Minimum Flat Roof Overhang

Figure r804 3 2 1 2 gable endwall overhang.

Minimum flat roof overhang.

Roof overhangs are the amount that the roof hangs over the top of the siding in residential home construction. We are building the roof and want to create an overhang that acts as a bit of a canopy above a bi fold door to shield it a bit from rain. Weather and not properly protected by a roof eave or similar covering table r802 11 required strength of truss or rafter connections to resist wind uplift forcesa b c e f pounds per connection r804 3 2 1 1 eave overhang. This is a compromise you will have to think about the larger the overhang the more pressure your roof will have to withstand.

In general roof overhangs offer an effective solution for how to protect windows doors and entryways. The length of the overhang depends primarily on the climate. The siding underneath the overhang is known as the soffit. Highly recommend either checking out the program martin linked to or a program like sketchup so that window size and placement can be modelled holistically with overhang design.

The roof on the house i m building is a dutch gable essentially a hip roof with gables that peek out at each end of the ridge with a 6 12 pitch and 32 overhangs. Does anyone know what the maximum overhang can be for a flat roof construction depending on joist size. A typical metal roof overhang may be 2 to 4 inches or even less. The minimum pitch for a roof is 1 4 12 which translates to 1 4 inch rise to 12 inches of run.

Some slight overhang is recommended in conjunction with a drip edge flashing to prevent water from getting under the roofing and onto underlying wood. Metal is usually installed on rafters or strip sheathing rather than the solid decking used under other materials. The ibc table 1505 1 lists the minimum requirements for roof covering fire resistance classifications a b or c for all types of. If the roof overhang is not big enough then the only way to protect these windows doors and entryways is by recessing them into the thick exterior wall or by installing special casing and flashing for each door or entryway.

However you can only use this pitch with built up roofing or specialized synthetic roofing. Overhangs are common in most house designs providing protection against both wind and rain. Eave overhangs shall not exceed 24 inches 610 mm measured horizontally. When required testing is in accordance with astm e108 or ul 790.

The larger the overhang the more upward lift will be created on the roof.