It’s summer. Time to think about kicking back in the shade in your back
yard. Whether you’re considering installing a shade sail, pergola, awning, or
even buying some deciduous trees, here’s what you need to know when choosing shading structures. Coverage Brian
Darnell, director of design and general contractor at Leap Adaptive in San
Diego who has designed a
variety of plans with shade-making overhangs like his Plan 484-6 shown here, tells clients to select a shading
device based on two key concerns, function and cost. “Function is almost always the first
priority,” Darnell says, which means deciding why you need shade and then providing effective coverage
where—and when—you need it. “Typically,
you want to be able to cover a seating area for six people, and/or a small
furniture grouping. An 8-foot dimension of shade is going to be minimal for a functional
gathering space, and 10 to 12 feet is preferred. If you’re simply providing
shading at a window system, then a 2 to 3-foot projection from your home can
provide a nice shading coefficient,” he says. It’s
also important to think about the height of your shade structure above the shaded
surface. Opinions on this point differ. “The higher you locate the cover, the less effective it becomes,”
Darnell explains, adding that the aspect of relative scale to the building also
needs to be considered. Darnell recommends a height of 8 to 10 feet for most
shade structures and 12 feet for a very large structure. Jeffrey Gordon Smith of Jeffrey Gordon Smith Landscape Architecture in
Los Osos, California, prefers higher ceilings outdoors. “I don’t think
people are as conscious about scale in outdoor spaces,” Smith says. “Most
people understand what an 8-foot ceiling is and are comfortable with indoor
spaces, but an 8-foot ceiling in an exterior space is fairly claustrophobic. When
I move to outdoor spaces, the ceilings, whether created by trees or structures,
should be higher."
An additional factor to consider is whether your view will
be framed—or cut off—by the height, width or depth of the shade structure.
Smith and Don Crenshaw, owner of Shade Sails.com LLC, both
recommend creating a 3-D model or string mock-up (or
asking a professional to do so) before installation so that you can get a feel
for what the final shade structure will look like before you build it. Cost “Someone may love an architectural sail type of
canopy, but these constructions are typically expensive, unless they’re smaller
scale and anchored to the existing building,” Darnell says. Smith adds that
shade sails can cost more than you think due to the necessary structures and
support materials, which can include poles and stanchions set into deep
footings and lag bolts set into the home. According to Crenshaw,
many housing communities now have strict building codes, and putting up a shade
sail can require hiring a contractor and pulling a permit, which can double or
triple the cost. Smith adds that retractable awnings are the most expensive
shading option and require the most troubleshooting. “On the other hand, a
simple timber trellis or pergola may fill your shading need nicely, and you can
build it yourself with simple tools and materials from your local hardware
store,” Darnell says. “Trees
are also fantastic passive shading elements when easily integrated into the
equation. They offer cooling shade, oxygen, kinetic energy and an almost
interactive environmental habitat with birds, insects, squirrels and other tree
dwellers.” Smith agrees, recommending deciduous trees that lose their leaves in
winter when you want more sun entering your home. Sun angle Calculating the sun angle is an important factor when shading a space in your
yard, Darnell says. This means thinking about how you will use your shaded
space during different seasons and how effective your shading device will be at
different times of year in relationship to the direction from which the
sunlight is coming (the azimuth angle).
(Image courtesy of Sustainable Buildings Industry Council (SBIC) and the Beyond Green™ Guidelines for High- Performance Homes via "Sun Control and Shading Devices" from the Whole Building Design Guide.) “The size
and shape of the shading device needs to take into account the purpose, sun
angle and effectiveness sought,” Darnell says. “Too many times we see little eyebrow
shading devices that do little or nothing to provide a solar shading
coefficient. If you’re going to provide shade, make it meaningful, not a
half-measure attempt to provide minimal protection.” A designer or landscape architect can easily
help you calculate the sun angle for your shade structure and yard. Materials In
general, Darnell recommends choosing
a metal and fabric shade structure. He personally prefers powder-coated
aluminum or medium-gauge steel with a tensioned Sunbrella® fabric
(Sunbrella fabric fibers are saturated with UV-stable pigments, and the fabrics
resist mold and mildew, can be easily cleaned with a bleach solution and are
breathable). ShadeSails.com LLC is another option (example below and at the top of this post). Crenshaw says that his
company’s
sails are constructed of high-density, knitted polyethylene fabric with UV
stabilizers and SolarFix®
thread (made of polytetrafluoroethylene [PTFE]
fiber), and some are also fire retardant (photo courtesy Shade Sail LLC). He adds that the edge curves of his
shade sails are designed in a specific shape that imparts equal tension into
the membrane to avoid the wrinkles and droopy middles that people experience
with some shade sail products. Coolaroo is
another well-known provider of shade sails and exterior sun shades that are made
of high-density, knitted polyethylene fabric. Environmental Factors Environmental
factors can have a profound impact on selecting a shading device or structure,
especially when in the presence of extreme conditions. For example, if you live
in a high-fire zone, Darnell says do notuse light timber structures that could create a
combustible bridging element (you don’t want a timber structure expanding the threat
of fire to your home when it’s near an area prone to wildfires). And if you’re located
near the sea, Darnell says that type 316 stainless steel is the least corrosive
metal you can use; any other metals will need to be powder coated or Kynar
painted and will still corrode over time. Darnell also suggests vinyl,
fiberglass, and acrylic as possible materials for your seaside shaded space, as
well as wood, although even teak needs to be finished and painted regularly to
protect it from the salt air. For those who opt for a shade sail, Crenshaw
recommends that, if you live in a climate subject to tropical storms, such as
Florida, you take it down during those storms. And, if you live in a climate
that gets snow in the winter, such as Colorado, take your shade sail down when
you winterize your yard and swimming pool because the knitted fabric may
stretch under the weight of the snow. Other Considerations Is your shade device is structurally sound? Can it be easily
adjusted? Smith
considers shade sails somewhat permanent structures, like deciduous trees.
While the fabric can be taken down and put away, the posts are usually
permanent. Crenshaw adds: “Shade sail posts are 4-inch or 6-inch pipe and are
15 feet tall or higher. People request movable posts but
they don’t work as well.” Crenshaw says too many
people order triangle shapes that are 2-D flat planes instead of thinking in
terms of 3-D forms like a potato chip (a hyperbolic paraboloid in math terms).
Not only are these 3-D shapes more visually intriguing, but a 3-D load on the
fabric is actually more sustainable in wind and doesn’t collect as much water. And
don’t forget to put your shade sail under enough tension so that it doesn’t move
in high winds and wear out faster.
