What to Use When Recoating a Foam Roof

Spray Polyurethane Foam

• Spray polyurethane foam is not always a necessary component of a foam-roof recoat. More often than not, a sound foam roof only needs another layer of protective elastromectric coating. Any blisters, tears, moisture-damage or general disrepair found during the pre-recoating inspection must be repaired with SPF, however. The damaged spot must be cleared away and the SPF re-applied to bring the coating back up to code.

Protective Elastometric Coating

• Most foam roofs have their protective elastometric coatings replaced five and then 15 years after the initial installation. This protective coating helps to reflect UV rays, weathering, abrasion and the general wear and tear that your foam roof stands up to. This liquid spray is often an acrylic coating but can be silicone, butyl rubber, polyurea or urethane. The type of material used often depends on cost an application needs. The coating is often applied in two layers: a base coat followed by a top coat.

Gravel

• A thin layer of gravel is sometimes applied over the SPF foam layer in place of an elastometric coating. Light-colored gravel is ideal because it reflects the heat of the sun's rays and helps to keep the roof's temperature down. Gravel is durable and weatherproof and often less expensive than elastrometric coatings. To remain an effective protectant, however, gravel material must periodically be replaced as wind and rain wears away at the layer.

Standards

• All material and methods used to re-coat your foam roof must meet with state and local building codes in your area. Do-it-yourself foam roof re-coaters are advised to apprise themselves of any updates or changes in the code before they purchase or apply any materials. The standards that each material meets will be printed on the label on the side of the container. If you are not applying or supplying the materials yourself, ask your contractor about the suitability and code-compliance of the materials used to re-coat your foam roof.