To granule a foam roof or not to granule? That is the question…

To granule a foam roof or not to granule? That is the question…

If you’re thinking of installing a foam roof system, you’ve probably had a couple of salespeople come by with a sample cutaway of the foam with coating on top. In most instances, the foam sample you see has a granulated top-coat. Depending on whether your roof is commercial or residential, should decide whether you want the granules or not. It is my opinion that unless you have a large community of birds in your neighborhood, you should stick with just straight coating if it’s a residential application. Most coatings today are designed to “wash” themselves, meaning that the rains in the winter will keep your top-coat clean, dry & reflective. Granules in the top-coat are mainly used for commercial roofs, where there is a lot of foot traffic. Here’s the thing about the granules… when the top-coat goes on, it is wet & thick. The granules are broadcast (by hand or shovel) into the wet top-coat at 30 lbs per 100 sq ft. This leaves 15 lbs per 100 sq ft of loose granules to blow off, run off and fill your drains for the next several years. Also, when the top-coat dries, the granules collect dirt, dust, debris and all things in the air to turn your roof black over the next few years. This means your nice, shiny, reflective coating is no longer nice, shiny & reflective. As well, when you go to re-coat your roof in 10 years, you will need to pressure wash the roof, leaving loose granules all over the yard. If the company you choose to install your foam roof system applies the correct amount of coating over the foam (3 gal per 100 sq ft) you should not need a granulated system on a residential roof. In fact, if birds start pecking in your foam roof and leaving holes in the foam (which won’t leak btw) right after the roof is finished, you know they didn’t put enough coating over the foam for a 10 year warranty and if they did, they should be willing to put another coating down and add granules, because now you have a bird problem, not a coating problem. The contractor should be willing to do whatever to stop the pecking. If you have any questions regarding granules, please give me a call at (800) 878-1480. Gus.