A concrete calendar for Delaware's capital
Dover has been Delaware's capital since 1777, and its driveways, walks and patios face the same yearly cycle as any slab in Kent County: hard rain, hot afternoons and dozens of freezes and thaws. Concrete doesn't need much attention, but it rewards a few checks each season. The figures in this calendar come from NOAA's engineering weather station at Dover Air Force Base, in town.
Spring: March to May
- Walk each slab once the last freeze has passed, and photograph any cracks next to a coin for scale.
- Look for scaling, chipped edges and spots where the surface is flaking.
- Pull weeds and grass out of joints and cracks, then fill cracks with a filler made for concrete.
- Watch where water goes during a spring rain. Puddles that sit on a slab, or water running toward the house, mark problems to fix before they grow.
Summer: June to August
The station's 1% summer design temperature is 89°F.
- If the slab is due for sealer, apply it on a dry day inside the product's temperature range; early morning or evening is usually best in July.
- Planning new concrete? Ask the contractor how they'll keep it from drying out too fast in the heat.
- Keep dumpsters, heavy trailers and moving trucks off thin walks and patios.
- Sweep or rinse off spilled fertilizer, which can stain or etch the surface.
Fall: September to November
NOAA lists a 100-year rainfall rate of 3.0 inches per hour at Dover Air Force Base, so heavy storms are part of the local pattern.
- Clean gutters after the leaves drop and make sure every downspout empties away from slabs and the foundation.
- Seal or fill open cracks before freezing weather, so water can't get in and freeze.
- Regrade soil and mulch along slab edges so they slope away from the house.
- Note any section that has sunk or tilted since spring.
Winter: December to February
The station's 99% winter design temperature is 17°F, and it averages about 51 freeze-thaw cycles a year.
- Shovel promptly so snow doesn't melt during the day and refreeze on the surface at night.
- Use sand or a deicer labeled safe for concrete, and keep deicers off concrete poured within the past year.
- Watch for ice that forms in the same low spots after every thaw; mark them for spring repair.
- Avoid chipping ice off the slab with a metal tool.
When to call a contractor
Some problems are beyond routine care. Get a concrete contractor to look if you see:
- a crack wider than a pencil, or one that grows from one spring to the next;
- one side of a crack sitting higher than the other, which is a trip hazard and a sign the base has moved;
- a slab that has settled toward the house and now sends water at the foundation;
- large areas of scaling after a single winter;
- hollow-sounding spots when you tap the surface.
Ask what caused the damage before you talk about repairs; a patch over a washed-out base won't last. Before you hire, look the company up in the Delaware Department of Labor's list of registered construction contractors. Delaware law requires construction service businesses to register with its Office of Contractor Registration before beginning work in the state.
Every year
- Keep a note of when each slab was poured, sealed and repaired.
- Compare this spring's crack photos with last year's.
- Fix drainage problems first; most concrete damage starts with water.