A New Driveway's First Sioux Falls Winter, Before the First Seal

Why so many new drives wait out a winter

The timing problem is built into the local climate. New asphalt needs at least three months to cure before sealing, according to Angi, and sealer needs nights above 50 degrees, which at Sioux Falls Foss Field means June, July and August. A drive paved in July reaches three months in October, when the normal low is 36 degrees and about 29 nights of the month fall to 50 or below. The first seal waits for the next summer, and the new surface spends its first winter bare.

That is not a problem in itself. Driveway sealing protects binder that weather has begun to strip away, and a drive in its first months still has nearly all of it. What a first winter can do is damage the surface mechanically: shovel and plow edges, heavy loads on a thawing base, and water that sits at the edges and freezes. Those risks are manageable, and most of them come down to habits.

Snow removal on soft new asphalt

Snow arrives often but mostly in modest amounts. Foss Field averages about 32 days a year with a tenth of an inch or more and about 12 with an inch or more, adding up to 44.5 inches, with December, January and March the snowiest months. That means many small clearings rather than a few big ones, and each pass of a blade is a chance to scrape a surface that is still soft. Angi's advice for new asphalt is to keep sharp objects and heavy equipment off it while it hardens.

A plastic or rubber-edged shovel is gentler than a steel one. A snowblower's skid shoes can be set so its scraper bar rides just above the surface, and a hired plow can be asked to keep its blade slightly raised on a new drive and to stay off the lawn edge, where the asphalt has no curb to hold it. Piling snow out on the lawn rather than along the drive keeps meltwater from running across the edges on every sunny afternoon.

The city's plows shape the street end of the job. During a snow alert, motorgraders work in pairs, and the second one, nearest the curb, uses a snow gate so the windrow lands at the side of the driveway rather than across it. The city notes that gates can be suspended when snow is too deep or wet for them, and that they narrow the street as the winter goes on. Residents may not push driveway snow back into the street, so the side piles grow all season.

Salt, sand and what cold does to deicer

Deicer on a new drive is mostly about traction and water. The state highway department notes that salt is effective only down to about 15 degrees and that below that, sand provides traction instead. Foss Field averages about 92 nights a year at or below 20 degrees and 26 at or below zero, so on many winter mornings salt spread on a drive does little to melt the ice. A thin layer of sand gives grip on those days, and it can be swept up in spring.

When salt is used, less is better. Brine runs into seams and joints like any other water and refreezes once the temperature drops far enough, and on about 99 days a year the surface at Foss Field crosses the freezing line. Keeping the drive clear of standing slush, so meltwater drains off before evening, matters more than which product goes down.

Water, sump lines and heavy loads in the thaw

The riskiest weeks for a new drive are the thaw weeks, not the coldest ones. March averages about 26 freezing nights but only 6 days that stay frozen, so the surface freezes and thaws on nearly 20 days that month. Snowmelt supplies the water, and the silty loess over glacial till that underlies much of the county keeps it near the surface, where it can feed ice lenses and heave. Keeping water off and out of the drive in March does more good than anything else.

Sioux Falls allows sump lines to discharge to the street gutter, a collection system or the lawn, but never to the sanitary sewer. A sump line that empties across a new drive keeps part of it wet through every thaw, so route it to the lawn instead. Downspouts that dump onto the asphalt can be extended the same way. In Harrisburg, the town also asks that sump hoses drain away from the house without creating a nuisance for neighbors.

Heavy loads should wait for firm ground. South Dakota allows road authorities to restrict loads anytime from February 15 to April 30 because thawing roads are weak, and a driveway's base goes through the same soft period. A roll-off dumpster, whose steel rails concentrate its weight on a few square inches, or a loaded delivery truck should wait until the base has drained, and plywood under a dumpster's rails spreads the load if it cannot wait.

The spring walk-through that sets up the first seal

Once the snow piles are gone and the surface is dry, walk the drive in daylight. Look at the seams where it meets the garage slab and the approach, at any line where a utility trench was backfilled, and at the lawn edges where snow piles sat. A hairline gap at a seam is common; a dip, a soft spot or a crack wide enough to catch a coin edge is worth noting for the contractor.

Cracks are easiest to fill well in the cool shoulder weeks, when SealMaster's 45 to 65 degree range applies and cracks are open wide, which makes May a good month for it. The first seal can then follow in June or July. A contractor quoting Sioux Falls sealcoating for a new drive should ask for the paving date, confirm at least three months of cure, and plan two coats with the sprinklers off for the first 24 hours.

• Seams at the garage slab and the approach: tight, or opened over winter?
• Trench lines and the area near the garage: level, or dipped?
• Edges where snow piles sat: firm, or crumbling?
• Water: does anything still drain across the drive?

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