# Urethane roof coating



## Tom Runyon (Nov 21, 2009)

We done a fair amount of acrylic coatings, but not urethane. Any thoughts, The project is a church 125 sq. metal deck, 1.5 fesco 4ply and gravle, 2'' iso with fully adhered 20 yr old EPDM. If we go with acrylic we need to clean and prime, mfg says the run off from the primer meet epa reg. With the urethane no need to prime, cost diff. $22.00 acrylic per gal. urethane $52.00 per gal.


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## Grumpy (Oct 29, 2008)

IMO Urethane is a far superior roof coating product. I'd do urethane on every roof coating job if budget would allow. It's sticker and will dry more solid than acrylic. In addition the urethane is much less prone to failure from puddles. 

Cost per gallon is important. Does your manufacturer want you to do the same number of gallons per square?

For me it's a hands down decision. What you save on primer material and labor should be enough to offset the added cost of the urethane.


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## AaronB. (Nov 23, 2008)

You should look for a wash primer to bond the surface of the EPDM before coating with any urethanes or ureas.


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## Rosco (Dec 10, 2009)

Everything said in this thread is true. The wash primer Aaron is talking about is a must. EPDM will oxidize over time, and if you run your hand on the surface your hand will turn black from the surface oxidation. This is bad.

I'm not a fan of any product promising to not require a primer, and that surface crap on aged EPDM will prevent anything from getting a good bite. 

There is no true "miracle in a drum", but there are situations where acrylic is perfectly fine to install. If your roof has very low slope, or areas of ponding, do not use it. I really like urethanes, but I'm starting to lean silicones (especially the 95% solids variety). Everything goes down with a primer when we install... mistakes are expensive so do it right the first time.


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