Summary: Asphalt sealing will be successful only if you prepare the driveway first. Cleaning and patching asphalt cracks are the first steps. High quality asphalt sealers are the finishing touch.

DEAR TIM: My asphalt driveway has seen better days. The original deep-black asphalt surface is now gray and the drive has several cracks in it. The surface is not in bad shape. What is the best sealer for the money? What do I have to do to achieve professional results? When is the best time to apply asphalt sealer? Bobbie S., Lolo, MT

DEAR BOBBIE: It sounds to me as if you have captured the perfect moment to save your asphalt drive surface. Of course if you were from the East coast, I would have said hot top drive, and had you been from the Midwest, I would have mentioned blacktop. It is fascinating how the same paving material is called different names by different people. No matter what you call it, the process to preserve and maintain it is the same.

There are two basic asphalt sealer products. One is a simple asphalt emulsion where regular asphalt is suspended in water. Water based asphalt sealers are earth-friendly as they do not cause ozone pollution. Perhaps the most popular asphalt sealer is a coal tar based product. Coal tar is a by-product distillate when coal is made into coke for the steel industry.

Coal tar asphalt sealers sport many advantages over their asphalt competitors. For one, they have built-in ultraviolet stabilizers and as such they stay blacker much longer than an asphalt-based sealer. Coal tar sealers are chemically different than asphalt and this difference allows them to resist damage from spilled gasoline, oil, brake and transmission fluids. These fluids can rapidly eat away at asphalt drives as well as asphalt sealers.

To obtain professional results when applying asphalt sealers, you need to do many things. Patience is the first thing you need to pull out of your toolbox. The preparation work can often stretch over several days and possibly a week. The driveway surface must be cleaned. You must remove all fine dirt, silt, mud, oil and any foreign material. You can pressure wash the surface, so long as you do not use so much force as to erode the asphalt surface. Pressure washers are excellent tools to deep clean cracks in asphalt drives.

Once the cracks are clean and dry, you can begin to fill them. Follow the instructions on the label of the crack filling products. Deep and wide cracks will probably need two applications as the material often shrinks as it dries. Many crack fillers insist that their products thoroughly dry before you apply a coat of sealer. It may take several days for the crack filler to become sufficiently hard so that it can be coated with sealer.

If you purchase a high quality sealer, you will not have to struggle to mix it. Most modern high-quality sealers are formulated as no-stir or easy-stir. It is important to make sure the product is mixed well and homogeneous if you want consistent color results. Your neighbors will know if you slack off when mixing any asphalt sealer. Failure to mix well results in a blotchy appearance with different shades of black. Low cost and quality sealers must be stirred very well as the resins separate from the water.

You should buy one of the highest priced products since you are a person who lets their driveway sealer wear until the blacktop turns gray. Some people prefer to have a jet-black driveway each season. These people should use the low-cost sealers that wear quickly. It is a huge mistake to install top quality sealers each year. Doing so creates layers of sealer that can actually peel over time.

The best time of year to apply asphalt sealer is when the weather is warm to hot. All too often people procrastinate, and wait until fall to seal their asphalt driveways. Virtually every sealer tells you to avoid applying it if the outside temperature will drop below 50 F during the application and drying phase. It simply makes better sense to avoid brushing up against this low temperature. I recommend that you get busy right now while the summer sun is high in the sky.

Summary: Gravel driveways have a new update. Tar and chip driveways give the look of a beautiful gravel driveway with the strength of a blacktop base to hold the colorful stones.

DEAR TIM: It is time for a new driveway at my home. Neither concrete nor traditional blacktop appeal to me. The look I desire is that of a groomed gravel drive similar to ones I often see on British television shows. But I do not want the dust that goes with gravel surfaces. Is it possible to get what I want? If so, how is it done? Cindy M., Waterloo, IA

DEAR CINDY: Don’t be too harsh on concrete and blacktop surfaces. Many people do not like the stark look of regular concrete, even if it has a handsome broom-finish or an expertly applied swirl trowel finish. Even the rich velvet-smooth appearance of a new ebony blacktop drive also can be a turn-off. But keep in mind that both concrete and blacktop can be installed with faux finishes. They can be colorized and stamped with patterns that allow them to look like brick, cobblestones, stone, etc.

The driveway you want is at my own home. For the past 15 years, I have driven up and down my eye-popping tar and driveway. It looks exactly like - well, actually better than - the driveways leading up to the gorgeous castles and country homes featured in many British TV shows. Can you imagine a deep-brown colored gravel driveway? That is what I have. How about one that is light green, red or even buff colored. Would you like a driveway that had gravel chips that have multi-colored sparkling minerals in each stone? All of this and more is possible.

When my wife and I built our new home we had the same feelings as you did. We did not want concrete or blacktop. I chose tar and chip for many reasons:

Tar and chip pavement surfaces are nothing new. In fact, they have been around for well over 100 years. The blacktop you see installed today is a hybrid of traditional tar and chip. Many years ago hot liquid tar or asphalt cement would be sprayed on a gravel surface. Within minutes, small, clean and dry stone chips would be broadcast into the liquid tar. As the tar cooled, it grabbed onto each of the stone chips. The resulting surface was nearly identical to blacktop that you see on many roadways around the nation. In fact, virtually every asphalt roadway or highway built in America prior to 1930 was done in this way. Many secondary county roadways are still paved with tar and chip. It is a time-tested paving method that is affordable and long-lasting.

But the tar and chip method of making roads was pushed aside by central mixed asphalt and blacktop plants. Blacktop today is made very much as is concrete. The ingredients are mixed at a central plant and shipped by truck to the jobsite. Blacktop can be installed in weather conditions that are not favorable for tar and chip. The installation season can be extended when using blacktop. Tar and chip is still done in many states, but it is not nearly as common as it once was.

I am astonished at the enormous business opportunity that tar and chip driveways represent. Tens of thousands of people love the look, yet I find blacktop installers ignore this demand. The equipment needed to install the tar and chip surfaces is already owned by many blacktop contractors. For residential applications the only specialized piece of equipment is a truck with an insulated tank used for transporting the hot liquid tar to the jobsite.

Onboard this truck is a small engine that is connected to a pump. The pump delivers the tar through a hose and nozzle to a trained operator. He carefully applies the hot tar to the gravel base and laborers broadcast the stone chips immediately into the liquid tar. Once all of the stone chips are applied, a powered roller no different than the one used for blacktop compacts the stones into the tar. New driveways require two of the tar and chips.

The different colored stone chips are the hardest thing to find. Mine came from gravel pits in Missouri. Visit a progressive landscape supply store. Often they have different colored decorative stone chips for garden pathways. Locate the sources of these stones and see if you can’t buy them in bulk quantities. The tar or asphalt cement is the easiest thing to find. It is sold at just about any central plant that makes blacktop. This tar is the same ingredient used to make blacktop.

Locating a tar and chip contractor is done one of two ways. Open your Yellow Pages and call each and every blacktop contractor. If you strike out, contact large paving contractors who do public roadways. They just might have a division that does smaller commercial or residential tar and chip jobs. Finally, contact the blacktop plants. Any contractor who does tar and chip must buy their tar from these businesses. Call the plants on a rainy day when they are slow. Don’t bother them on sunny days when the demand for blacktop is high.

This photo was taken on September 22, 2004, on State Route 29, just northwest of where Route 29 passes over Interstate 75. People out West see these signs each summer.

This is a rare situation where you can see the old road surface - in the center of the road - next to a fresh tar and chip application. The new tar and chip surface starts at the edge of the road on each side and extends towards the centerline about 6 feet in each direction. I assume the road crew is coming back to coat the center of the road. You should be able to determine that the thickness of the new tar and chip is no more than 1/2 inch. But it will wear like iron for perhaps 7 - 10 years.

I can’t say enough good things about tar and chip. It is an excellent surface for moderate to lightly traveled roadways.

Are you worried that a couple of thin layers of tar and chip can’t support the weight of trucks? This fire engine is parked on my driveway and its wheels are not sinking a fraction of an inch. The truck weighs 50,000 pounds or more! It is a combination aerial ladder truck and 1,500 gpm pumper! It also carries 500 gallons of water. Just that water alone weighs 4,144 pounds. Remember, tar and chip and blacktop driveways gather their strength from the crushed gravel base beneath the finished surfaces.

Summary: Blacktop or asphalt installation over concrete can be very successful. But, consider an alternative - concrete overlays. You can do this yourself or have a contractor make your driveway truly unique with stamped and colored concrete.

DEAR TIM: The surface of my concrete driveway is eroding after years of wear and tear. I am thinking about resurfacing my existing concrete driveway with blacktop. It is my intention to add two inches of blacktop to the existing concrete after all of the loose debris is removed. Is this a good idea? Do you see any problems? Are there other alternatives? Patrick O., Lexington, KY

DEAR PATRICK: What you plan to do is done on hundreds of thousands of miles of roadways and driveways each year in the USA. Blacktop can be successfully installed over concrete. But there are issues as you might expect. In addition, you do have an alternative paving method that may surprise you.

One positive aspect of installing blacktop over concrete is the concrete provides a firm base for the flexible asphalt paving. Experts who work each day in the blacktop industry, refer to blacktop as a flexible pavement. It does not have near the strength of concrete when you measure them inch for inch. The asphalt cement that bonds the pieces of sand and gravel in the blacktop can and does move over time. It is a unique material in that it possesses qualities of both a solid and a liquid.

Concrete is very similar to blacktop in that it also contains sand and gravel pieces. But the Portland cement ingredient that crystallizes and bonds tenaciously to the sand and gravel is as hard as rock. In fact, and geologist will tell you that regular concrete looks and feels exactly like a sedimentary rock called conglomerate.

Blacktop derives its strength from the base beneath it. New blacktop driveways are routinely installed over a compacted crushed-gravel base. This base stone is often eight to ten inches thick and when installed on firm compacted soil, it makes a superb foundation for the blacktop. But if your concrete driveway is crack-free and the individual slabs are not tilted, the blacktop covering will perform as well or better on it than the gravel.

But keep in mind that you may have crack problems at a later date with your blacktop. My guess is your current concrete drive has control or expansion joints at 10 - 15 foot intervals. Or perhaps there are a few random cracks and some slight displacement between the cracked pieces of concrete. If this is the case, these cracks will eventually telegraph through the new blacktop covering. Your blacktop contractor can saw cut in crisp lines in the blacktop directly over the concrete control and expansion joints if you like. These thin lines can be filled with special crack sealers.

You may have other problems. The added two inches of blacktop might cause safety issues where the driveway abuts stairs and sidewalks. The added thickness of the blacktop can reduce the riser height at stairs. A tapered two-inch lip can create a stumbling hazard when people walk from adjacent paved surfaces onto the driveway.

Keep in mind that your blacktop driveway will become a maintenance item every 3 - 5 years. To keep blacktop from degrading due to exposure to the elements and liquids such as gasoline, oil and hydraulic fluids, you must keep a coat of premium sealer on it at all times.

If I were you, I would seriously consider installing a thin concrete overlay on your driveway. You can apply a layer of cement stucco as thin as 3/8 inch that will last for another 40 or more years. It is possible to add an even thicker layer of concrete with small stones in it, but then you have the same safety issues I have already discussed.

There are professional companies that can stamp and colorize the thin overlays if you want a truly distinctive driveway. Stamped concrete is not a do-it-yourself (DIY) project unless you have lots of experience and many friends who can assist you.

The concrete overlay project is very DIY friendly as you don’t have to do the entire driveway on one day or even a weekend. You can apply the overlay to one or two sections of driveway at a time. The trick to making sure the driveway looks the same once complete lies in getting all of the materials you need at the same time. You must buy all the sand at one time and the bags of cement must be from the same manufacturer and batch.

Beware of blacktop contractors that say all will be well if they install blacktop over broken and crumbling concrete. It will look fine for awhile, but wait until you start to drive on it or heavy trucks pull into your drive. If you live in a cold climate, all sorts of cracks will appear half-way through the coldest part of the winter when the soil freezes and heaves the driveway.

If you decide to install the concrete overlay, you must make sure all loose material is removed and the concrete is slightly damp. Immediately before applying the overlay mix, paint on a thin coat of cement paint. Cement paint is made by mixing Portland cement powder with clear water.

Summary: Asphalt driveways will lose their flexibility if not properly sealed. Flexibility helps asphalt driveways to resist cracking. Asphalt sealers need to be applied within the first year and then whenever the blacktop begins to wear.

DEAR TIM: I’m a do-it-yourselfer and would like your opinion. My blacktop driveway is 3 years old and has never been sealed. It still appears black in color. My boyfriend tells me that I can wait another few years before sealing it. I have also heard that gasoline and oil can hurt blacktop. Is this true? If so, can you recommend a treatment to prevent this damage? How often should I seal my driveway?

DEAR C. O.: Hurry! Get to the local building supply store as fast as you can. You have already waited too long! Your driveway should have been sealed at some point within its first year depending upon your geographic location.

Blacktop or asphalt paving is a very interesting surfacing material. The asphalt industry actually markets the material as a flexible pavement. This claim arises from the fact that the asphalt cement, the material that holds together the small pieces of stone and sand in the blacktop, can remain pliable for a long period of time. This quality helps the asphalt or blacktop to resist cracks if installed properly.

However, asphalt which is exposed to air and sunlight will begin to loose this flexibility. The asphalt actually begins to oxidize. Ultraviolet light (UV) from the sun also helps to breakdown the asphalt cement. This is where problems begin to happen. If the asphalt oxidizes, it becomes brittle.The bond between it and the sand and stone particles(aggregate) begins to fail. The result of this process is cracking and loosening of individuals pieces of aggregate. If you live in a climate that experiences cold weather, this process is accelerated by water which enters these cracks and then freezes.

Blacktop sealers block air and sunlight from attacking the asphalt cement. There are several different types of sealers. The traditional sealers contain the same asphalt that is used in the original blacktop. The asphalt in these sealers is often mixed with water and a soapy compound called an emulsifier. This sealer tends to have the shortest lifespan and offers little or no protection from the UV rays from the sun.

Another type of sealer contains refined coal tar. These sealers offer excellent resistance to gasoline and oil. Gasoline and motor oil can actually dissolve the asphalt cement in blacktop. The coal tar sealers also contain small clay particles and an emulsifier which enables you to apply it easily. Some refined coal tar sealers are polymer modified. These added chemicals often provide, extra UV protection, richer color, and longer life.

Summary: Pothole repair of your asphalt driveway is easily accomplished with preparation and the right materials. Cold mix patching compound is the material your need. Be sure that the pothole is prepped correctly and know when asphalt sealer should be applied.

DEAR TIM: My blacktop drive is in fairly decent shape except for a few potholes. I am confident that I can do the repairs but wonder what can one do to make a permanent patch? The highway crews in my area don’t seem to have much luck as potholes seem to reappear in a short amount of time. What is the best material to use to fill holes in blacktop? What is the best way to repair cracks? Mary Ann M., Bowling Green, OH

DEAR MARY ANN: Patching holes in asphalt surfaces can be done successfully, if you have some time, purchase the right material, and a use a few basic tools. Many potholes tend to form in cold weather after a period of snow and ice is followed by a thaw. Thousands of potholes can appear overnight and spread like an epidemic. Highway crews often work in adverse weather and dangerous traffic conditions. It is unrealistic to expect perfect results when many holes need to be filled in a short amount of time.

The key to successful pothole repair is preparation, and the use of the right materials. Probably the best material to use for pothole repair is traditional hot mix asphalt. This product is made at plants that mix liquid asphalt, sand and different sized gravel into a mix that flows while it is hot. As it cools, the liquid asphalt hardens producing a very durable surface. It is not easy, nor is it feasible, for you to buy hot mix asphalt. If you buy a small amount, by the time you get home it will not be workable. You need to use a new and improved cold asphalt patching compound. It is absolutely the next best thing.

For many years, asphalt plants have made a cold patch asphalt that was intended for temporary patching purposes. This older material was difficult to work with and the asphalt binder that coated the stone particles often stripped off in a relatively short amount of time. When the asphalt disappeared, so did the patch. Fortunately, there have been some major advancements in cold patch asphalt technology. New synthetic polymer adhesive chemicals are now added to the asphalt that allow the cold asphalt patching products to produce permanent repairs when installed correctly. They are easy to use and very affordable.

The new cold patch asphalt mixes flow readily when you use them. They begin a curing process as soon as they are exposed to air and they are compacted. Thicker patches of cold asphalt are not necessarily better as they possibly will require longer periods of time to fully cure and harden.

Long lasting repairs require some minimal effort on your part. The key is the shape of the hole before it is repaired. The bottom of the hole should be as wide as the top of the hole when you begin to add the cold asphalt. Use a chisel to create vertical faces on the sides of the hole that extend down to the solid base material or down to a previous layer of solid asphalt. Be sure to remove any loose pieces of old pavement and any dust.

The minimum thickness of patching material at any edge should be one inch. The preferred thickness of the patching compound is approximately 2 inches. If you have a deep hole to repair, install angular crushed gravel in the bottom of the hole. Compact it very well with a steel tamper before you add the cold asphalt patching compounds. Once the gravel is compacted, add the cold asphalt so that it slightly above the surrounding pavement, level it and use a flat steel tamper to compact it.

Some of the new cold asphalt products maintain that they can be driven on immediately. This is true, but as each day passes, they get harder and harder. Avoid concentrated loads on fresh patches. Kick stands from bicycles and motorcycles can create dimples. Automobile tires that turn while the car is stationary can also damage a brand new patch.

Once you have completed your pothole repairs, wait at least 30 days before you apply a liquid blacktop sealer. A sealer that is applied over a fresh patch will cut off the necessary supply of air to the cold asphalt. If this happens, the patch can remain somewhat soft for a long period of time. As you wait for the cold patch to fully cure, take your time and clean out any cracks in the driveway area. Remove as much loose material as possible and fill them to within one quarter inch of the surface with new rubberized crack fillers. Wait one week and then fill the crack to the top. This two step process will help to create a smooth surface at each crack location.