HOW, WHEN, AND WHERE TO USE SILICONE ROOF COATINGS.
So you’ve done your research on silicone roof coatings and have decided for yourself that you think they are the best spray applied roof coating available. What’s next? It’s time to learn the proper uses of silicone roof coatings.
How to Use Silicone Roof Coatings
There are two main functions and proper uses of silicone roof coatings. Both of the primary uses of silicone roof coatings involve coating over an existing roofing surface. Because silicone coatings are spray applied, they are not a standalone roofing system. They must be applied over another roofing system, and that system has often already been in place for many years. Whether it’s a new construction getting coated at the very beginning, or the building has been in existence for 50 years and its roof is leaking, silicone roof coatings can extend the roof life. Now let’s look at the uses of silicone coatings more closely.
The first use is to coat over an existing roof surface, or as we like to call it, Roof Coating Restoration. This method is used when the current roofing system on a building is wearing down, rusting, leaking, not performing well with regards to energy, or failing in some other way.
The Roof Coating Restoration steps in and puts a coating over the existing roofing surface, typically somewhere between 20-35 mils (2-3.5 sheets of paper) thick over the failing roof. This tiny layer of silicone coating then protects the roof from the elements, reflects UV rays back into the atmosphere, and can withstand ponding water. It truly is an amazing system.
This is not one of the initially intended uses of silicone roof coatings, but after silicone coatings were used on spray foam roofs, the coating was tested on other substrates and it performed exceedingly well. Since then, the Roof Coating Restoration process has become a major use of silicone roof coatings and has saved building owners millions of dollars by not having to rip out and replace their old roofing system.
What substrates work best with the Silicone Roof Coating Restoration System?
The primary Roof Coating Restoration candidates are metal, built-up, EPDM, TPO, PVC, and modified bitumen roofs. However, the Roof Coating Restoration system can also be applied to Hypalon surfaces, concrete, wood, OSB, and itself in the instance of a recoat. Many of these substrates can utilize the Roof Coating Restoration system without a primer, and those that do need a primer only need it in certain problem spots on rare occasions. More often than not, silicone roof coatings can be applied to a roofing surface without a primer.
The second main use of silicone roof coatings is to coat over top of sprayed polyurethane foam. The only real enemy of an SPF roof is the sun. It can withstand rain, harsh weather and extreme wind, but the sun’s UV rays break down the foam and this shortens its life. To fight this, most SPF roofs are coated with a silicone coating that is UV resistant. This coating is applied when the SPF roof is first installed, almost immediately after it cures, and is also applied every 10 or 15 years based on the original coating thickness.
Whether the coating is going on an SPF system upon original installation as a foam + coating system or 15 years after the initial install as a spray foam recoat system, application of silicone coatings over sprayed polyurethane foam is the second major use of silicone roof coatings and is what silicone coatings were originally designed to do.
Differences in the Uses of Silicone Roof Coatings
There are two general types of silicone roof coatings that are designed specifically for each use described above. The first type is a high solids silicone coating. High solids silicone coatings are designed to fill all cracks and crevices when spray applied. Their high solids content also enable them to be built up when applied, meaning they can go on thicker without blistering or defecting. High solids silicone coatings are designed for use in the Roof Coating Restoration system.
The second type of silicone roof coatings is a low solids formulation, designed for use on the SPF projects described above. When a sprayed polyurethane roof is installed, the foam is porous on the surface, almost like the surface of a golf ball. If a high solids silicone coating was installed, it would seep into every crevice of the surface and fill it in completely, which makes for a sturdy roofing system but requires significantly more coating.
In order to keep costs low when coating over foam, low solids silicone coatings were developed to be installed without filling every single dimple. This still allows for a seamless, waterproof, and UV resistant roofing surface, but saves money and requires less material.
So we’ve looked at the different uses of silicone roof coatings, the substrates to which they can be applied, and the types of silicone coatings and how they were designed for various applications. Do you have any more questions about silicone roof coatings and what they can do for you? Contact us using the button at the top of the page or subscribe to our newsletter on the right to receive monthly updates regarding everything we write about on the blog. Thanks for reading.