Shade is
one of the most effective ways to reduce the risk of exposure to ultraviolet
rays from the sun. Shade alone can reduce overall exposure to UV radiation by
about 75%. (www.SunSmart.com.au The Cancer Council of Victoria, Australia, 2008)
Correct type of shade with the use of protective clothing, hats, sunglasses and
sunscreen can provide the maximum sun protection. Shade can also provide a more
comfortable environment by reducing heat and glare from the sun, especially
during summers.
Shade options include:
Trees
Portable structures such as umbrellas,
tents and shade sails
Permanent built structures such as gazebos,
pavilions, awnings, patio roofs and pergolas
No one
shade design will meet all needs and suits all situations. Careful planning
ensures that the best type of shade is to be used. Planning should include
assessment of:
where
shade is needed
when
shade is needed
duration of expected use, permanent or temporary
what
activities will take place under the shade, i.e. the size of shade
funds
available for providing shade
Built shade structures – portable
and permanent
Portable structures are readily available off the
shelf and easy to set up, take down and stored. They are a quick and
cost-effective way to add shade to a space that only needs shade occasionally or
for a short time, but they may not be effective in protection from indirect UV
radiation reflected off surfaces such as sand and concrete. Portable structures
include umbrellas and tents.
Installed adjustable and/or demountable structures such as retractable awnings
to the side of your house or shade sails are practical and flexible, allowing
change of shade in relation to the sun at that time of day and at different
times of the year.
Permanent structures, which provide a permanent shade solution, are built
structures of different shapes and sizes to accommodate more people, typically
made up of a roof and supporting posts. They are generally more expensive, but
are usually sturdier and more durable, and can withstand harsh weather
conditions.
Examples of permanent shade structures include pavilions, gazebos or pergolas, which are
attractive, practical and can be used in all seasons. Most important of all, it
can minimize the impact of indirect UV radiation.
Considerations for built shade structures
Other than the cost and ease of installation, considerations for built shade
structures should include:
Common shading materials for built shade
structures are timber shingles, polycarbonate and fibreglass sheeting, knitted
polythene or woven PVC shade cloth, canvas or other tightly woven cloths.
When
choosing shading material, it is important that the shading material have a UPF (ultraviolet protection factor) of 15-50+, i.e. allowing only 6 to 2% of
the UV radiation to pass through or at least a 94% UV radiation protection.
UPF 15-24 (94 - 95.9%) Good
UPF 25-39 (96 - 97.4%) Very Good
UPF 40-50+ (97.5 - 98%+) Excellent
Two factors that can affect the UPF of fabric
are weave and colour. Fabrics that have a tighter weave will block more UV
radiation. Darker colours absorb more UV radiation and therefore provide
better sun protection.
Textile or coated fabric (canvas) can provide up to 99% UV radiation
protection or a UPF of 50, but is susceptible to breakdown due to UV radiation
exposure, therefore it often has a shorter life span than shade cloth.
Shade cloth gives only medium protection of about 90% against UV radiation.
Double knits may give higher protection. It is also porous and may let water
through.
Be
aware of safety concerns of the shade structure
Does
it conform to current building codes?
Are
the support systems such as posts visible?
Are
there any ropes that may pose a trip hazard?
Is it
made of non-toxic materials if used for playgrounds and school areas?
Can
water run off its roof to avoid water-related problems later?
Are
steps taken to minimize vandalism by selecting sturdy materials, having
covers high away from reach, keeping the shade structure away from fences,
walls or trees that can be climbed, etc.?
Other
factors to consider are:
maintenance requirements
waterproofing qualities
environmental consequences
wind
resistance and ability to withstand the winter
Planning
for Shade
No one
shade design will meet all needs and suits all situations. Careful planning
ensures that the best type of shade is to be used. Planning should include
assessment of:
Permanent structures, which provide a permanent shade solution, are built
structures of different shapes and sizes to accommodate more people, typically
made up of a roof and supporting posts. They are generally more expensive, but
are usually sturdier and more durable, and can withstand harsh weather
conditions.