Roof Overhang Shading

Using sketchup i just fiddled around with the overhang width window size and vertical placement until i got the desired shading effect.

Roof overhang shading.

Overhang depth for solar heat gains and shade. For hot dry climates with some heating requirements gradually increase the overhang up to 50 of height full shading. The roof overhang does not extend far enough. In passive solar home design exterior roof overhangs provide a practical method for shading building elements such as windows doors and walls.

Overhangs are most effective for south facing elements in the northern hemisphere and at midday. Because the sun travels different paths across the sky in the winter low and summer high time an overhang can be constructed to utilize and manipulate the heat energy from the sun. That might be desirable during winter months but very uncomfortable during hot summer months. There are two common problems encountered with roof overhangs.

The shade is in 1 increments. You may use wide overhangs and verandas in hot climates without a cold season and in hot wet climates with high levels of rainfall but oversized overhangs in other. For example if the roof s overhang does not shade the window during the hottest hours of the day direct and reflected sun light will heat the interior. An overhang or some sort of solar control or solar shading is a crucial element in passive solar design because it blocks the sun s heat energy when it is not desired.

A value of 73 for example indicates that the overhang is shading about 27 of the window area and 73 of the window is in the sun. For hot humid climates and hot dry climates with no heating requirements shade the whole building at all times with eaves overhangs of 50 of height from floor level to both north and south where possible and use planting or adjoining buildings where it is not possible. The roof overhang is too wide. How roof overhangs or other window overhangs work to control heat and solar gain.

No i just made the overhangs wide enough to provide the extra shade. In the first case the overhang is simply too big for the home. The sun is in 1 increments. This leads to a situation where there is an excess amount of shade and the exterior of the home appears dark and gloomy.