Concrete Repair & Leveling in Clarksville, TN

Sunken, Cracked, Heaved or Worn?

Each problem tends to call for a different fix, so the first step is naming the right one.

• Sunken. A section has dropped, often next to steps, the garage or a downspout. The concrete itself may be fine; the ground under it moved.
• Cracked. Hairline or wider cracks where both sides are still level.
• Heaved or offset. One edge sits higher than the panel next to it. On a walkway or at a step, that lip is a trip hazard.
• Worn. Flaking, pitting, stains or discoloration on a slab that is still flat and solid.

They often travel together

A sunken panel often cracks, and a crack gives water a path underneath. At the free on-site estimate we look at the whole slab and where water goes around it before recommending anything.

Why Slabs Settle Around Clarksville

Concrete doesn't sink on its own. The base or soil under it washes out, compresses or shifts, and the slab goes with it.

Water is often behind it. Clarksville gets roughly 47 to 54 inches of precipitation a year, depending on the weather station^[1], and a downspout or low spot can put a lot of that right at a slab edge.

Soil plays a part. On the county's smoother uplands, the USDA's 1975 soil survey of Montgomery County describes 2 to 3 feet of wind-blown silt over reddish clay^[2]. It also notes, as a general matter, that soils which shrink and swell with wetting and drying do real damage to foundations, roads and other structures^[3]. That survey is decades old and says nothing specific about your yard, so treat it as background.

Winter adds stress. On roughly 70 days a year, Clarksville drops to freezing overnight and thaws again, the kind of cycling that can damage concrete made without entrained air^[4]. An open crack lets more water into that cycle. Our freeze-thaw and winter concrete care guide covers what helps a slab get through those months.

Settling, or something else?

Parts of Montgomery County are karst. The county's karst policy says those formations shape surface drainage and how water moves underground^[5], and the soil survey describes areas pitted with limestone sinks over cavernous limestone^[6].

A settled slab can have ordinary causes, and a sunken patio is not a sinkhole diagnosis. If you suspect a sinkhole, though, leveling is the wrong first call. The county warns that filled sinkholes can grow or re-form, and says to consult an engineer or geotechnical professional before trying to fix one^[7].

Mudjacking vs. Polyfoam Leveling

Both lift a sunken slab from below: drill holes, pump material underneath, bring the slab back toward level. The clearest differences are what goes in and how big the holes are.

Mudjacking

Traditional mudjacking pumps a grout of soil, sand or ground limestone mixed with cement under the slab. In Missouri DOT's maintenance guide the holes are about 2-5/8 inches across, and a slab is raised no more than 1/4 inch per hole at a time to avoid cracking it^[8]. The same guide says badly cracked or broken slabs can't be raised effectively.

Polyfoam leveling

Polyurethane foam goes in through much smaller holes. Oregon DOT's 2002 research report notes that conventional grout slabjacking drills 2- to 3-inch holes, while the polyurethane method it tested used holes about 5/8 inch wide^[9]. Smaller holes leave smaller patches in the finished slab.

What neither method promises

The same Oregon study found polyurethane can bring slabs to a target profile, but slabs may settle again afterward, and slabjacking by any method doesn't guarantee a slab stays put^[10]. Lifting can also open existing cracks. That report tested one proprietary polyurethane system, so read it as a caution, not a verdict either way. Whatever the method, fix what undermined the slab, often water, or you may be lifting it again.

Crack Repair and Resurfacing

If the slab is structurally sound but worn, cracked or discolored, it may only need attention at the surface.

• Crack repair fills and seals cracks so less water gets under the slab and into the freeze-thaw cycle.
• Resurfacing puts a cement overlay over the existing concrete to cover wear, minor cracks and discoloration.

What resurfacing can't do

An overlay changes the surface, not what's underneath. It won't hold up a slab that's sinking or breaking apart, so settlement has to be dealt with first or the new surface cracks along with the old slab. A crack that is still moving can also show back through an overlay.

When Replacement Is the Honest Answer

Repair only saves money on a slab worth saving. Replacement usually makes more sense when:

• The slab is broken into pieces or crumbling, not just cracked
• It keeps dropping after being lifted, because the ground is still moving
• Sections have heaved so far that lifting the rest won't make them flush
• You want a different size, layout or finish anyway

What a replacement involves

We break out and haul away the old concrete and pour new on a properly prepared base. See concrete driveways and patios and walkways for what goes into the new pour. Uneven sidewalks at a business or apartment property are covered under commercial concrete.

What Repair and Leveling Cost

Ballpark: $6 to $10 per square foot. It's a range to plan around; the price is confirmed at the free on-site visit. For what should be written on the page before you sign anything, see our guide to what a concrete estimate should itemize. What moves it:

• How far the slab has dropped and how much material it takes to raise it
• Mudjacking or polyfoam
• Whether cracks need repair or the surface needs an overlay
• Access, soil conditions and site prep

If it turns into a new pour

Removal of the old concrete and rebar or fiber reinforcement add to the price of a replacement. That estimate is itemized line by line before the pour.

Get a ballpark now with the instant estimate. Chris or Grant follows up by call or text, with a real reply within 1 business hour, to set up a free look at the slab.