Sealing an asphalt driveway is more than just a way to make it look good. Driveway sealer blocks ultraviolet (UV) rays from reaching your asphalt. UV rays break down the binder in asphalt, graying the surface and exposing the stone aggregate. Driveway sealer also keeps water and ice out of the asphalt. The freezing and thawing of water can lead to cracks and potholes in driveway asphalt.
What's Your Driveway Sealer Made Of?
Driveway sealers are divided into two types based on the materials they contain.
Coal tar based driveway sealers are created from a by-product of burning coal to make coke for the steel industry. Coal tar driveway sealers are a popular option since they last a long time, provide better UV protection and resist gas and oil spills. On the downside, coal tar driveway sealer generates volatile organic compounds (VOCs) that are harmful to the atmospheres and can irritate the skin.
Asphalt based driveway sealers suspend asphalt particles in a water solution. Asphalt driveway sealers are better for the environment (and your skin), but they don't last as long as coal tar driveway sealers.
The More Solids, The Better
As a general rule of thumb, the more solids a driveway sealer contains, the better. Solids are the particles that are left behind when the liquid portion of the driveway sealer evaporates. More solids result in better protection and a longer lasting seal.
It can be difficult to determine the amount of solids a driveway sealer contains, but you can use the warranty as a guideline. A driveway sealer with a with a five year warranty will generally contain more solids than a driveway sealer with a one to three year warranty.
Also available are driveway sealers that use a "filled-sealer" formula. Filled-sealer driveway sealers contain special solids that help to fill small cracks in your driveway.
A Driveway Sealer Schedule
You should plan to re-seal your driveway every three years or so. If you use a driveway sealer more frequently, select a lower-grade sealer that will provide a thinner coating. A high-grade driveway sealer, used too frequently, will start to peel and lose its effectiveness.
One of the most common problems with concrete and blacktop driveways is that they tend to crack over a period of time. They can even develop cracks in them long before they should if they're not properly taken care of.
One reason to seal coat the driveway yourself would be to save on the cost of labor. This would end up saving you anywhere from $300 to $1000. A team of professional seal coaters usually consists of three people that make money based on the quantity of driveways they complete in one day.