Asphalt sealing, also known as blacktop sealing or seal coating, is a do-it-yourself project for many homeowners. Some people choose to seal their driveway for the aesthetics, while others hope to prevent damage from oil drips and damage caused by freezing weather.
In the northeastern US, fall is the most popular time of the year to seal your driveway, since summer temperatures have cooled and winter weather is drawing near. Fall temperatures make sealing work much easier, especially if you can do the sealing work before fall leaf drop makes it a hassle.
Best weather for sealing
Choose a day for sealing that is sunny and cool, instead of hot and humid. September usually offers ideal weather for asphalt pavement sealing in Pennsylvania and the Northeastern U.S.
Check (and double-check) the weather forecast to make sure you have dry weather for your sealing project. Don't risk sealing your driveway if there is any chance of rain.
Select a quality blacktop sealer that has all the characteristics your project requires and is compatible with any previously used sealer.
Previously sealed asphalt: 1-gallon per 100 square feet (1 average bucket 400 square feet).
Unsealed or rough asphalt: 1½ - 2 gallons per 100 square feet (1 average bucket 250 square feet).
Tip: Sealer always goes further when it isn't drying super fast, so take advantage of cooler weather and cool early morning temperatures. Some sealers may recommend misting the driveway with water to cool hot blacktop, but be sure to read and follow label instructions.
Some sealers come with "grit" for improved traction on finished surfaces. Agitate the sealer thoroughly to completely mix any settled grit laying on the bottom. Some sealers recommend storing full sealer buckets upside down the night before using them, but make darn sure the lids are not leaking if try this!
Mixing the sealer
You can use a long stick (like an old broom handle) for mixing, but a heavy duty power drill with a drywall bit is what has always worked best for me. A word of caution though, sealer will rise up in the bucket when the drill is turned on, so short on-and-off cycles work best to prevent overflows.
Locate some old clothes and shoes to wear while working with sealer since you may want to throw them away once you're done. Automatic clothes washers and dryers can get contaminated with sealer and stain subsequent loads of clothing with sealer.
Day 1 - Use a string line trimmer to trim back grass along driveway edges (if sod has grown out over the driveway edges it will be necessary to use a sharp spade or shovel to cutback the sod). Use a flat scoop or shovel for any mulch and soil that’s encroaching. Clean-up oil stains and vehicle drippings to improve sealer bonding in those areas. Finally, hose-off all dirt, mud and other debris to ensure a clean surface (Power washing the driveway works best). Sweep out puddles to promote drying, and allow adequate dry time before sealing (I prefer to clean and prep the driveway one day ahead of time).
Day 2 - Move any vehicles you will need in the next 24 to 48 hours out of the garage. Use crack filler to fill any cracks over 1/8-inch wide. If cracks are too numerous, it may not be feasible to fill them all with crack filler. NOTE: Some crack fillers, especially those for large cracks, may require a day of curing time before applying sealer, so read the label and plan accordingly.
Day 3 - Check the weather forecast again to make sure it isn't going to rain for at least 24 hours. Temperatures should also remain above 55-degrees Fahrenheit during the drying period, but follow the label on your specific product for recommendations.
Start sealing right after dawn. Sealer is easiest to work with early in the morning before the sun heats-up the pavement and shortens drying time, making sealer much harder to work with. Read the label on the sealer and follow all label instructions.
Seal the edges first
It may be necessary to use a big old paint brush to cut-in with sealer around pipes, corners and other places that are hard to reach with an applicator. Tip: Brushing away from objects you want to keep clean helps prevent splatters.
Applying the sealer
It speeds the sealing process if you have a second person to help mix and carry buckets of sealer, but keep in mind that full buckets of sealer are very heavy, usually over 40 pounds. Consider wearing gloves to keep your hands clean and carry a rag moistened with water for spot clean-ups.