Sprayed polyurethane foam roofing systems have a number of benefits and drawbacks. If you Google "foam roofing system installation," you will see that this is the focus of a lot of online information. Here is a different spin: how a sprayed foam roofing system actually works.
When you need an epoxy, it is generally sold in a twin-tube system or a twin container system. You have to mix the two tubes or containers to activate the molecules that create the epoxy resin. A foam roof is very similar. There are two liquids that have to be mixed simultaneously as they are applied in an even layer over a roof. This is not an easy process, especially if you are attempting to apply it to a sloped roof and you are trying to prevent the liquids from running unevenly off the edges of the roof. Most roofing contractors that offer this type of roof installation do so for flat roofs, or they start at the bottom of the roof to build up to the apex of the slopes in order to avoid drips and uneven application.
Spreading and Mixing
The liquids automatically mix themselves as they are poured, but it helps to use tools to push the mixture in all directions to create more even coverage. This is definitely how it is applied on flat roofs. Sloped roofs need tools to control where the mixture goes. Once the mixture evenly coats every part of the roof, it is ready for the next step.
Application of Shingles or Other Roofing Materials
The foam mixture is both insulation and shingle glue. Before the foam can dry and solidify, shingles or other roofing options are applied. The foam helps this top layer of roofing stick in place until it can be secured with nails or screws. Once the foam roofing mixture is completely dry and very solid, it is as hard as a layer of solidified tar. Nothing is going to fall off or rip away from this layer for some time to come.
Skipping Roofing Material Layer for Texturing
The nice thing about the foam roofing system is that you do not have to add another layer to it if you do not want it. Many flat foam roofs have textured materials added to them to make the foam layer very dense. When it is that dense, no other layers are needed.
Contact a contractor who performs foam roofing system installation for more information.