Savannah is flat, low and wet, and it is shaded by some of the largest street trees in the country. Water and roots cause more concrete failures here than traffic or age. Getting the grade and the base right is most of the job.
Do I need to worry about drainage?
Yes. Drainage is the first thing we plan. A summer storm can drop a great deal of rain in an hour, and on flat ground it has nowhere obvious to go. A slab needs a steady fall, about a quarter inch per foot is a common target, toward a place that can take the water: the street, a swale or a drain. Water that sits on concrete grows mildew. Water that runs under it carries the sand away.
My patio or driveway slopes toward the house. What can be done?
A slab that slopes toward the house should be corrected, because it sends storm water to the foundation or into the garage. Sometimes the slab can be lifted on the low side to reverse the fall. A channel drain cut in along the house can catch the water and pipe it away. Where neither works, the slab is replaced with the right slope. Which one fits depends on how much the fall is off and where the water can be sent.
Can tree roots crack or lift concrete?
Yes. Tree roots lift and crack concrete all over Savannah. Live oaks spread wide, shallow roots that thicken a little each year and raise whatever lies on top. Pines, sweetgums and crape myrtles do it on a smaller scale. A root does not have to be large to tilt a 4 inch walk.
Can I fix the concrete and keep the tree?
Often you can keep the tree. Options include curving or narrowing the slab to give the trunk more room, raising the new slab over the roots on a thin gravel layer, using shorter panels with more joints, or switching to pavers in the root zone. Cutting large roots close to the trunk risks killing the tree or making it unstable in a storm, so ask an arborist first. Trees in the City right-of-way are protected by ordinance and are not yours to cut.
My neighbor's new concrete sends runoff onto my property. What can I do?
Start by talking to the neighbor and showing them photos taken during rain. As a general principle, an owner is not supposed to change the natural flow so that runoff is collected and discharged onto the next lot in a way that causes damage. If talking fails, the city or county stormwater or code office can tell you whether a local rule was broken, and a lawyer can advise on a claim. On your own side, a swale or a drain along the line can help. This is general information, not legal advice.
Does sandy or soft soil change the job? Is there clay here?
Yes. Most of the Savannah area is sand, which drains and compacts well when clean but washes out easily. Low areas near marsh have soft soil, muck and a water table close to the surface. Expansive clay, the kind that swells and shrinks and breaks slabs in other parts of the country, is not the usual problem on this coast, though clay layers turn up inland toward Pooler and Rincon. On soft ground we dig out the bad material, bring in fill and compact it in thin layers.
My gravel driveway turns to mud. Is concrete the answer?
Concrete solves it, as long as the water problem is solved with it. A gravel driveway turns to mud when the stone has been pushed down into wet soil or water has no way off. Pouring over that without fixing the grade gives you a slab that settles. We shape the ground to drain, build a base and then pour. On a long rural drive, concrete near the house and road with gravel between is a fair compromise.
My patio settled over an old utility trench. Why?
The soil put back into the trench was never packed. A trench for a water, sewer or power line is often refilled loosely, and it keeps sinking for years, most of all when rain soaks it. A slab across it cracks along the trench line and dips. The fix is to dig out the loose fill, compact it in layers and re-pour that strip, or lift the slab if it is still in one piece.
Can I build a patio or slab in a flood-prone area?
Yes. Concrete itself is not harmed by an occasional flood. The design should assume water will come: a dense mix, a slab set a little above the yard, no fill that blocks the path water takes, and nothing that sends it to a neighbor. On marsh-side lots the highest tides of the year can reach the back yard. A slab that supports a building in a mapped flood zone has to meet the local flood ordinance, which sets floor heights. Ask the permit office for your lot's requirements.
Does salt air damage concrete near the marsh or the beach?
Slowly, yes. Salt carried in the air and in tidal water works into concrete and rusts the steel inside. Rusting steel swells and breaks the surface off. On Tybee, Wilmington and Skidaway Islands and along the rivers, we use a dense, stronger mix, keep the steel well below the surface and recommend a sealer. Rinsing a slab with fresh water after a storm tide helps.
Only a site visit gives a real price for your property. Estimates are free and come with a written quote. Call (912) 214-3834 or text us a photo of the area.