Caring for concrete in the Sandhills
Concrete looks permanent, but small problems grow: a crack lets water under a slab, weeds widen a joint, a downspout undermines an edge. A few seasonal checks keep driveways, walks and patios in good shape for years. This calendar uses weather data from the nearest NOAA engineering station, at Fort Bragg/Simmons Army Airfield.
Spring: March to May
- Walk every slab after the last freeze. Note new cracks, scaling or chipped edges.
- Pull weeds from joints and cracks, and fill cracks with a filler made for concrete.
- Check where downspouts discharge. Water pouring onto or beside a slab erodes the base.
- Look for low spots where water puddles after rain.
Summer: June to August
The station's 1% summer design temperature is 93°F.
- If a sealer is due, apply it on a dry day within the product's temperature range, usually early or late in the day in summer.
- If you're planning new concrete, ask the contractor how they'll cure it in the heat.
- Keep heavy equipment, trailers and dumpsters off thin walks and patios.
- Rinse off fertilizer spilled on concrete; some fertilizers stain or etch it.
Fall: September to November
NOAA's data for the station lists a 100-year rainfall rate of 3.8 inches per hour, and fall storms can be heavy.
- Clean gutters and check downspout extensions before winter.
- Fill cracks before freezing weather, so water can't get in and freeze.
- Make sure soil and mulch along slab edges slope away from the house.
- If you have a septic system, check that no new concrete, parking or storage has crept onto the drainfield. Moore County's Health Department permits septic repairs, and avoiding damage is easier than fixing it.
Winter: December to February
The station's 99% winter design temperature is 24°F, and NOAA lists about 38 freeze-thaw cycles in an average year.
- Use sand or a deicer that is labeled safe for concrete. Avoid deicers on concrete less than a year old.
- Shovel promptly so snow doesn't melt and refreeze on the surface.
- Watch for water that pools and freezes on low spots; note them for spring repair.
Signs that need a contractor
Some problems are past routine care. Call a concrete contractor if you see:
- a crack wider than a pencil, or one that keeps growing from one spring to the next;
- one side of a crack higher than the other, which is a trip hazard and a sign the base has moved;
- a slab that has sunk toward the house, sending water at the foundation;
- large areas of flaking or scaling after a winter;
- hollow-sounding spots when you tap the surface, which can mean a void under the slab.
Ask the contractor what caused the problem before you talk about fixes. A cracked walk over a washed-out base needs the drainage fixed, not just a patch, and a slab near a septic tank or drainfield needs a plan that keeps heavy equipment off the system.
Every year
- Keep a record of when slabs were poured, sealed and repaired.
- Photograph cracks each spring so you can tell if they're growing.
- If a crack widens or one side rises above the other, ask a contractor to look at it before winter.