Sealcoating seals the small cracks that can turn into large cracks and prevents water from seeping down to the base material. The dark black color of newly applied sealcoat improves the appearance of new and old asphalt.
New sealcoating can preserve the resilience of asphalt surfaces and help hide small cracks, patches and rough spots as well as making traffic lines more visible. Sealcoat that is applied correctly makes your asphalt look cleaner because rain washes dirt and debris easily away from the smooth, non-porous surface.
Sealcoating helps protect the asphalt from the sun as well as the harmful effects of chemical spills such as oil and gasoline. Asphalt sealcoating fills surface voids, which reduces exposure to oxygen and UV rays and reduces the depth to which oil or gas can penetrate the asphalt.
Sealcoating acts as a waterproofing agent, minimizing the rate at which water enters the asphalt. Sealcoating asphalt prevents the seepage of water and moisture from rain and snow, thus preventing damage from freeze thaw cycles.
Sealcoating provides an attractive black surface that is ideal for painting lines and other markers. Sealcoat brings a dark black color to the asphalt. The blacker it is, the more heat the asphalt draws from the sun. The hotter the asphalt gets, the more pliable it becomes, which helps it to withstand traffic without cracking.
Sealcoating leaves a smooth, clean surface ideal for sweeping, which lowers cleaning costs. Sealcoating fills surface voids, which reduces exposure to oxygen and UV rays and reduces the depth to which oil or gas can penetrate the asphalt. It acts as a waterproofing agent, minimizing the rate at which water enters the asphalt.
Sealcoating costs pennies a square foot compared to the dollars needed to repair or replace damaged asphalt.The intrusion of moisture into asphalt accelerates its deterioration and is strongly related to asphalt distress.
Sealcoating seals the asphalt pavement, preventing the oxidation and erosion of the top layer and replaces fine particles lost from the asphalt surface due to oxidation on older pavements. It also resists gas, diesel fuel, oil, salt and chemical penetration which will break down the bond between the aggregate and the liquid asphalt.
The price of asphalt will always be affected by crude oil prices, which fluctuate when supplies vary. Sealcoating preserves asphalt for pennies per square foot, verses costly asphalt repairs.
Sealcoating an asphalt driveway every three years not only will make it look better, it actually will make it last longer. Sealing shields paving from the sun’s ultraviolet rays, which can deteriorate the binder and expose the aggregate. Sealcoating also prevents water and ice from getting into the paving and causing it to crumble.
The sealcoating materials and crack-filling products available to do-it-yourselfers are not as good as those available to the trade.
For most of you, choices will be limited to what’s available at your local home center or hardware store. Many larger cities have a distributor of asphalt coating products used by contractors. You may be able to purchase these professional-grade sealers and fillers, but remember that contractors buy in bulk. Most pro-grade sealers come in 55-gallon drums, not the 5-gallon buckets you’ll find at the home center. If you want to get the top-of-the-line sealer, check with your neighbors about buying enough to seal several driveways at the same time.
Most consumer-grade driveway sealers are water-based emulsions containing water, clay fillers, latex, polymers, additives and either coal tar (a byproduct of baking coal to make coke) or asphalt (a byproduct of petroleum refining). Some so-called “asphalt” emulsions also contain some coal tar.
Although significant improvements have been made in asphalt-based sealers in recent years — the use of polymers and other additives that increase durability and resistance to oil and gas, for example — coal tar products still are most popular. According to the sealer manufacturers, coal tar sealers are more durable and much more resistant to oil or gasoline penetration than asphalt-based sealers because gasoline and oil are both solvents for asphalt but not for coal tar.
Asphalt-based sealcoating products are better for air quality because they do not emit high levels of volatile organic compounds (VOCs) like the coal tar-based products do. They also smell better and are less of a skin irritant.
Both coal tar and asphalt-based products are available in plain or filled-sealer formulas. Filled sealers contain sand or other solids that fill small cracks and holes.
According to Rick Noon, technical director at SealMaster, the more solids (asphalt, coal tar, polymers, etc.) in the formula, the better the sealer quality and the more expensive it will be. You’ll get what you pay for, and you get more solids in better or best-grade sealers.
Comparing the various additives and solids used by different manufacturers is difficult because the formulas are considered proprietary information. The general rule is that the top-quality sealers will have the greatest amount of solids left on the asphalt after the liquids evaporate and cure.
The best way to determine quality is by the length of the warranty. The best-grade sealers typically have a five to six-year warranty. The better-grade sealers are generally warranted for three to four years. Plain sealers will carry a warranty of one to three years. Each manufacturer has its specific prorated warranty, which is usually clearly displayed on the label.
A fourth category of sealer has been developed within the last five years or so. It’s best described as airport, racetrack or pavement-grade. This grade of sealer has more durable acrylic polymers and lasts longer than other formulas. Some come with a 10-year warranty.
Sealer manufacturers and asphalt contractors agree that most asphalt driveways only need to be sealed about every three years. The exception would be in extremely harsh regions, such as the South or desert areas, or when the asphalt turns gray. Graying indicates that the surface is oxidizing and loosing the binder that holds the aggregate in the asphalt.
According to sealer manufacturers and engineers at the Asphalt Institute, most driveways do not need filled sealer until they have begun to develop fine cracks. This generally happens after several years. Let new asphalt cure for about a year before sealing, and then use just a plain sealer.
If you do like to seal every year to keep your driveway looking new, use
budget-priced, unsanded or nonfilled sealers. The drawback to sealing every year
is that the sealer can build up and will eventually peel, which also leads to it
being
tracked indoors. Sealer can permanently stain vinyl flooring even if you remove
it promptly. While some brands boast special ingredients to prevent tracking,
proper application and curing are key to avoiding problems.
Finally, it’s best to repair cracks and holes in the fall and let them cure over the winter. Then, come spring, hose off the driveway thoroughly and apply single coat of sealer. One thin coat of sealer, regardless of the grade, will give you the best results. Multiple coats do not protect any better and actually will cause problems by cracking and peeling.