The Two Golden Rules When Seal Coating
There are two rules to follow when you sealcoat your asphalt. Always request two seal coats, and insist that the second coat is sprayed on, not squeegeed.

So Why Two Coats?
You get more for your buck… literally.  The main cost of a seal coat isn’t the material but rather the mobilization and cleaning required to coat your asphalt. And by cleaning your asphalt it needs to be clean and spotless. The “just wiped off on your pants and it’s clean” won’t cut it here. It needs to be “drop a piece of toast jam side down on the asphalt and pick it up and eat it without even hesitating” clean…

So once the asphalt is cleaned, the crews are set, and the barricades are in place all the expensive parts of the project are done. Since everything is taken care of, the cost to add another seal coat is just pennies more per sq ft. Once you compare the total cost of the two you’ll see the price is not that much more. The benefit to the second seal coat is that the coat will last longer and provide a great finished look, as long as the second coat is sprayed…

Why Spray The Second Coat?
The spray on seal coat is the newest tool for a pavement maintenance contractor; however, not every contractor offers this option. Not because they don’t recommend it but because their equipment can’t spray it. A lot of the machines clog and break due to the sand and other aggregates that are in the sealer. However some contractors have been able to modify their equipment like DRYCO and can now spray on the second seal coat without altering the aggregates in the sealer. After talking to property managers and comparing a spray finish to a squeegee finish the consensus is the same, the spray on seal coat is the only way to finish off a tight parking lot.

Besides Cosmetics, What Else?
One of the biggest problems with a squeegee is controlling the application rate. Because you slide the blade over the asphalt your essentially wiping away the excess sealer, which is fine for the first coat because it very porous however once the surface becomes tight that sealer does not get absorbed as quickly. Think of it as using a squeegee on your windshield. You put down the soap and as you run the squeegee over the tight glass surface all the water comes running off. So when you try to squeegee on that second seal coat, the sealer is actually running off the asphalt. The spray on seal coat fixes this problem by allowing us to control the application rate. You paid for the entire seal coat, make sure it all ends up on your asphalt.

Streak Marks Left From First Seal Coat (Click to Enlarge)

Flawless Spray On Second Seal Coat (Click to Enlarge)