Driveway Sealants - Which products are
best for your asphalt driveway?
by Roy Barnhart for the Handyman Club of America
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. However, few
tradespeople use the best products available, so you can often still do the job
better yourself if you use the right materials — and you'll save up to 65
percent of the cost of professional maintenance.
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 con©tractors. 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
Coal tar vs. asphalt
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 pene©tration than
asphalt-based sealers because gasoline and oil are both sol©vents 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
Judging the quality of driveway sealers
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.
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.
Cost and coverage
sealers are more expensive than coal tar sealers, primarily due to safer
environmental factors (lower VOCs) and the technology (polymers, etc.) that must
be added to an asphalt-based sealer to improve its otherwise poor performance.
Low-end sealers range from $5 to $8 for a 5-gallon pail that covers about 400
sq.ft. These are usually just a thin coal tar or asphalt-based, paint-like
coating. Don't expect them to last more than one season. Unsanded or “plain”
sealers (the better grade) with heavier solid content range from $8 to $11; the
best-grade filled sealers cost about $12 to $15. Heavy-duty or racetrack-grade
sealers sell for around $20 for a 5-gallon bucket.Coverage varies between
grades. A 5-gallon bucket of low-end sealer covers around 400 sq.ft. The better
and top-grade sealers typically cover 250 to 350 sq.ft., depending on the
condition of the driveway.
Sealer manufacturers recommend applying sealer with a wide rubber squeegee
for the most uniform coverage. Pictured at left is a combination
long-handle broom/squeegee sold at most hardware stores.
It's important to fill cracks and seal expansion joints between asphalt and
other surfaces, such as concrete aprons or curbs, to keep water out and prevent
erosion of the paving base. Filled sealcoating materials will handle cracks up
to 1/8 in. wide.
Hot-applied sealers are best for filling cracks from 1/8 to 1/2 in. wide.
Pli-Stix driveway crack and joint filler, made by Dalton Industries, is the
only DIY hot-applied product. You press the coiled material into place and heat
it with a propane torch (preferably with a flame-spreading tip) or a heat gun
until it melts into the crack. Pli-Stix comes in a 1/2-in.-diameter, 30-ft.
roll. It can be stretched to fit 1/4-in.-wide cracks or doubled up to fill 1-in.
cracks. It also has a lifetime warranty.
Most consumer-grade crack sealers are cold-applied asphalt emulsions with
varying concentrations of latex and polymers. They are available in pourable
jugs for cracks up to 1/8 in. wide, caulking gun cartridges for 1/2-in.-wide
cracks, or as trowelable material for wider ones.
If a manufacturer rates its crack fillers using a good-better-best scale, get
the best quality product if you want it to hold up as long as the sealcoating
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
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.
Patching and leveling
out potholes and badly damaged areas to the base material and patch them with
packaged asphalt mix or, at a somewhat higher cost, special pothole patching
material. The specialty material typically is more flexible and easier to use.
The patches even work in wet conditions and can be driven on immediately after
The best repair for really "alligatored" paving is removal and patching. But
Gator-Patch by Maintenance Inc. and Gator Pave by SealMaster can
stabilize and level badly cracked asphalt without removing it. You apply them
like a filled sealer using a pole-mounted squeegee.
depressions from parked vehicles are nuisances because they collect water. To
fill them, use a series of 1/4-in.thick coats of patching material that's
intended for repairing alligatored pavement, or choose a preblended patching
material recommended for thin-section repairs.
You'll mix the latter with water and spread it from a feathered edge to up to
1 in. thick in 1/4-in. layers.
Sources for this article:
Armor Manufacturing, Tacoma, WA (800) 846-9125,
Bonsal American (Sakrete) Towson, MD, (800)
Dalton Enterprises (Pli-Stix) Cheshire, CT, (800) 851-5606
Gardner Asphalt, Tampa, FL (800) 237-1155
Henry Co., Kimberton, PA (800) 598-7663,
Maintenance Inc., Wooster, OH (800) 892-6701,
Neyra Industries Inc., Cincinnati, OH (800) 543-7077,
Quikrete, Atlanta, GA (404) 634-9100,
SealMaster Inc., Sandusky, OH (800) 395-7325,
UGL, Scranton, PA, (800) 845-5227
Vance Bros., Kansas City, MO (800) 821-8549