Why do spray foam roofs leak from day one?
Spray foam roofs often leak or trap water because installation errors allow moisture to penetrate, which can make the saturated foam heavy enough to bow roof structures. While some minor leaks can be fixed by a roofer or patched, extensive water weight and saturation often require emergency tear-outs and expensive replacements.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Emergency tear out and replacement
- 2Attempting silicone recoating (though silicone only sticks to silicone and repair options are poor)
- 3filling mounting holes with silicone and applying a liquid polyurethane surface
- 4coating the roof with Sherwin Williams uniflex and a full silicone coating
- 5hiring a roofing company to come out and fix it
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“We had this happen at my factory about 10 years ago. 1940 concrete roof deck that was previously some type of built up tar roofing. Got sold a foam and coat roof job with embedded supports for walking paths to AC units. 12 inches of foam, leaked from day 1.”source ↗
“About 6 weeks after initial roofing job had to do an emergency tear out because the water weight held by the foam was bowing some sections of roof. Fucking nightmare.”source ↗
“If it's leaking then 10 to one they didn't do something right, if you put cover it in silicone that silicone is going to cause it to fail prematurely over its total lifespan.”source ↗
“Or just hire a roofer to come fix it for probably 3 to 400 bucks, and it might be the last you have to think about that thing for decades.”source ↗
“We have an apartment flat roof that is pooling and leaking in the bottom left corner. I was thinking to fill the mounting holes with silicone, then surfacing with liquid polyurethane.”source ↗
“That is what flat roofs do. Its a matter of time. You get a roofing company to come out and fix it. Thats the option.”source ↗
Where this came up
People with this problem also raised
- 4Why is my new house roof made with cheap materials and visible beams?
- 45How to tell if roof flashing is installed wrong
- 15How to temporarily waterproof a damaged roof until replacement
- 2Contractor ghosted me with a leaking steel shed floor
- 12How to fix a dipping flat roof that collects standing water
- 2Is a rubber roof worth it for persistent low-pitch leaks?