Eave, balcony, porch and verandah projections are measured to the outside edge of the feature including any fixed attachment such as a gutter. For example, if your roofing truss overhangs by 450mm and you have a standard 25mm fascia and 125mm gutter, then select 600mm projection. Measure projection to the face of the wall in which the window is located.
Note: Shading with an external permanent projection must extend horizontally on both sides of the window or glazed door for a distance not less than the projection (P).
A shading projection that is less than 500mm above the head (e.g. eave) will typically provide reasonable shading whereas a projection that is higher (e.g. skillion roof) will allow more sun to hit the window and will be less effective.
The BASIX DIY method will account for half of the projection specified if the leading edge of each eave, pergola, verandah, balcony or awning is between 500mm and 1500mm above the head of the window or glazed door. DIY method will not give credit for projections greater than 1500mm above the window head.