Seal coating asphalt is crucial to keeping it in good condition. Asphalt is naturally porous, so while sealed asphalt is very durable, unsealed asphalt is prone to many kinds of damage. Exposure to ultraviolet light accelerates the aging and cracking of asphalt, and water can infiltrate the surface, freezing and cracking the asphalt from within. Spills of oil or gas can also soak down into unsealed asphalt, reacting with the binder and softening the pavement.
However, if this makes you want to run out and get your driveway or parking lot sealed right away, hold on! It's true that sealing asphalt is important, but part of proper seal coating is knowing when you shouldn't be sealing your driveway.
Don't: Within The First Six Months
When new pavement is installed, it has to cure for a few days before it can be driven on. However, what you might not know is that the asphalt is actually continuing to cure long after that, slowly hardening even further from exposure to air and sunlight. Seal coating too soon will keep the asphalt from hardening completely.
Instead: Wait Until Between Six And Twelve Months
By sealing your pavement between six and twelve months after it's first installed, you allow it to cure to the optimal hardness. Don't wait too long, either, or the asphalt will over-cure and can become too hard and prone to fractures.
Don't: When There Are Surface Cracks
There's no point to having your driveway resealed if the surface is cracked open; the cracks themselves will allow in the water and oxygen that a sealant is meant to protect against. The surface of the asphalt can't get a complete seal with cracks in it, and the damage will only get worse over time as the cracks continue to spread.
Instead: Have Cracks Filled Or Sealed
Before resealing your driveway, have your cracks filled or sealed – a contractor can determine which is better for the type of surface damage you have. Then, once this damage is repaired, seal coating can be applied to protect the surface from further damage.
Don't: If You Have Permeable Asphalt
There's one exception to the rule that seal coating is a must for asphalt: if you have installed permeable paving. This is specially-designed asphalt that is meant to allow water to soak down through it; installed over layers of aggregate and sand, the entire system works together as a filtration system.
Instead: Clean Up Spills Quickly
If you have permeable asphalt, make sure not to allow oil or gas spills to sit on it and soak into it. Since it isn't sealed, these can soften and damage the pavement.
Don't: In Cold Weather
The exact temperature at which it's too cold to seal coat a driveway differs depending on the sealant used, so it's a good idea to contact multiple contractors and see what their minimum temperature requirements are. However, a good rule of thumb is that it's definitely too cold to seal coat your driveway if the temperature will be below freezing.
Instead: Do It Sooner
If you have your driveway regularly resealed and the next scheduled seal coating is during the winter, have it done early instead of late. Winter is a particularly hard time for asphalt, and you don't want melting snow and ice to get down into the pavement in the spring.Share