Concrete Slabs
in Houston, TX

How much does a concrete slab cost in Houston?

Concrete slab installation cost is quoted per square foot, and the rate is not the same for every pour. A plain shop pad and an engineered house slab use different steel, different thickness and different site prep, so they never price alike. Five things move the number. The first three are slab size, thickness and reinforcement, whether that is wire mesh, rebar or post-tension tendons. The last two are the select fill the soil report calls for and whether old concrete has to come out first. Access matters too, because a truck that cannot reach the forms means pumping. Most callers ask about the same sizes: 20x20, 24x36, 30x40 and 40x60. We do not publish a concrete slab cost per square foot, because a number given before the soil report is a guess. Ask for the free written estimate instead and you get every line.

How thick should a concrete slab be for a shop, garage or workshop?

Thickness follows the load the floor has to carry. Four inches handles cars and light storage. Five or six inches is the normal call for a work truck, a trailer, a metal building or a barn with equipment in it. Where a car lift bolts down, or where a press or hoist lands, we thicken the slab to 10 to 12 inches at that spot and add steel around it. Tell us what is going on the floor and where it lands. A lift pocket costs almost nothing to form now and a lot to cut in later. House slab thickness is not our call. It comes off the stamped engineering with the beam depths and the steel already sized.

Do I need a permit to pour a concrete slab in Houston?

For a building, yes. A concrete slab permit comes from the City of Houston if the lot is inside city limits. If the lot is in unincorporated Harris County, it comes from the Harris County Engineering Department. Outside those two, the permit comes from whichever city or county you are in, and Fort Bend, Montgomery, Brazoria and Galveston counties all run their own offices. Different offices, different clocks, and we build the schedule around yours. Houston does exempt some small flatwork under its residential amendments, along with retaining walls under 4 feet that are not holding a surcharge. A slab that carries a building is never in that exempt bucket. On commercial work Houston will issue a Foundation Only Permit, so the pad can start while the rest of the building is still in plan review. We pull the permit and book the inspections.

Does a concrete slab need rebar, wire mesh or post-tension cable?

Each one does a different job. Wire mesh helps hold a shrinkage crack tight. Concrete slab rebar adds real tensile strength, and we use Grade 60 deformed bar. Post-tension tendons get pulled tight after the pour and squeeze the slab together, which is why they suit high-plasticity clay. We design tendon layouts to PTI DC10.5. The stamped engineering picks the system, which is worth knowing if you are worried about being upsold. The mix matters as much as the steel. Our structural mixes run 3,000 to 4,500 psi, and psi is simply the strength the mix is designed to reach. Heavier loads get a stronger mix.

Slab on grade or pier and beam: which is right for my Houston lot?

The soil report, the flood elevation and the budget decide it, in that order. A slab on grade costs less to build and is simple to maintain. Pier and beam costs more up front and gives you access under the floor. Here is the Houston decider. In the unincorporated Harris County 100-year floodplain you cannot bring in fill to raise the pad, so an open foundation on piers is often the required answer. Every foundation there has to be designed by a registered professional engineer. Inside city limits, Chapter 19 puts new structures in the 100-year or 500-year floodplain 2 feet above the 500-year flood elevation. A well drained, well designed slab lasts the life of the house. Trees, leaks and uneven moisture around the perimeter are what shorten one. Read more on our pier and beam foundations page. Send us the soil report and the flood elevation and we will tell you which one your lot wants. Call (832) 576-3278.

Why do concrete slabs crack in Houston, and does a crack mean the slab failed?

Almost every slab gets hairline cracks. Concrete shrinks as it cures, so shrinkage cracks in a concrete slab are normal. That is why we saw control joints in: the slab cracks along the line we cut. A structural crack looks different. It is wide, the two sides sit at different heights, doors stick and the floor goes out of level. The Houston driver is the clay. It swells when it is wet and shrinks when it is dry. This city averages just under 52 inches of rain a year. In 2011 the total came in at 24.57 inches. Trees are the number one cause of foundation repair work here, per the Foundation Performance Association. If a slab has already moved, see foundation repair. For surface damage, see concrete repair and restoration.