Shade Sails are made of high density polyethylene shade cloth that is especially manufactured with tensioned fabric structures in mind. The knit is made using monofilament and tape filler. The fabric is treated with a UV stabilizers to give it long life in direct sunlight. Depending on color, the average shade rating is approx. 90% and the UVR block is approx. 95%.
Custom and commercial sails are manufactured with a stainless steel cable double locked stitched into its perimeter. This cable terminates at a stainless steel ring located at each corner. These rings are then used to fasten the sail by either a shackle or turnbuckle to a hard point either on a post or existing structure. Each corner is further reinforced with extra layers of cloth and strapping to distribute forces. All stitching is performed using a locking stitch; outdoor “awning maker” thread is used throughout. The size of the stainless cable and rings as well as attachment hardware are engineered to be the appropriate size for each sail and application.
The perimeter of each sail has a catenary curve designed into it that controls the fabric tension in the center of the sail. Therefore, when tension is placed on the perimeter cable, the fabric will have uniform tension. They do not sag or flap in the wind.
Attachment hardware is all marine grade stainless steel and has locking mechanisms to assure that sails do not detach or come loose accidentally. Generally, one turnbuckle is used per sail, and the remaining corners are attached using “D” or “Twist” shackles of the appropriate size for the expected corner loading.
Sails can be attached to existing structures with a variety of common or custom made brackets and hardware. They can also be supported by their own columns made of either timber or steel pipe. We prefer to use schedule 40 galvanized steel pipe embedded in concrete footings. The dimensions of the pipe and the footings are engineered for each sail and its application depending on the size of the sail and the expected wind loading. The columns can then be powder coated or painted to help protect them and provide the desired color. If timber posts are used, then we generally use temporary power poles with a preservative added to the wood.
Depending on local building codes and engineer’s requirements we add either threaded rod or rebar to the footings or posts to tie the concrete and post together. In general, there is very little gravitational load, but uplift is the concern, and footings can be quite deep.