A shade sail is a patio or deck covering made from durable outdoor fabric that provides protection from the sun. Shade sails are installed by stretching the fabric and using tension to affix the corners of the shade to mounting points (like a pergola, post, tree or wall). Shade sails are considered a more affordable and versatile alternative to a hard-structure roof. Shade sails come in various shapes, sizes and colors to fit any style backyard.

Of course the main benefit of rectractable shade sail is sun protection. Most shade sails block between 90 to 95 percent of UV rays. There are some variations in UV absorption depending on the shade material’s weight color and the tightness of the weave, but the differences are typically less than five percent. But if you want maximum sun protection, know that heavier fabric, a tighter weave and darker colors generally block the most UV rays.

You also might want your shade sail to block rain. Triangle sun shade sail are water resistant but not waterproof. A light sprinkle will roll off the shade, so it’s important to install it at an angle. In a heavy downpour, water will drip through the shade because it’s made from breathable woven fabric, which allows air to pass through and keep the shaded area cool. If you want full rain protection, look for a shade specifically categorized as waterproof.

Skin cancer is among the most common cancers in light-skinned populations worldwide, and melanoma incidence has increased beyond that expected because of population growth and aging.1 There will be an estimated 87 110 cases of melanoma in the United States2 and 13 941 cases of melanoma in Australia3 in 2017. The primary risk factor for skin cancer, and the most avoidable, is exposure to solar ultraviolet (UV) radiation.4

To prevent skin cancer, individuals are advised to minimize UV exposure by staying in the shade.2,5 Permanent purpose-built shade can provide known amounts of reduction of UV exposure.6 Shade is part of the built environment,7 which according to social-ecological models8 can have direct effects on behaviors (e.g., increasing individuals shaded, providing a visible cue for sun protection, and enabling access to protection without planning9,10). Shade may attract high-risk individuals with unfavorable attitudes toward sun safety to use shade for maintaining comfortable body temperatures.11

Identifying environmental features amenable to change holds promise for improving population health7; however, evidence is limited mainly to cross-sectional or quasi-experimental designs with scant prospective trials.12 The prevalence of, trends in,13,14 and demographic and attitudinal correlates of shade use, along with the association of shade with temperature and sunburn incidence, have been reported.15–17 A study in Melbourne, Australia, secondary schools remains the only prospective randomized trial of purpose-built shade for sun protection9,11; it found that students used rather than avoided shade.11

The ability to improve sun protection by introducing shade needs to be tested in other locations and with adults. Public parks are popular for outdoor recreation, and shade is a desirable feature in parks.10 The present trial prospectively tested the effect of purpose-built shade on use of passive recreation areas (PRAs) in public parks (i.e., areas used for sitting or standing while socializing, preparing or eating a meal, watching or coaching sports, watching a concert, taking a class, or waiting, or areas where people stroll for sightseeing or while observing outdoor displays). We hypothesized that the introduction of triangle patio shade sail over PRAs would increase the use of the PRAs by park visitors compared with unshaded control PRAs (hypothesis 1). Social-ecological models suggest that built environmental features influence health risks through their interplay with the social environment. Australia has a longer history of comprehensive efforts to prevent skin cancer than the United States.18,19 Accordingly, stronger norms for sun safety in Australia than in the United States are expected, so we hypothesized that the increase in use of PRAs at shaded PRAs would be larger in Melbourne, Australia than in Denver, Colorado (hypothesis 2).