Concrete Foundations & Slabs in Clarksville, TN

Foundations and Slabs We Pour

Nobody sees a foundation once the project is finished, but everything above it depends on one. We pour four kinds:

• Monolithic slab foundations. The slab and its thickened edge are poured as one piece.
• Stem-wall foundations. A footing goes in first, a short wall brings the top up to level, and the slab is poured inside it.
• Garage slabs. Attached or detached, built to carry vehicles every day, with drainage planned so the slab doesn't pool water.
• Shed pads. A flat, drained base for a shed, workshop or storage building, so the structure sits level on something solid.

Monolithic or Stem Wall?

Grade is a big part of it. A monolithic slab needs one excavation, one set of forms and one pour, which keeps cost and schedule down on level ground.

A stem wall usually costs more because there is more to build: footing, wall, backfill, then slab. It earns that cost when the lot slopes, when the finished floor has to sit higher than the yard, or when water needs to be kept well away from the building.

The free on-site estimate is where we see the grade, drainage and access in person, so the price reflects your actual site. If old concrete is in the way, we break it out and haul it off first.

How a Slab Gets Built Right

• Prep and base. Site prep, grading and compaction come first, then compacted gravel or crushed stone under every slab, matched to your soil and the load it will carry.
• Footings to code. Depth follows the code adopted where you live, covered below.
• Rebar or fiber. Rebar wherever real reinforcement is needed, with fiber as an option on every pour. We don't rely on wire mesh, because it's hard to hold in position during a pour and often ends up at the bottom of the slab.
• Drainage planned in. Water is directed away to help keep the slab from cracking, heaving or pooling water.
• Joints and the mix. Control joints at the correct spacing and a low water-cement ratio. No slab is 100% crack-proof, but done right it shouldn't crack early or unevenly.
• A real cure date. You're told the cure time, not just the day of the pour.

Codes, Karst and Clay Around Clarksville

Which code applies, and how deep footings go

The City of Clarksville has adopted the 2018 International Residential Code for one- and two-family dwellings^[1]. Montgomery County began enforcing the 2018 codes outside city limits on January 1, 2021^[2], and Metro Nashville has moved to the 2024 IRC^[3].

The 2018 IRC puts exterior footings at least 12 inches below undisturbed ground^[4]. That is a floor, not the local answer. The code leaves the frost line depth for each jurisdiction to fill in, so footing depth gets confirmed with the local building department^[5].

Sinkholes are part of the landscape

Montgomery County's building department calls sinkholes a common feature of the county and surrounding areas^[6]. A 2016 peer-reviewed study of the Sango area, on Clarksville's southeast side, reports that growth there has run into land subsidence, sinkhole collapse and flooding, with an average of 5.877 sinkholes per square kilometer^[7].

That affects where a slab can go. The county's sinkhole information sheet says dumping dirt or building materials in or around a sinkhole is illegal^[8], so filling one in to make room for a garage is not a shortcut.

What the soil survey says

In the USDA soil survey of Montgomery County, Baxter soils are the county's most widespread^[9]. Baxter soils are deep and cherty with a reddish clay subsoil^[10]. The survey was published in 1975, so read it as background, not a report on your lot.

The same survey makes a general point: soils that shrink and swell as they dry and wet cause much damage to building foundations^[11]. A county survey can't tell you what's under your yard, which is why the base goes in sized to the soil that's actually on site.

Pouring in Cold Weather

January is Clarksville's coldest month, with a normal low of 27.8 degrees F and about 21 days with a low at or below freezing^[12]. NRMCA says new concrete should be kept from freezing until it reaches 500 psi, about two days after placement, and protected from freeze-thaw cycles until it reaches at least 3,500 psi^[13].

NRMCA says curing should begin right after finishing and typically continue for 3 to 7 days, with the concrete kept above 50 degrees F, and concrete left to dry out can lose up to half its potential strength^[14].

What Foundations and Slabs Cost

Ballpark: $10 to $16 per square foot. The final price is confirmed at the free on-site visit, because much of what moves it depends on your site and your project:

• Soil conditions, grading and how much base the site needs
• Access for the concrete truck and crew
• Monolithic slab versus stem wall, and footing depth
• Rebar or fiber reinforcement
• Breaking out and hauling away old concrete

Questions to Ask Before Anyone Pours a Foundation

Put these to any contractor, us included:

• What goes under the slab, how thick is the base, and how is it compacted?
• How deep will the footings be, and who confirmed that number?
• Rebar, fiber or wire mesh? If mesh, how will it stay in position?
• Where do the control joints go?
• Who pulls the permit?
• What's the cure time before I can build on it or load it?
• Is your own crew pouring it, or a subcontractor?

Our answers

Here's where we stand: our own finish crews, not subs; a line-item estimate before the pour, with no change orders you didn't sign off on; permits pulled where the job needs them; one point of contact from estimate to final walkthrough; and Chris or Grant calling or texting you directly, with a real reply within 1 business hour.

Start with the instant estimate for a ballpark number. Pouring a driveway up to the new garage too? See concrete driveways. If an existing slab has sunk rather than failed, repair and leveling may fix it without a new pour.