Awning
It is typically composed of canvas woven of acrylic, cotton or polyester yarn, or vinyl laminated to polyester fabric that is stretched tightly over a light structure of aluminium, iron or steel, possibly wood or transparent material (used to cover solar thermal panels in the summer, but that must allow as much light as possible in the winter).
In commercial buildings, an awning is often painted with information as to the name, business, and address, thus acting as a sign or billboard as well as providing shade, breaking strong winds, and protecting from rain or snow.
In areas with wintry weather, most awnings do not have to be taken down at the end of the summer – they can remain retracted against the building all winter long, or be designed and built for those conditions.
A Roman poet Lucretius, in 50 BC, said "Linen-awning, stretched, over mighty theatres, gives forth at times, a cracking roar, when much 'tis beaten about, betwixt the poles and cross-beams".
Among the most significant awnings in the ancient world was the velarium, the massive complex of retractable shade structures that could be deployed above the seating areas of the Roman Colosseum.
At that time they consisted of timber or cast iron posts set along the sidewalk edge and linked by a front cross bar.
To lend support to larger installations, angled rafters linked the front cross bar to the building facade.
On ornate examples, metal posts were adorned with filigree and the tops decorated with spear ends, balls or other embellishments.
On overcast days or when rain did not threaten, the covering was often rolled up against the building facade; during the winter months proper maintenance called for the removal and storage of awnings.
Canvas duck was the predominant awning fabric, a strong, closely woven cotton cloth used for centuries to make tents and sails.
Iron plumbing pipe, which was quickly adapted for awning frames, became widely available and affordable as a result of mid-century industrialization.
In case of sudden storms, owners could quickly retract the awning against the building wall where it was protected from wind gusts.
If poorly designed or badly placed, the retracted fabric could obscure part of the window or door opening, and even if out of the way an imperfectly folded awning presented an unkempt appearance.
When passing showers threaten, or when the sun gets hot, they or the home automation system unroll the awning for near-instant protection and shade.
Because awnings prevent the sun from shining through windows and sliding glass doors, they can keep temperatures inside cooler as well, which saves on air-conditioning costs.
These arms provide extra support and stability which some owners prefer in windy areas, and increase the awning's versatility by making the attachment of certain accessories available.
Modern awnings are rated for wind tolerance based on width, length, number of supporting arms, and material.
Modern awning design incorporates urethane compression joints, steel support structures, and wind sensors.
Among the many benefits of these awnings are cooler temperatures inside the home, shade for your patio, extending the life of furniture and window treatments.
Most of these systems are water-proof as compared to water-resistant (lateral arm awnings) and therefore allow no water penetration through the fabric "roof" section.
Another advantage of retractable patio cover systems is that they can be enclosed on the front and sides using solar shade screens.
Commonly used to shade a window, with a roller tube at the top, spring-loaded side arms, and a motor, crank or tape-pull operator.
Drop Arm Awnings without sides come with roller tubes at the top and are available with motors and wind sensors for automatic retraction.
