Sprayed polyurethane foam (SPF) is common on Tucson's flat and low-slope roofs. The foam insulates and sheds water, but it breaks down in sunlight. A coating on top, usually elastomeric acrylic, silicone, or similar, is what protects it from UV. When the coating wears thin, the foam starts to weather.
Signs a recoat may be due
- The surface feels chalky and rubs off on your hand.
- You can see tan or brown foam showing through the coating.
- Small pits, often called bird pecks, or blisters appear.
- Water stands in low spots for days after rain.
- It has been several years since the last coating and you are not sure what was used.
What a roofer will usually look at
- Whether the foam underneath is dry and sound, or wet and needs cutting out.
- Coating type and thickness, since some coatings bond only to the same type.
- Drainage at scuppers, canales, and low spots.
- Edges at parapets, AC and cooler curbs, and penetrations.
A recoat is often less work than a replacement when the foam is still sound. A roofer can tell you which applies after looking.
Foam roof maintenance guideFlat roof repairRoof types
Questions
Can you recoat over an old coating?
Often, if the existing coating is compatible and well bonded. A roofer will check before recommending a product.
What time of year works well for recoating in Tucson?
Many roofers prefer mild, dry weather. Ask about temperature and humidity limits for the coating they plan to use.