida traces back to sinkhole activity in the limestone below, but a proper evaluation is the only way to know for sure what's causing a specific crack.
How urgent is it to get cracks like this evaluated?
Sinkhole activity gets more expensive and more dangerous to fix the longer it's left alone. If you're seeing wall cracks along with any other signs — sticking doors, sloping floors, cracks in the driveway — it's worth having it looked at soon.