Concrete in Sioux Falls
Concrete in Sioux Falls has to survive one of the harder freeze-thaw climates in the country. A driveway that lasts here is mostly the result of the mix, the base and the curing.
Freeze-thaw and frost
NOAA's engineering weather data for Sioux Falls lists an average of 75 freeze-thaw cycles a year and a 50-year frost depth of 102 inches. Every cycle, water that has soaked into concrete freezes and expands. Over years, that scales and spalls the surface. Air-entrained concrete, which has tiny air bubbles to give freezing water room, resists that damage. Ask the contractor whether the mix will be air-entrained, what strength it will have, and how they'll finish the surface; overworking the surface weakens it.
Deicers
Deicers make freeze-thaw damage worse, especially on new concrete. Ask the contractor how long to wait before using deicers and which ones to avoid. Sand for traction is easier on new concrete.
Cold and heat
NOAA gives a 99% winter design temperature of −11°F and a 1% summer design temperature of 91°F. Concrete placed in cold weather must be kept from freezing while it cures; ask whether the contractor uses heated water, accelerators or insulating blankets late in the season. In summer heat, concrete sets fast and can crack if it dries too quickly; ask how they'll cure it.
Rain and drainage
NOAA lists a 100-year rainfall rate of 3.5 inches per hour. Slabs need slope to shed water away from the house, and downspouts shouldn't empty onto a driveway where water will freeze in winter. Ask where the water will go.
Base and joints
Frost heave lifts slabs that sit on wet, poorly drained soil. Ask what base material the contractor uses, how thick, and how it will be compacted. Ask where control joints will go and how deep. Get slab thickness and reinforcement in writing.
City licensing and permits
The City of Sioux Falls requires a Residential Building Contractor license for work on one- and two-family homes and townhomes that needs a building permit. Ask the contractor whether your project needs a permit and who will pull it; driveway approaches that meet the street may have their own city requirements. A contractor holding the city license has passed an open-book code exam and carries a $20,000 compliance bond and at least $300,000 of liability insurance.
Before you sign
Ask what happens if they find soft soil or old concrete under the surface. Get curing and care instructions in writing, including when you can drive on it.