Depending on the product and your specific application, sometimes a roller is actually advised. In the case of our 2 part epoxy floor coverings, it is the best choice. Roof coatings or other flat level surface applications can also be sometimes more easily done by roller. When it comes to surfaces with a lot of detail, or when you are trying to get a uniform texture, you will probably still find that the spray gun is the best choice. You can get an even coat and get into the crevices or grooves more easily with a hopper gun or HVLP.