For kayaks, it's best to keep them stored away from the outdoor elements. Sunlight, moisture, and extremely cold or hot temperatures can damage the material of the kayak by cracking, warping, and fading. Renting a climate-controlled unit will prevent any of these damages from happening to your kayak over time.
Wall-Mounted Rack. You'll need plenty of wall space for this storage solution, but it's a great way to store multiple kayaks in your garage or self storage without taking up any floor space.
Overhead Suspension System.
Wall-Mounted Sling Set.