Concrete Slabs in Waco, TX
Concrete slabs in Waco, TX are poured by Waco Elite Concrete for house foundations, post-tension slabs, garage floors, shops and room additions. Send the plans or the slab's size for a free estimate.
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Slab foundations on Waco's expansive clay
In McLennan County, the USDA soil survey marks Houston Black clay "Very limited" for dwellings on concrete slab, citing high shrink-swell; NRCS puts its plasticity index at 44 to 45. The City wants an investigation and a registered engineer's design for any foundation on expansive soil, or on soil with a plasticity index of 15 or greater.
Shop, garage and addition slabs
An accessory building over 200 square feet, and every detached carport, needs a Residential Accessory Structure permit, and a new foundation for a shop, storage building or addition must be engineered once it reaches 500 square feet. Steel shops and barndominiums are covered under metal building slabs, and store or warehouse floors under commercial concrete in Waco.
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(254) 309-9254How a slab foundation is built
Plans and estimate
The estimate starts from your plans. Where the City calls for an engineered foundation, the engineer's design comes first.
Footings, base and inspection
Exterior footings go at least 12 inches below undisturbed soil, and the slab sits on a 6-inch sand base under a 6 mil polyethylene vapor barrier. Inspection comes before the pour, with forms set and steel tied on chairs.
Pour and sign-off
An engineered foundation is inspected by its engineer of record before the pour, and that engineer's sealed, signed and dated letter reaches the City before the final inspection.
Call or request a free estimate any time, 24/7.
(254) 309-9254Concrete slab and foundation cost in Waco
A reinforced slab costs $7 to $11 per square foot in typical Waco figures (2024). Nationally, a monolithic slab-on-grade foundation runs $6 to $14 per square foot, about $12,000 to $28,000 for a 2,000-square-foot home (2026). These are published averages, not our prices; pads, steps and patios are in our Waco services list.
- 20 × 30 ft
- $5,500–$9,400
- 30 × 30 ft
- $8,200–$14,000
- 40 × 60 ft
- $21,900–$37,500
Typical Waco prices, 2024. Averages, not a quote.
Slab foundation questions
How thick does a slab foundation need to be for a house?
Under the International Residential Code, a concrete floor on ground must be at least 3½ inches thick. A monolithic home foundation is typically 6 inches thick in one published guide, and a residential post-tension slab typically 8. On expansive soil, the engineer's design sets the final figure.
What are the downsides of a slab foundation?
Ground movement. The county soil survey says Houston Black's shrinking and swelling can crack or buckle houses, roads, streets and sidewalks. The American Concrete Institute adds that some cracking and curling should be expected on every job, however good the design.
What is the best type of foundation for a house in Texas?
On expansive clay the best approach is often a structural slab that doesn't bear on the soil, or a post-tensioned slab. The International Building Code (2015, as quoted by the Post-Tensioning Institute) requires post-tensioned slabs on expansive soils to follow the institute's DC 10.5 standard.
How much would a 20x20 concrete slab cost?
Typical Waco figures put a 20 × 20 slab of 4-6 inch reinforced concrete at $3,600 to $6,200 (2024). Nationally, a 2-car garage floor of 20 × 20 to 24 × 24 feet costs $2,400 to $6,900 installed (2026).
Plan a slab or foundation in Waco
Foundations, post-tension slabs, garage floors and shop slabs. Ask for a free estimate at any hour.