Concrete in Atlanta fails from below. Red clay, steep lots, heavy rain and big trees cause most of the problems we are called to look at. This page explains how each one affects a slab.
Do I need to worry about drainage?
Yes, more than about anything else. Atlanta gets roughly 50 inches of rain in a year, and much of it falls in short, intense storms. A new slab sheds every drop, so the water has to be sent somewhere on purpose. We plan the slope, and where needed a channel drain, a swale or a pipe, before we think about the finish. Poor drainage is what washes clay out from under slabs.
My patio or driveway slopes toward the house. What can be done?
It has to be changed, because water running toward the house ends up in the crawl space or basement. A driveway that drops from the street to the garage is very common here and cannot be re-sloped, so a channel drain is set across it in front of the door and piped to daylight. A patio that tilts toward the wall can sometimes be lifted along the house edge. If not, the section by the house is replaced with the correct fall.
Can tree roots crack or lift concrete?
Yes. Tree roots are one of the top causes of lifted walks and driveways in Atlanta, which has more tree cover than almost any large American city. Oaks, sweetgums and pines send roots just under the surface, where a slab keeps the soil moist. As a root thickens it raises the panel above it. Walks, which are thin, go first.
Can I fix the concrete and keep the tree?
In many cases you can keep the tree. The choices are to grind the raised edge, to re-pour the panel a little higher with a thicker stone bed over the root, or to curve the walk away from the trunk. Cutting a large root can weaken or kill a tree and can make it unstable. Inside the City of Atlanta, trees on private lots are protected by ordinance, so get an arborist's advice and check with the city before a root is cut.
My neighbor's new concrete sends runoff onto my property. What can I do?
Speak to the neighbor first and show them photos taken while it is raining. A simple fix on their side, such as a drain or a small curb at the edge, often ends it. If that fails, your city's stormwater or code enforcement office can tell you whether a local rule has been broken. Disputes over runoff between lots can become legal matters, so see a Georgia attorney if talking does not work. This is general information, not legal advice.
Does red clay change the job?
Yes. Georgia red clay carries weight well when it is dry and compacted, and badly when it is wet or loose. So the soft or wet clay is dug out, a layer of crushed stone is laid and compacted, and water is kept from collecting beneath the slab. Fill clay that a builder pushed against a foundation is the worst kind, and it is where most sunken slabs here are found.
My gravel driveway turns to mud. Is concrete the answer?
Concrete will fix it if the water problem is fixed with it. A gravel driveway goes muddy when the stone gets pressed down into wet clay and runoff has no path. On a hill, storms also carry the gravel to the bottom. Paving it needs a proper compacted base and a plan for where the faster runoff will go, or it will just move the mud to the end of the slab.
My patio was poured over a utility trench and has settled. Why?
The trench was backfilled loose. When a water, sewer or gas line is put in, the soil returned to the trench is rarely compacted in layers. It keeps sinking for years, and a slab across it follows it down or cracks along both sides. The repair is to lift that strip, or to cut it out, compact the trench properly and pour it again with steel bridging the gap.
Can I build a raised patio or slab in a flood-prone part of Atlanta?
Maybe, but check before you plan it. Lots along Peachtree Creek, Nancy Creek, Proctor Creek, the South River and the Chattahoochee can lie in a mapped flood zone or a stream buffer. Adding fill or raised structures there is regulated by the city or county, since it pushes flood water onto other lots. Ask the local floodplain office about your address first. A slab at ground level is normally the easier thing to get approved.
My lot is steep. Does that change how a driveway is built?
It changes most of it. On a steep lot the concrete truck may not be able to reach the pour, so the mix is pumped. The edges are thickened so they cannot be undercut. The finish is a rough broom texture across the slope. And the bottom of the drive gets a drain. Some hillside drives also need a low wall along one side to hold the bank.
The real price for your property comes from a free on-site estimate and a written quote. Call (678) 736-8780 or send us a photo of the concrete.