Dow Construction Chemicals
Elastomeric Roof Coatings
Frequently Asked Questions About Colored Coatings
Q: Why doesn’t Dow recommend the use of deep base colors in elastomeric roof coatings?
A: Deep tone colors, which are common in paint, pose several problems in the unique area of roof coatings. The first problem is that
dark colors tend to heat up more under direct sunlight. Often, this leads to faster drying, but only at the surface. In this situation,
a skin will form and moisture will be trapped within the coating. Eventually, this trapped moisture will lead to loss of adhesion
and can cause blistering. Second, because elastomeric roof coatings are optimized for their elasticity and adhesion, the tint
retention of these coatings can vary significantly from that of paints.
Q: Does Dow recommend particular colors in this application?
A: Typically, whites to pastels are appropriate for use in elastomeric roof coatings. These colors can be tinted to meet various local
and national energy regulations, and they provide a more measured cure and better overall performance.
Q: If I am manufacturing a tinted roof coating, what type of colorant should I use?
A: The best choice for roofing applications is usually a dry ground pigment. Unlike liquid predispersed colorants, dry pigments do
not contain any surfactants that can interfere with the performance of the coating. Also, dry pigments typically provide better
long-term color stability when compared to liquid colorants. If you choose to use a predispersed colorant, the maximum amount
that should be used is 2-4 oz per gallon.
Q: Which coating product might be best for a dark-colored roof coating for metal or other dimensionally stable surface?
A: A great option to consider is RHOPLEX™ VSR-50, a 100% acrylic low-VOC binder that features:
• Expanded formulation latitude to meet new VOC regulations – 50 g/l VOC up to 150 g/l VOC
• Low coalescent demand – minimum 3% required to pass Low Temperature Film Formation (40°F/70%RH)
• Multi-substrate capability – wood, aluminum, vinyl, masonry and composites
• Excellent alkali and efflorescence resistance
• Exterior durability – dirt pickup resistance, tint retention and grain crack resistance
• Masonry sealer and primer capable
Contact your Dow Construction Chemicals representative for more information on formulation and usage recommendations for
RHOPLEX VSR-50 acrylic in dark-colored roof applications.
Q: Is RHOPLEX™ VSR-50 a replacement for RHOPLEX EC-1791 in elastomeric roof coatings?
A: No. While RHOPLEX VSR-50 acrylic binder may perform better over substrates like metal when formulated in a dark color,
it is not designed to provide the same level of flexibility provided by RHOPLEX EC-1791 acrylic polymer.
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