Patio covers are used to protect the furnishings, but to get the best of them it is essential that they are vented properly. Free flow of air is necessary to prevent damage to the furniture. If there is insufficient air flow to the patio furniture the mold and mildew build up may cause irreparable damage. Vinyl patio covers that are of high quality will be double stitched and also protected from the harmful UV rays of the sun. Also, if a strap and buckle system is used for the covering it will help prevent the covering from wind and from being blown away. Covers that have water resistant coating must have binding over the seams, lest rain water get inside.