Both of those factors combine to determine how high the end of the structure will be over your patio or deck. You always want to know enough about the item that you're purchasing so when the salesman tells you a blatant lie you are knowledgeable enough to know and counter it. Finally, if you decide to have a professional install your awning, make sure you have a discussion about the mounting surface and the dimensions of the area where you want it installed. It will increase the longevity of your investment by leaps and bounds. The installer will likely ask you about what the material that the surface is made out of, because the procedure for installation on brick is very different from vinyl siding and a stud backing. It's really excellent stuff that you should make sure you're getting with your awning. This can vary greatly, but you have different things to worry about if you're extremely tall or Eco-friendly polyester yarn very short. The cover itself should be made out of the most durable material available since it's subject to water, sun, dirt, wind, and mildew. While there's nothing wrong with a sprayed on finish, nothing short of anodizing can come close to the protection and coverage of electrostatic powder coating. Make sure to discuss pitch and projection, that is how far the awning will "stick out" from your house, and at what angle it will drop. Acrylic fabric is almost totally resistant to mildew and any form of rot. And speaking of the supporting structure, you want to look for all parts to be made out of aluminum, and finished with a powder coating. .If you're thinking about purchasing a retractable awning, the first thing you should do is educate yourself on what's available, and what industry terms are used to describe various features and options. You don't want your awning to look dulled and grimy the first year that you have it out after a winter-long storage. Retractable awnings are sometimes referred to as lateral arm awnings, a term derived from the support arms that run from the front of the structure diagonally down to the base of the supporting structure. This is in contrast to material that is only surface dyed or colored with a spray treating process. And while the best used to mean marine-grade treated canvas, in today's market it means an acrylic fiber that it dyed all the way through.