Roof coatings are waterproof, protective layers used in environments where wind, rain, snow, and other precipitation can damage a building’s roof. Typical applications include warehouses, chemical plants, manufacturing facilities, and commercial buildings.

Types

There are many different types of roof coatings. Choices include:

• coatings
• paints
• primers
• inks
• stains
• marking materials
• sealers or surface sealants

Coatings vary in terms of properties and chemistries. Paints include products made of enamel and lacquer. Marking materials are used for rooftop identification, while sealers are designed to seal gaps in a roof’s surface.

Specifications

Roof coatings carry specifications for technology and may be designed for specific substrate materials. Common technologies include film drying and air setting, laser fusing and laser marking, multi-component systems, reactive or moisture curing, and ultraviolet (UV) radiation. Thermoplastic roof coatings melt repeatedly when heated and solidify when cooled. Thermoset roof coatings undergo a chemical reaction during the cure cycle when heated. Depending on the technology, coatings can be used with substrates made of aluminum, steel, or other metals; fibers or fabrics; asphalt, bitumen, or coal tar; plastics, rubber, or elastomers; and concrete or masonry.

Roof coatings differ in terms of processing parameters and performance. Processing parameters include coverage, wet thickness and dry thickness, cure temperature and cure time, volatile organic chemical (VOC) content, viscosity, specific gravity, humidity, and particle size. Pot-life time, an additional parameter for roof coatings, is the time between the mixing stage and the gel stage at which a coating remains usable in the pot at 77^o F. Performance specifications include:

• conductivity
• resistivity
• dielectric strength
• index of refraction
• transmission
• operating or use temperature

Specialty roof coatings for specific applications and industries may carry additional specifications.

Features

Form, application method, color, finish, and features are important to consider when selecting roof coatings. Some products are provided as aerosols, crayons, films, liquids, markers, pastes, or powders. Others are available as inks, solids, and transfer tapes. In terms of application method, roof coatings may require electrostatic, electrocoating, or powder coating techniques. Rollers, screens, and spin or spray coating equipment are also used. Although color choices vary, there are four basic finishes for roof coatings: flat, satin, semi-gloss, and high-gloss. In terms of features, anti-slip products are available.

Related Information

CR4 Community—The Ziggurat Roofs of Bermuda

Image credit:

Liquid Rubber Europe / CC BY-SA 3.0