Retractable awnings use a flexible aluminum or canvas cover along with a manual or hand crank to store the awning in a cassette when it is not in use. When the owner wants protection from the sun or rain, he extends the awning using the crank.
The most common types of retractable awnings use articulated arms. These support arms open in stages, using a spring-loaded system to extend the cover. Awnings with gas-filled telescope arms are the second most common type of unit. These units require more maintenance, due to potential gas leaks; they are generally smaller than the articulated arm devices.
Manual awnings have a crank that operates a gear system to extend or retract the unit. Owners can usually remove the crank when it's not in use. Some crank-type awnings with articulated arms fold back flat against the house for storage.
Motorized awnings operate with the push of a button. Most have a manual override in case of motor malfunction. Some have automatic sensors that retract the awning when it needs protection. Motorized awnings generally require more maintenance than manual ones do.
To protect retractable awnings, retract them when they are not in use. While the awnings have solar protection and waterproofing, they may crack or tear with extended exposure to the elements.