One thing to consider when deciding which coating is best for your property is ponding water. For roof surfaces that are completely flat, a silicone coating is by far the best coating material. Rubber based coatings will withstand short-term ponding but will fail if water ponds for an extended time. Elastomeric coatings fail quickly in areas that pond water as these types of coatings are not designed to withstand any standing water.
The roof’s pitch is something else to consider. On roofs with any pitch, we do not recommend silicone coatings due to the slippery nature of silicone. Even for a roof with a 2:12 pitch, silicone would be extremely slippery if wet or damp posing a slip or fall hazard. On pitched roofs, we recommend a rubber based coating which gives much better traction.
Another thing to take into account is the flexibility. This allows for expansion and contraction of roof surfaces without damaging the coating. This is one of the huge advantages of rubber coatings. In fact, one of the rubber product lines we use has a 600% elasticity rating. That means a 1 foot piece of the roof coating stretches to 6 feet before it tears (or fails). The elasticity rating on the silicone product we use is 315%.
Although elastomeric coatings have a comparable elasticity rating, we never recommend this type of coating system due to so many failing through the years. This is largely due to the fact that these coatings do not handle UV rays well. Both rubber (on pitched roofs) and silicone (on flat roofs) perform much better than any elastomeric coating.