Differences in Roof Coatings

Caulk Coatings

• Caulk can be used on most roof toppings that have cracks and holes in them. Caulk is made from various substances, and silicone and polyurethane are among the most commonly used. Caulk is cheap, easy to use and can be repeatedly replaced when it cracks from age or wear. Flexible caulk is a bit pricier but holds up better to extreme weather changes that cause it to expand and shrink.

Primers

• Roof repair primers help repair and coating materials adhere to the roof’s surface. Different formulas are available for flashings, valleys, vents and related roof accessories. Prior to the application of other roof coatings, primers are applied to roofs made of wood, concrete, masonry materials, plastic vinyl and metal. To properly seal the surfaces, primers have to be thoroughly dried before the application of sealants and coatings. Primers cannot be used on asphalt roofs.

Elastomeric Roof Coating

• This thick coating is flexible like caulk, but used to coat large expanses of roofing with a thick, paint-like material. The coating, which can be applied over almost any roof surface, seals leaks and is a good preventative coating to prevent leaks and extend the life of the roof. Elastomeric roof coatings are white and reflect light up to 98 percent, which can lower the temperature of the roof up to 12 degrees Fahrenheit, which saves on building cooling costs.

Seam Coatings

• The seams of roof coverings deteriorate over time, and application of seam coatings seals the gaps and prevents extensive damage from moisture and sun. The areas most prone to seam separation are the flashings around skylights, vents and pipes, crash buttons and J-rails, but it’s prudent to check any areas of the roof that show wear or rust stains and apply seam coatings as needed.

Single-Ply and EPDM

• Some of the oldest and most reliable roof coatings are elastomeric solutions made from ethylene, propylene and diene monomer. This chemical combination protects against sun, moisture and abrasion, and resists shrinkage in extremely cold climates. It comes in a variety of thicknesses and is available with or without polyester fabric reinforcements, which increase its durability.