The Dos And Don'ts Of Using Crack Fillers To Repair Bitumen Driveways

Posted on: 9 September 2015

A properly laid bitumen driveway can be a boon for any home, providing more long-term durability than a gravel driveway with less expense and inconvenience than laying a brick or concrete driveway. However, while a bitumen driveway is tough and will last many years, it is still vulnerable to the elements, as well as everyday wear and tear, and eventually you will notice cracks and pits start to appear. Repairing these cracks yourself with a specialised crack filler can be a cheap and relatively easy way to prolong the life of your driveway - however, crack fillers must be used carefully, and there are some instances in which they should not be used at all.

What is driveway crack filler, and how is it used?

Driveway crack fillers are usually made primarily from plastic polymers or resins, mixed with waterproofing agents and binders. These fillers are deceptively simple to use - when poured directly into a crack or pit in a driveway, the liquid hardens and bonds to the surrounding asphalt, leaving behind a smooth surface that is much less likely to crack further. Most crack fillers leave behind a black, glossy surface that blends in with the surrounding driveway.

To ensure that you achieve a proper, durable bond between the filler and the bitumen, you should make sure to clean out the crack or pit before applying filler, removing any debris and dirt that has collected within. You can do this with a simple garden hose, but people living in dryer areas with sandy soil may wish to use a compressed air gun to blast away small grains of sand and grit. You should also remove any loose chunks of bitumen with a small chisel.

Once the area to be filled is cleaned, you can pour the filler solution directly into the crack, stopping when the surface of the liquid is flush with the surrounding driveway. Be aware that some filler may be absorbed into the bitumen or the aggregate beneath your driveway, so two applications may be necessary. Be sure to give the first application at least 24 hours to dry before you add more filler. Once you have achieved satisfactory results, you should leave the filler to dry for at least 48 hours before walking or driving over the filled hole.

When is crack filler an unsuitable solution to driveway cracks?

While crack fillers are an excellent solution for most cracks, there are some circumstances in which they should not be used:

  • Large cracks or holes - Large areas of filler are less likely to adhere strongly to the driveway, and are more likely to crumble quickly. Some crack fillers are designed to seal larger gaps, but you may wish to have them professionally re-coated instead by a company like B & P Bitumen Repairs.
  • Alligatoring - 'Alligatoring' refers to the numerous, intersecting cracks seen on old, heavily damaged bitumen driveways, and are named after their resemblance to the rough scales of an alligator. Once this occurs to a bitumen driveway, it has likely reached the end of its lifespan, and should be replaced - crack filler cannot restore the structural integrity of such a heavily damaged driveway fully, and is likely to peel and crumble very quickly, particularly in hot weather.
  • Unsuitable weather - Crack filler provides the tightest seal when allowed to cure in dry, relatively cool conditions. Avoid sealing cracks during the height of summer, or during inclement weather, as crack filler that is exposed to too much heat or moisture will not cure fully and remain tacky to the touch.