A roof coating is usually a fluid applied to roofing material. You’ve undoubtedly seen this type of roof coating before, as it’s still the most popular and inexpensive option available.
Most roof coatings have elastic properties that allow them to stretch and bend with changing weather conditions. The problem with liquid roof coating is that the "paint” will start to crack and peel after a few years, and need to be reapplied.
What is Elastomeric Roof Coating?
Elastomeric roof coating, on the other hand, is a tough, highly flexible, rubberized roof coating that resists cracking and peeling. It’s also a better barrier against heat and UV rays. It helps keep roof surfaces cool, and in turn lowers the temperature of a building. When cured, it even forms a semipermeable membrane that prevents liquid penetration but encourages ventilation of water vapor.
In other words, although this type of coating is more expensive than typical roof coating, it begins to pay for itself after a few years due to the savings on cooling costs and the elimination of roof coating reapplication costs.
Elastomeric roof coating bonds well to cement tile, fiberglass sheeting, bonded gravel roofs, built up roofs, mobile home roofs, metal roofs, RV roofs, and older, aged roofs coated with materials like asphalt, aluminum or tar. Clean surfaces do not require primer, although old and pitted surfaces do.
Each gallon can bond to approximately 800 square feet of roofing. For uneven mineral surfaces, 2 to 3 gallons may be needed depending on porosity. Apply the second coat at right angles to the first coat.
Whatever you do, do not thin the coating. It bonds best at 50 degrees Fahrenheit and above. While still liquid, it can be easily removed with soap and water. It dries within two hours, and paint remover is needed to remove dry coats. Leftover coating should be stored in a well-ventilated location at room temperature.
What’s it made of?
Elastomeric roof coating is typically comprised of acrylic polymers, resins, fillers and titanium dioxide pigments (for whiteness and sheen). Most elastomeric coatings also include some type of dirt-resistant formulation that prevents dust and dirt from adhering to the coating (which can be a big problem with liquid coatings).
Any safety concerns?
Elastomeric roof coating is relatively safe to use. It doesn’t contain any VOCs and is non-flammable, too.
But, as with any roof coating, certain safety precautions should still be taken during application. Breathing in these fumes should be avoided at all times (VOCs or no VOCs). If the coating comes into contact with your eyes, you should rinse out your eyes and contact a Poison Control Center immediately.
Contact with the skin may cause irritation, but is not as serious, and can be cleaned with soap and water.