Outdoor area rugs are made with plastic, bamboo and other grasses -- or polypropylene. The latter is the most durable and flexible material. It can be woven to look like wool, but unlike wool, it is completely washable. Water runs off of this material, which means it holds its shape well. In addition, polypropylene can be dyed in any color. Some outdoor area rugs are made with a combination of these materials. Seagrass or bamboo rugs, for example, may be backed with polypropylene.
Outdoor area rugs are usually treated with chemicals to inhibit mold and mildew growth. This is because outdoor rugs will get wet, and if they are consistently moist, mold and mildew will grow on them. Even rugs that are chemically treated may still develop mold or mildew if they are continually wet. For that reason, set your rug out to dry in the sun if it gets soaked after a rainstorm. Or hang it from a clothesline, but do not drape it over the clothesline, as this can cause it to crease. Instead, hang it from an edge with clothespins.
Outdoor area rugs come in all shapes and sizes, from small, round balcony rugs to large pavilion or gazebo rugs. Some are made for specific purposes, like outdoor rugs that are often used in childcare centers or preschools. These have educational patterns on them, such as shapes or the alphabet. Or they have patterns designed for play printed on them, such as a hopscotch or tic-tac-toe. Most outdoor rugs are casually comfortable, but some have formal designs equaling what you would see in an Oriental rug.
If you are using your outdoor area rug to anchor a furniture grouping, measure the perimeter of the grouping, and then subtract 24 inches from both the length and the width. This will allow you to set your furniture partially on and off the rug. You want the furniture to anchor the rug to the surface. If you are using the area rug to cover up a space, simply measure the perimeter of the space and choose a rug with those exact or similar measurements.
Although outdoor area rugs are made to be durable, it's still a good idea to bring them indoors during inclement weather. Snow and freezing temperatures will greatly reduce the appearance and effectiveness of outdoor rugs. Roll them up rather than hanging them or folding them, as this will prevent cracks and creases from developing.