A shade sail is similar to a boat’s sail except it’s attached to a roof or an outdoor structure to form a canopy. Tilted or twisted overhead, shade sails offer protection from the sun on hot summer days.

Constructed from UV-resistant, high-density polyethylene fabric, these flexible membranes come in a range of colors, shapes, and sizes.

What to Consider When Choosing the Best Shade Sail

If you’re looking for a way to add shade to your outdoor space, a shade sail may be the best solution for you and your home. These beautiful backyard canopies block out harmful UV rays while adding elegance to your outdoor area. Here are a few things to consider when shopping for a quality shade sail.

Most shade sails are made of tightly woven, high-density polyethylene fabric (HDPE), polyvinyl chloride (PVC), or nylon fabric. Shade sails are installed by stretching the fabric and using tension to attach the corners of the shade to a stable structure (such as a roof, post, wall, or tree) via stainless steel D-rings and turnbuckles (stainless steel devices to adjust tension). If installed correctly, shade sails should provide a perfectly taut canopy.

Shade sails come in a variety of shapes and styles but are typically sold in three shapes: triangle, square, and rectangle. Of the three, the triangular sail is the most popular. This is because square sun shade sails tend to bow in the middle, due to a buildup of water. (They’re also not as elegant as their three-pointed counterpart.) Triangular sails are perfect for both small and large areas and can be layered for a more dramatic effect.

All shade sails should offer maximum sun-blocking power. Look for fabrics with 90 percent UPF (ultraviolet protection factor) or higher. Like sunscreen, sun shade sails are designed to protect your skin and eyes from the sun’s harmful rays. Beyond UV protection, shade sails are built to withstand varied weather conditions, especially rain and wind. If you live in an area with harsh winters, you may want to stow your shade sail until spring.

The benefit of HDPE material is its stretchy breathability, allowing wind and rain to pass by without harming the shade itself. Although HDPE sails can withstand heat, wind, and rain, they’re not equipped to protect you during a storm. If you know there’ll be a strong thunderstorm or hurricane coming through, you should take your shade sails down to prevent them from getting damaged.

PVC is less breathable, but it creates the perfect waterproof shade sails. This is helpful if you want to use your shade sail during summer showers. In this case, you will need to position your sail at a slant, so it doesn’t collect water (leading to a heavy, sagging canopy).

Before settling on a sun shade sail, be sure to measure your outdoor space correctly. Leave a perimeter (1.5 to 2 feet) around the shaded area for the turnbuckles, which will attach the sail to your roof or other elevated structure. Remember: Shade sails are measured from the edge of their D-rings, which are fitted to each corner for hanging purposes. In most cases, you’ll need to purchase a hardware kit intended for either a triangle or rectangle sail.

Make sure to attach the hardware to a structurally sound point, like your home’s roof. Both rectangle and triangle shade sails are often installed at a slant to prevent rainwater from pooling. However, many residential shade sails are made with HDPE material, allowing water to pass through.

In this case, it is also possible to position them flat or twisted into a hyperbolic paraboloid (also known as a hypar twist). This three-dimensional shape is achieved by attaching one or two corners higher than the other corners. The benefit of a twist is a greater distribution of surface tension and a stronger shade sail overall. The end result is also beautiful aesthetically.

For another bold architectural effect, try installing overlapping shade sails. This extends your shady area without putting too much tension onto a single, big sail. When installing overlapping sails, make sure you leave a minimum of 12 inches between them. If not, wind and weather conditions can cause the sails to rub against each other, damaging the fabric over time.