Key Points
- SPF creates a seamless, insulating, watertight roofing system
- UV-protective coating must be maintained -- recoat every 10-15 years
- Can be applied over existing roof in many situations
- Cost: $5-$8/sq ft installed, plus $1-$2/sq ft for recoating cycles
- Best suited for commercial flat roofs with ongoing maintenance commitment
Frequently Asked Questions
What is spray foam roofing?
Spray polyurethane foam (SPF) roofing is applied as a liquid that expands and hardens into a continuous foam layer, typically 1-1.5 inches thick. It adheres directly to the existing substrate, creating a seamless, insulating, watertight surface. A protective elastomeric coating is applied over the foam to protect it from UV degradation. SPF roofing is used almost exclusively on commercial and industrial flat roofs.
How long does spray foam roofing last?
A properly installed SPF roof with regular maintenance (recoating every 10-15 years) can last indefinitely -- the foam itself does not degrade significantly if protected from UV. The coating protects the foam and must be maintained. Without periodic recoating, the coating degrades, exposes foam to UV, and the system fails. With proper recoating cycles, SPF roofs have documented lifespans of 30+ years.
How much does spray foam roofing cost?
SPF roofing typically costs $5-$8 per square foot installed. It is often less expensive than a full membrane replacement because it can be applied directly over existing roofing in many cases. The ongoing maintenance cost of recoating ($1-$2 per square foot every 10-15 years) should be factored into lifetime cost comparison.