Dealing With A Cracked Concrete Driveway - July 29th 2014
Q: We have a concrete driveway that is badly cracked and chipped. We are thinking of having a new asphalt driveway instead of concrete. Our question is can we have the asphalt laid directly over the existing drive or do we have to have all the old concrete removed?
A: Badly cracked or spalled (chipped) surfaces on concrete driveways or patios are signs of poor sub soil compaction and lack of routine maintenance. Asphalt is not a solution to putting a new surface on the driveway as asphalt requires rolling by mechanical compaction which will in turn damage the concrete underneath leaving a very unstable asphalt surface.
Badly cracked or spalled concrete should be removed and disposed of in a landfill. Do not use as fill under asphalt.
Asphalt driveways should be laid over a prepared compacted road base material consisting of crushed lime stone and lime stone dust commonly known as road base at aggregate suppliers. This can be used for patios, walkways as well as driveways.
An alternative to concrete or asphalt would be interlocking paving stones allowing good drainage and adding esthetic value to the home. The existing concrete would still have to be removed.
Maintenance of asphalt, concrete or paving stones requires sealing with proper products in order to minimize concerns of cracking and spalling.
To maintain concrete and paving stones apply a penetrating (migrating) water sealer every 3-5 years depending on the amount of sun exposure.
For asphalt maintenance apply 1st coat of coal tar sealer within two years after laying the asphalt and every three years thereafter use an acrylic latex sealer.