Pros of A Polyurethane Roof Coating
Aliphatic or Aromatic?
There are two types of polyurethane roof coatings: aliphatic and aromatic. Each type is best suited for specific roofing environments and applications. Aliphatic polyurethane coatings are UV stable, hold color longer, resist dirt pick-up, and are typically used as a top coat. Aromatic polyurethane coatings are not as UV stable, cost less, and are most commonly used as a base coat in most systems.
Durability and Flexibility:
Polyurethane roof coating systems form an incredibly durable and flexible monolithic membrane layer. They can effectively withstand the daily expansion and contraction of roof structures as well as the damaging effects of ponding water. They are also more impact-resistant than other coating materials, making them ideal for use on roofs with high-traffic areas.
Adhesion Qualities:
Polyurethane coatings are best known for having outstanding adhesion. They will fully adhere to most conventional commercial roofing substrates including metal, modified bitumen, built-up roofs, spray polyurethane foam, concrete roof deck, EPDM, TPO, and other single-ply membranes.
UV Stability:
Polyurethane roof coating systems are highly reflective and UV stable. This means building owners and facility managers can save money by reducing cooling costs during the hot summer months. Minimizing the sun’s impact on the roofing surface not only helps to sustain lower energy costs, but it also reduces internal building temperatures and prolongs roof life.
Cons of A Polyurethane Roof Coating
Produces a Strong Odor:
A polyurethane roof coating emits a strong, xylene-based odor. While this odorous vapor is not harmful, it can be quite unpleasant for a building’s occupants. For buildings that have a fresh air intake HVAC system, we recommended it be set to recirculate air from within the building, or turned off completely during the installation process.
Challenging to Spray:
As with any solvent-based coating, polyurethane roof coatings can be challenging to spray and difficult on hydraulic spray equipment. Issues during the installation process are less likely to occur if the spray equipment is properly cleaned and maintained.
Shorter Shelf Life:
Single-component polyurethane coatings are constantly curing—even in the pail. Plural-component polyurethane coatings will not cure until mixed.