Why Gunite Pools Survive Houston Hurricanes, Freezes, and Clay Soil

If you own a pool on the Texas Gulf Coast, three things test it that most of the country never thinks about: expansive clay soil that moves under the pool, hard freezes like the one in February 2021, and hurricane season every summer and fall. We have built and repaired gunite shells across Houston to Beaumont for more than 20 years, through Harvey, through Uri, through Beryl. Here is the honest engineering of what fails and what holds.

The real enemy is the soil, not the storm

Greater Houston sits on expansive clay. When it rains the clay swells, when it dries out in a Texas summer the clay shrinks, and that cycle moves everything built on it. It is the same force that cracks house slabs and driveways all over the region. A swimming pool is a large, rigid structure sitting in that moving ground, so the soil is the load a Gulf Coast pool has to be engineered for first. A pool that is going to have problems here almost always has them because the ground moved and the shell was not built to take it.

What actually fails (and what does not)

People assume gunite "just cracks." It does not. A correctly built concrete shell is one of the most stable structures you can put in expansive soil. When a shell does fail, the cause is almost always one of a short list of construction shortcuts, not the concrete itself.

Freezes: what the 2021 storm actually broke

Winter Storm Uri in February 2021 gave the Gulf Coast days of hard freeze that the region is not built for. The pools that were damaged mostly did not lose the shell. What broke was water sitting in places it should not have been during a freeze: plumbing lines, pumps and filters, tile, and coping, where freezing water expands and cracks whatever contains it. The structural gunite shell is a thick, reinforced mass and rarely freezes through. The lesson from Uri was about winterizing the plumbing and equipment, not about the concrete.

Hurricanes and floods: pressure, not wind

Wind is not what threatens a pool in a hurricane. Water is. When a storm like Harvey drops enough rain to raise the water table, the ground around a pool becomes saturated and the hydrostatic pressure underneath it climbs. An empty or lightly built pool can literally be pushed up out of the ground. A properly built gunite pool resists this two ways: its own concrete weight, and a hydrostatic relief valve that lets rising groundwater bleed off instead of lifting the shell. The single worst thing you can do during a Gulf Coast flood is drain your pool, which removes the weight holding it down exactly when the ground pressure is highest.

How to protect any pool on the Gulf Coast

• Do not drain the pool before a flood or hurricane — the water weight is what keeps it in the ground.
• Winterize before a hard freeze: run the equipment or drain the lines, and protect exposed plumbing.
• Keep the pool full and balanced; a saturated, empty shell is the most vulnerable state.
• For a new build, make sure the shell is engineered for expansive clay, poured continuously, and fully cured before finishing.
• For an aging pool, have structural cracks looked at early — a small repair on a sound gunite shell is routine.

None of this is about selling you a pool. It is the difference between a shell that lasts five decades on the Gulf Coast and one that has problems in five years, and almost all of that difference is decided by how the shell was built and how it is cared for through the seasons. That is the part we have spent 20 years getting right here.