Most people have been given the impression that all single-ply membranes are alike and nothing can be further from the truth. Just because they are called single-ply membranes does not mean that they will perform the same.
For example, not all automobiles perform the same but they all fall under the category of automobiles..
Single-Ply roofing membranes have been installed on roofing projects for over 25 years. Some have performed well while others are doing poorly or are non-existent today, while others have recently come into the marketplace.
In designing performance characteristics in a single-ply membrane or single-ply system you have to keep in mind what elements the material is going to be subjected to.
Roofing membranes need to perform 24 hours a day, seven days a week, without resting periods. Roofing membranes are exposed to UV Rays, rain, snow, hail, standing water, micro organisms, chemical pollutants, vast temperature changes, wind and dynamic flexing, etc.