Fixed shading with battens
Pergolas with battens must have battens parallel to the window or glazed door to qualify as a shading device. Pergolas with only the framing or members perpendicular to the window or glazed door do not provide sufficient shading to be considered. Battens that are perpendicular to the window or glazed door can only be counted if they are also providing shading to an adjacent window or glazed door such as in a courtyard.
The batten spacing (that is, the distance between battens) must not exceed the batten height.
For a pergola with fixed battens, measure the projection (P) from the window to the leading edge, that is, the last batten in the series.
For a pergola with fixed battens, measure the height (G) from the head of the window to the leading edge, that is to the top of the batten series.
For a pergola with fixed battens, the spacing between battens must not exceed the thickness of the battens.
Fixed shading with sheeting
Pergolas with polycarbonate or fibreglass sheeting or other similar material must have a shading coefficient of less than 0.35. The lower the shading coefficient the better the shading. Manufacturers can provide the shading coefficient of their product range. Generally clear sheeting will not have a shading coefficient less than 0.35 – a tinted sheet will need to be used for the pergola to qualify as a shading device.
If you want to have a pergola with clear sheeting or tinted sheet with a shading coefficient of greater than 0.35 you must nominate ‘no shading’ for that window. However, you can still build the pergola.
Adjustable Shading
Select pergola with adjustable shading if you have adjustable blades or removable shade cloth. Adjustable blades must be capable of blocking the sun in plan view, i.e. when viewed from above – most systems are designed this way.
Removable shade cloth must have a shade ratio of at least 80% to be considered. Most manufacturers provide their shading products with the shade ratio specified.
For a pergola with adjustable blades, the blades must be capable of completely blocking sunlight when it is directly overhead.Awnings