Answers to common homeowner questions about asphalt driveways.
Homeowners often have many questions about their asphalt driveways. Original Article Found Here
Why should I sealcoat the asphalt?
What about cracks in my driveway?
If you are a homeowner with an asphalt driveway
you have probably asked yourself these questions,
and they probably led to more questions, so we will
attempt to provide some answers for you.
How long will my asphalt driveway last? >top
Well that all depends... A properly constructed
and maintained asphalt driveway will probably last
20 to 30 years. “Properly constructed”
is a big factor here. Too often a driveway is the
last thing on the list when constructing a new home.
All to often if there have been overruns in construction
costs the driveway will “pay the price”.
As contractors it’s not unusual to hear a
homebuilder say “we only have $XXX left for
paving the drive. What can you do for that much?”
Of course that amount is usually less than what
is actually needed to do a proper job. Many times
premature structural failures in driveways are caused
by this scenario or in older homes perhaps the previous
owner was only concerned about low price, not high
quality, if they had the drive replaced. Unfortunately
it’s often impossible to tell how well the
driveway was constructed after the fact. One tip
would be if a new home driveway was not guaranteed
against any structural defects for at least 2 years,
or if there are areas that look rough or that hold
water. The second part of this is “properly
maintained”. If asphalt pavements
didn’t need maintenance your city street department
would be out of a job as would thousands of pavement
maintenance contractors. As we get to answers
to some more common questions proper maintenance
will become self-explanatory.
Why should I sealcoat my driveway? >top
Asphalt pavements are made up of stone
(aggregate) fine stone or sand, and asphalt cement.
The asphalt cement is what gives the pavement it’s
black appearance and is the “glue” that
holds everything together. Often I joking
answer this question in person by asking “why
do you paint the wood on your house?” It’s
obvious of course; to preserve the wood and protect
it from damage from the elements. The same is true
of asphalt pavements. Have you noticed that
new asphalt is jet black but soon begins to fade
and in a year or two has turned gray? That’s
oxidation. The effects of the sun and rain/snow
oxidizing the asphalt cement in the pavement. Given
enough time the pavement becomes brittle and has
less resistance to the loads placed on it. This
can lead to a multitude of problems. Asphalt
is a petroleum product so any other petroleum derivatives
that contact it will dissolve into the asphalt,
weakening or dissolving the asphalt’s “glue
like” properties. These substances
commonly include motor oil, transmission/power steering/
or brake fluids, gasoline, and perhaps household
solvents like some cleaners. It’s common to
see asphalt damaged by concrete cleaning products
used on a sidewalk but rinsed onto a driveway. And
the other common products mentioned can come from
anywhere; a leaking car, oiling the chain on the
kid’s bikes, spills while servicing the lawnmower,
the list is endless. A good quality sealcoating
will protect the asphalt pavement from all these
damaging factors while providing the curb appeal
of a new-looking black appearance. It’s
often overlooked that sealcoating not only seals
the harmful elements out but seals the beneficial
properties of the asphalt cement in. Many years
of research has proven that proper maintenance including
sealcoating can double the life of an asphalt pavement.
(Sealcoating is not new by any means. The first
sealcoating materials were developed in the 1930’s
for Standard Oil to help protect the pavement in
their service stations.) Because of the scope of
this subject there is another article devoted to
types of sealers, doing it yourself vs. hiring a
contractor, etc. Also see our article on why sealcoating
works and how it can save you money .
What about those cracks in my driveway? >top
Those need immediate attention. A host of problems
leading to major failure can result from the small
start of a few cracks left unattended. You may wonder
why we address this apart from sealcoating. Sealcoating
is for sealing an asphalt surface. It does nothing
of value for cracks larger than a “hairline”
or in layman’s terms the size of a pencil
lead or larger. Actual cracks in the pavement require
specialized crack sealant materials. Left alone
cracks allow moisture to penetrate the asphalt surface.
Water expands as it freezes, so moisture in the
cracks does the greatest damage in the winter months.
But before you breathe a sigh of relief because
you live in a warm area, moisture penetration does
great damage to pavement no matter what the temperature.
It just does more damage faster in freezing conditions.
“Homeowner grade” crack sealants are
always cold applied and must dry. (Contractors use
a superior method with hot-applied materials that
set as soon as they cool). The main issue in sealing
cracks is that they MUST be clean, dry, and have
no vegetation present prior to any sealing. Homeowners
should always shop for a sealant containing the
highest possible amount of rubber. The rubber
allows the sealant to expand and contract with the
pavement. Cheaper crack “fillers” are
hard when cured and as the pavement moves they will
separate from the asphalt, and allow moisture to
penetrate again.
What about these ugly stains? >top
Be careful. One way to prevent stains is to sealcoat the pavement in the first place, but depending on the type of stain the cure can be more damaging than the illness. Be careful to read the label of any “driveway cleaning” product. Many contain solvents. ANY solvent will damage the asphalt pavement and should be avoided, even if the product says it’s for driveways. Often for oily stains the best approach is a biodegradable cleaner (like Simple Green or similar), if those are not readily available plain dishwashing soap will do. Mix a soapy water solution, apply to the stain and let stand for a few minutes, then get a good scrub brush and apply a liberal amount of “elbow grease” and rinse thoroughly. Take note if the scrub brush begins to loosen stones in the asphalt. If this happens, stop and rinse. That is an indication that whatever stained the drive has already weakened the asphalt and you could cause more damage trying to remove it. Contractors have a variety of products made for priming stains before applying sealcoating, however these may not be available to home owners and depending on the type of stain, sealcoating may not adhere to the stained areas. This is a situation where you might want to do a test area if you were sealing yourself to see if the sealer would adhere (apply according to directions, wait 2-3 days, then scuff at the sealer with your shoe or a stiff brush. If it loosens from the stain you may need professional help.
We hope this gives you some basic answers to the
questions many people have.