What are Elastomeric Coatings?
Proper film thickness is essential to achieve the desired performance in elastomeric roof coatings. In general, elastomeric roof coatings should be applied at a minimum of 20 dry mils dry film thickness (DFT) to meet the physical properties in the technical data sheet.
Correct film thickness is key to effectively protect the substrate from UV degradation. A thin coat will not have enough UV blocking and crack bridging capability. This is the reason why we tint our primers to a dark color. A dark surface will show through the coating and make a white coating look gray.
Oftentimes, contractors will sell a 2 coat system but fail to specify the total dry film thickness of the installed membrane. If in doubt, please ask us for details and clarification. They should strive to put down at least 30 dry mils to ensure they are getting at least 25 dry mils on any thin areas.
Elastomeric coatings sold in home improvement stores that are intended for masonry, stucco or brick are not designed for roofing applications. Be sure you have the right product!
Types of Elastomeric Coatings
Water-based, acrylic elastomeric roof coatings are widely used over metal roofs and spray foam roofs by contractors and building owners performing a DIY restoration. They are best used on roofs that don’t pond water.
How to Apply Elastomeric Roof Coatings
Airless spray equipment provide quick application with even coverage over uneven areas and roofs with a lot of penetrations or HVAC units. They are available in several models and can be customizable for each coating which eliminates the need to purchase additional rigs. Acrylic coatings can use a roof rig with a 2,000 psi pressure, 1.5 gpm spray rate and a 631 spray tip. Silicone coatings requires a larger rig with higher pressure and a 4.0 gpm spray rate.
Roof coating spreaders offer low cost, even coverage and quicker clean up than other application methods. With roller widths up to 40", they can cover 1200SF a minute. Special profile rollers for metal roofs. Spreaders are especially useful on projects where overspray is a concern.
Roller / Power Roller
Foam rollers can be used over flat roofs when applying primers. Long nap rollers are recommended for base coats and finish coats. Roof rigs can also be fitted with a power roller attachment to speed up the process.