Driveway sealer is a type of sealant used to cover concrete after a driveway has been built. This sealant forms a protective layer on top of the porous concrete to keep the concrete from cracking during sharp temperature changes; this is especially useful for preserving concrete in harsher climates where the changes between winter and summer are extreme.
Sealer Pails Freezing
If you buy a pail of driveway sealer and apply it, you may want to keep the leftover sealer to add another coat next year, because the sealer needs to be reapplied occasionally for full protection. If you keep this leftover sealer in the garage or another place that is not heated, however, it could freeze over the winter. Once frozen, the sealer will lose its bonding capabilities and you will not be able to use it again.
Sealer on the Driveway
When you apply your sealer to the driveway, be sure to complete the project in weather that is well above freezing. Read the instructions for your sealer; many will specify a temperature, such as 40 degrees, that the driveway must stay above while the sealer dries. If the sealant layer freezes or becomes too cold before it has fully cured, it will not be able to properly bond with the driveway.
Sealer Over Time
Over time, sealers fade away if they are not consistently reapplied. While the sealer itself may not be damaged, the concrete beneath it will become more and more vulnerable to damage. This is why many driveways, even though they are sealed, will crack or chip over time. Reapply your sealer every year or two to preserve the concrete.
If you are building a new driveway, be careful when you apply your sealer. The driveway needs time to cure properly. If you wait less than a month to put on the sealer, you will be trapping moisture against that sealer. When the weather reaches freezing conditions, this moisture will expand and start cracking the concrete, despite the layer of sealant. Always wait for your driveway to fully cure and dry before adding the sealer coating.