I performed a ton of research before purchasing this product. I've completely re-roofed two previous RV's so this was the first time I just needed to re-coat one. I have a 40' pusher so based on other reviews I decided I needed 3 gallons. They arrived quickly but all three cans received damage in shipping. No worries as the cans are sealed with a plastic ring that isn't going to come off without serious effort. I started by taking my RV to a car wash with an RV bay and pressure washing it as clean as possible. Next I removed all the old lap sealant from everything and replaced all my vents. I then cleaned the roof one more time by hand using Simple Green and water. From previous experience I sealed all straight and squared edges with Eternabond tape and used new lap sealant around the plumbing vent, satellite and antenna. In final preparation I wiped down the roof one last time to remove any remaining debris and taped drop clothes around the edge of the RV. I used a disposable paint tray and started by rolling the edges with a 3" roller with a 1/2" nap. Heng's almost has the consistency of latex paint so it rolls on very smoothly. I then switched to a standard 9" roller and finished the first coat which took about 1 1/2 gallons. If you look carefully at the pictures you will see a small amount of black showing through after the first coat. I let it dry overnight and returned the next day to add a second coat which took an additional gallon plus. As you can see from the pictures it turned out amazing. After all was said and done I was left with about 1/4 of a gallon. Total prep time was probably 3-4 hours and applying the product took about 1.5 hours the first coat and 45 minutes the second. I simply can't say enough good things about this product, it completely exceeded my expectations. If you've been procrastinating like I was don't wait any longer.