24 dec 2012 02 45 pm.
Optimum roof overhang.
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.
The optimum depth varies with the latitude and the type of climate.
Roof overhangs a roof overhang is a simple architectural feature which can be used on the south side of the house to block direct sunlight in summer without reducing the available sunlight in winter.
Jonr senior member posts 5341.
An important component of passive solar design is calculating building openings doors and windows and roof overhangs.
Oversized overhangs can increase the risk of roof or truss uplift.
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.
Doing so keeps basements and crawlspaces dry and it also helps to.
How roof overhangs work.
For instance several features of a window will influence gain of solar heat and shade.
Figure 2 illustrates how this is possible.
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.
Overhangs are most effective for south facing elements in the northern hemisphere and at midday.
But are they really necessary.
Borst engineering construction llc competence integrity and professionalism are integral to all that we do.
Roof and overhang systems should be designed to resist wind uplift especially in hurricane prone regions.
Roof overhangs at the eaves and rakes protect the walls below from rain and sun.
Roof construction and materials considerations roof decking.
For high wind resistance use 7 16 inch or 19 32 inch plywood or osb roof decking attached with nails not staples.
There isn t general rules to size an 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 might look relatively routine but there is a lot of design thinking that goes into creating the optimal dimensions for each one.
180tan 10 in order to estimate the radiation received by windows with overhangs the beam diffuse and reflected com ponents of irradiance must be estimated as functions of time and day of the year.
They are essential for framing and shading windows reducing splashback and getting rain to fall far enough away from the foundation.
Borst passive solar roof overhang design calculator.
Geometry of overhang separated from top of window.
