Optimum Roof Overhang

There isn t general rules to size an overhang.

Optimum roof overhang.

You can use the free software sketchup to draw the house and it will draw sun shadows for any date time at your location. Roof overhangs at the eaves and rakes protect the walls below from rain and sun. Roof and overhang systems should be designed to resist wind uplift especially in hurricane prone regions. Overhangs are most effective for south facing elements in the northern hemisphere and at midday.

But are they really necessary. Roof overhangs should be no more than 2 feet wide. Oversized overhangs can increase the risk of roof or truss uplift. Roof overhangs might look relatively routine but there is a lot of design thinking that goes into creating the optimal dimensions for each one.

Borst engineering construction llc competence integrity and professionalism are integral to all that we do. How roof overhangs work. The optimum depth varies with the latitude and the type of climate. Borst passive solar roof overhang design calculator.

Doing so keeps basements and crawlspaces dry and it also helps to. For high wind resistance use 7 16 inch or 19 32 inch plywood or osb roof decking attached with nails not staples. An important component of passive solar design is calculating building openings doors and windows and roof overhangs. Those larger than 2 feet wide have to withstand very high uplift so they should be engineered.

Optimum overhang dimensions for energy saving 295 sun fig. If the building element bears more than about 30 off true south the effectiveness of an overhang as with any solar feature begins to decrease significantly. Jonr senior member posts 5341. The size of the window width and height and the window s relationship to the roof the space above the window influences the direct.

Geometry of overhang separated from top of window. They are essential for framing and shading windows reducing splashback and getting rain to fall far enough away from the foundation. For instance several features of a window will influence gain of solar heat and shade. Roof construction and materials considerations roof decking.

With composite siding such as boral s truexterior siding over a ventilated rain screen and with properly executed flashing at the windows and doors the walls on the fhb house will be able to handle rain just fine. Because the sun travels a higher path in the sky in the summer than in winter the overhang blocks. 24 dec 2012 02 45 pm.