Minimum Flat Roof Overhang

In general roof overhangs offer an effective solution for how to protect windows doors and entryways.

Minimum flat roof overhang.

Metal is usually installed on rafters or strip sheathing rather than the solid decking used under other materials. The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process. The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures. 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.

This is a compromise you will have to think about the larger the overhang the more pressure your roof will have to withstand. Two feet is the general maximum length for a typical roof overhang. Minimum roof snow load p m i s p g p g 20 psf p m 20 i s p g 20 psf the 20 psf value is our estimate of the maximum size of a single heavy snow storm 5 minimum roof snow load after the single heavy snow storm eventually the wind blows thermal effects have time to act and we then get p s on the roof. A typical metal roof overhang may be 2 to 4 inches or even less.

This will protect a roof from most types of damage. Some slight overhang is recommended in conjunction with a drip edge flashing to prevent water from getting under the roofing and onto underlying wood. Of course it is common in the philippines to build the overhangs larger so to keep the sun off the concrete walls. Roof overhangs can extend farther than 2 feet but beyond this length they begin to lose structural integrity and require external supports.

Determine the minimum slope of the roof based on the roofing material.