There are several advantages to using foam for signage. Foam is light making it less complicated and costly to install, it comes in varying thicknesses so foam can be used to add three dimensional depth to signage, it is more economical compared to metal materials and it has a nice professional appearance when it is new. Visually most people can’t identify material types just by looking at them making foam a suitable substitute for other materials especially when price is a driving decision making factor.
The primary downside of using foam for exterior applications like street address numbers is that it can attract critters and birds. Not only can the three dimensional depth offer birds a landing pad, in some instances it also offers them something to peck at. New foam formulations take this into consideration by adding ingredients that make it distasteful for birds. With this in mind, it’s still worth evaluating while considering material options. Although metal signage (typically aluminum) is higher priced, overall aesthetics will remain consistent over time and you will never have to be concerned with the kind of degradation that can occur with foam.