Is sealing asphalt driveway really necessary?
Q. I bought our house new four years ago. When the house was new, the asphalt driveway was all black, but now looks gray like the road in front of my house. Neither driveway nor roadway have ever been “sealed” with an asphalt sear that I’ve seen. Is it worth the investment in my time and money to seal or have my driveway sealed with an asphalt sealer? Do you have any information that shows that sealing one’s driveway yields a longer driveway life?
A. I can’t put my hands on any scientific life cycle cost comparison data for periodic sealing asphalt driveways because I don’t have to. It’s sort of like changing the oil in your car after three thousand miles of driving or painting peeling woodwork – it comes under the heading of preventative maintenance. Coating a driveway with asphalt sealer not only looks good, but would postpone the day when a repaving job would be needed.
Asphalt driveways and roads are made from a material combining gravel with hot asphalt and rolling it into a smooth surface. When the asphalt cools to air temperature, it becomes hard. With the smooth side facing up, it presents a relatively flat surface over which wheels and feet travel easily. It’s been in use for more than a century and enjoys wide use because it’s generally less expensive than paving with concrete – durability aside.
But since blacktop’s major binding element is asphalt and since asphalt is, among other things, weather sensitive, your driveway and our highways paved with asphalt responds to atmospheric conditions. The graying that you are noticing both on the street and on your driveway is the color of the aggregate – gravel and stone – showing through as the top film of asphalt. It is being cooked from the ultraviolet rays of sunlight and oxidized from being out in the air along with the wear and tear of tires.
You may have noticed that on hot summer days, the asphalt surface can feel soft and sometimes you’ll see road sections buckle from the heat. And, conversely, road shrink slightly when exposed to winter temperatures. This cyclic expansion and contraction coupled with surface erosion of the asphalt will eventually cause small fissures or splits to appear on the surface. This is when trouble starts.
When rainwater or melting snow drains into these small cracks and the surface freezes overnight, the expansion of the ice forming will break the surface into small chunks at that spot. On roads, couple the small broken chunks with high speed and heavy wheel traffic pounding the openings over and over and you’ve got a pot hole. Witness our own roads locally after the recent heavy rains. The process on a driveway can accelerate when weeds begin to grow in the small cracks and the roots finish the job water started.
A four-year-old driveway is a prime candidate for sealing.
It’s not rocket science to do it yourself, but I find the job messy and smelly and usually end up with a good quantity of the stuff all over me.
Successive layers of sealer can buildup on the surface over time and will become slippery when wet creating somewhat of a hazard. When that starts to happen, throw some coarse sand into the wet sealer during application as a non-skid additive.
Now, as for hiring contractors to do the job for you, be careful. One of the oldest scams going is for the “contractor” to knock on your door, with two or three guys out in the truck at the curb telling you that he has just finished a job in the neighborhood and has enough material left over to do your driveway. He says he doesn’t want to bring the opened cans of material back to the “shop” so he will give you a deal. And what a deal it is – cheaper than you could do it yourself. You check your pocket and you can cover it so you give him the go-ahead. The crew piles out of the truck and the job is done in fifteen minutes. What a deal!
Except that the goo those clowns smeared all over your driveway doesn’t dry – ever. It’s a combination of driveway sealer, creosote, old motor oil and any thick gooey hazardous waste they can get their hands on cheap or free. Now it’s yours. The police call these bad actors “travelers” because they travel from neighborhood to neighborhood preying on the unsuspecting bargain hunters right at their own homes.
Professional driveway sealers are listed in the Yellow Pages under Seal Coating or Paving and their are lots of honest people doing it.
Make sure that you get something in writing from your applicator before starting and that he has both references and a Maryland Home Improvement Commission license number painted on the side of his truck. And that’s it’s the same number as the one on his contract. It’s just an ounce of prevention.
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