Commercial Roofing

[autec]

Has anyone had experience with Polyurethane Foam-in-Place Roofing Systems. I'm considering re-roofing a flat built-up asphalt roof with this system which consist of approximately 1 1/2&quot; of sprayed closed-cell polyurethane foam with 1&quot; of protective gravel on top. <br>
<br>
Thanks,<br>
<br>
Mark

 

[lbearden]

Hi Mark,

Our facility has used Polyurethane spray roofing systems for aprox. 13 years. While we are pleased with the systems performance, R-factor, vapor barrier, etc., there are a few things to watch out for. If any pinholes develop in the UV resistant membrane, sunlight will degrade the foam. Monthly inspections should be performed on the system.

Another potential problem is large bubbles forming in the foam. This is usually caused by moisture trapped under the original roof material. These bubbles will form in the weeks and months following the new roof installation. Sometimes one way vents may need to be installed thru the foam roof to allow moisture to exit from underneath, but would prevent moisture from being drawn in. Hope this is helpful.

Larry

 

[bumpjones]

If you leave your old roof on be very careful about trapping the moisture inside the old roof by covering it with a new one. If you trap the moisture in the old insulation it will cause your decking to corrode and in five years you will replace your &quot;new&quot; roof and decking at a conciderable expense. A lesson learned the hard way. Good luck.

 

[tucan]

First off, I am a roof consultant with 20 years of experience. The foam you are using has about an 80% failure rate. I suggest you remove down to the deck and apply a 4 ply built up roof. Johns Manville and Tremco are the two best manufactures of these types of systems. A good built up roof has a life span of 20 to 30 years.
If your foam roof is showing signs of blistering and pin holing, it is a few years from total failure.
Good luck.
Ps. I do not represent any manufacturer so my recomendations are from experience.