Professional Home Inspectors Advice on Driveway Sealcoating
Periodically applying a sealcoat to an asphalt driveway will not only improve its appearance but will help it last longer. A sealcoat protects the driveway from the sun’s ultraviolet rays and helps prevent water from seeping through cracks, where it can contribute to freeze-thaw damage or undermining of the driveway.
New asphalt driveways should be allowed to age a year or so before applying a sealcoat. Generally a recoating is only needed every three years in most areas; however, in sunny, hot climates or where the driveway is subject to heavy traffic, more frequent application may be required. Whether a new or existing driveway, the appearance of fine cracks is a clue it is time to apply a sealcoat. The graying of a driveway’s surface is another indication the asphalt is drying out.
If you are ready for a little hard labor you can tackle sealcoating yourself, and should be able to do a good job provided you use a premium grade product and follow the manufacturer’s directions and. When contemplating whether to do it yourself, getting an estimate from a professional sealcoating company may help in your decision.
A professional applied sealcoat may double your cost; however, your back may appreciate it. In addition, the sealcoating and crack-filling products used by most professional applicators are often better than those available at home centers.
The basic choices are either an asphalt-based product (a byproduct of petroleum refining) or coal tar (a byproduct of coal processing). Most consumer-available sealers are water-based and contain fillers, additives and asphalt. With the inclusion of special additives in asphalt-based sealers, their durability and resistance to oil and gas, which can breakdown the asphalt, has improved over the years; but coal tar products are still generally more durable and more resistant to oil or gasoline damage. From an environmental standpoint though, asphalt products are better because they do not emit high levels of volatile organic compounds (VOCs).
Product cost alone may not determine quality, as asphalt products can be more expensive depending on the amount of additives included. The best way to determine quality may be the length of the warranty. Better sealcoat products have a five to six-year pro-rated warranty.
If you decide to do it on your own, make sure your back is up to it. The amount of product required will vary depending on the type, amount of sand fillers, and the condition of the driveway. Most estimates indicate five gallons will be needed for each 250 - 400 sq. ft. But it is best to purchase a few extra returnable containers to make sure you can finish the job without interruption. Under estimating the amount needed is a common mistake, which can lead to trying to stretch it out too much, ending up with a less than uniform appearance or adequate protection.
Before beginning, all cracks over 1/8 inch need to be filled with crack filler compatible with the sealcoat product. Next, any spot residue from oil leaks or other contaminants need to be treated per the sealant manufacturer’s recommendations and the driveway needs to be power washed. Most manufacturers recommend a squeegee type applicator; however, a special brush may be needed for rough areas.
While seal coating can help maintain a driveway, there is a limit to its effectiveness in prolonging the driveway’s service life. If the original base it was installed over was not sound or it was a clay or silty soil, or if the driveway has weathered to the point that there are numerous or large cracks, resealing may have minimal value.
A sealer can cover hairline cracks and other small, isolated cracks can be repaired with success; but if the driveway has settled or heaved excessively, or cracked to the point it has “alligator” cracking as pictured below it is beyond the point where any crack repair or sealcoating will be of much help. Exposed to freeze-thaw cycle will only accelerate the damage when there is extensive cracking.
Some homeowners like to recoat their driveway every year to keep up its appearance, however, too frequent resealing won’t really provide much additional protection, and may actually lead to a buildup of the sealcoat, which ends up cracking or peeling.
Note: These tips are only general guidelines. Since each situation is different, contact a professional if you have questions about a specific issue. More home safety and maintenance information is available online at www.housemaster.com.