Author |
Message |
Randall A Chapple, AIA, SE, CCS, LEED AP Senior Member Username: rachapple
Post Number: 64 Registered: 12-2005
| Posted on Wednesday, September 12, 2012 - 11:55 am: | |
Is polyurethane an acceptable alternative for PMMA? I am working on a project that looks like a PMMA is a good fit. However, the manufacturer that has done the other roofs on the building has a polyurethane but not a PMMA therefore the question above. |
ken hercenberg Senior Member Username: khercenberg
Post Number: 335 Registered: 12-2006
| Posted on Wednesday, September 12, 2012 - 02:52 pm: | |
PMMA is a much harder material that cures much quicker than SPF. It doesn't have anywhere near the elongation of urethane. They're not interchangeable and neither option is a panacea for the myriad roofing conditions out there. I would typically be more concerned about elongation than hardness unless you're expecting roof traffic. Walking on SPF, even minimally, will tend to damage it. You already know about the bird nesting issue. There are also spray silicone alternatives that you may find are more suitable for your needs. |
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