If water is present on a roof in the morning, it is likely to form there again the next night unless the weather warms. So, coatings must be given adequate drying time before sundown to prevent the un-cured coating from being damaged overnight. Multiple coats cause longer drying times and can lead to moisture damage. Second coats should not be applied the same day when temperatures are below 80 degrees. Remember, liquid applied fabric membranes represent two coats and should only be installed when weather is favorable.
Primers dry more quickly than top coats.
Shaded areas and low areas on a roof present the greatest danger for moisture damage. The water in coatings and moisture in the roof migrates down the roof surface, collecting in low areas, such as around scuppers and drains. These areas may remain un-cured long after the balance of the roof is dry. At night, condensation also follows gravity and collects in the same low areas. Standing water in areas of un-cured coating can lead to the potential for failure.