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Commercial Roofing Solutions from The Garland Company

What effects does temperature have on coatings?

Weekly FAQ - Application temps.jpg

What effect does temperature have on moisture cured coatings like White-Knight/

White-Stallion or White-Star?

Temperature will affect the curing time of a polyurethane or polyurea hybrid coatings. As a

rule of thumb, for every 18°F (7°C) rise in temperature, the curing rate will be cut in half.

More simply put, as the temperature increases, the cure time of the coating will be shorter.

What effect does humidity have on moisture cured coatings like White-Knight/

White-Stallion or White-Star?

Polyurethane or Polyurea hybrid coatings are sensitive to moisture. In fact, moisture is the

trigger, that starts the curing reaction. In general you should not apply coating when the

humidity level is over 90% because high levels of humidity can affect the properties of the

coating and can cause it to gel sooner. This rapid curing can give your coating an irregular

appearance like the photo below.


What effect does temperature and humidity have on a water based coating like


Temperatrure and humidity definitely play a role during the curing of waterborne coatings. You

do not want the relative humidity or temperature to be too high (above 90% humidity and

above 95°F (35°C) temperature) and you do not want the dark roof surface to be excessively

hot because it affects the speed at which the water and coalescing solvents evaporate relative

to each other. What this means is that the coating can dry so fast that it will form a film

before the coating is properly saturated or worked into the roof surface causing the coating to

peel up and stick to the roller as it is being applied.

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