Is a Roof Overhang the Leading Edge of the House?

Roof Overhangs

• All houses other than those with flat roofs have a roof overhang. Correctly sized roof overhangs provide two major advantages for practical purposes. They protect the dwelling from moisture damage from rain and snow, as well as shielding the effects of the hot sun in summer. Roof overhangs also provide aesthetic and architectural benefits, depending upon the style and type of roof. Roof overhangs over windows and entryways also guard window frames and doors from excessive moisture.

Overhang Size

• By allowing water collecting on the roof to fall to the ground beyond the dwelling's walls, a roof overhang protects the house's siding in addition to windows and doors. If the house has roof gutters to collect water runoff, the overhang still protects the building from rain blowing into it. Barbara J. Griffin, professor emeritus at South Carolina's Clemson University, recommends an overhang of three feet on the southern side of a one-story house to best control heat loss and gain from the effect of the sun, depending on the season of the year. A house with two or more stories must use somewhat larger overhangs to achieve the same effect.

Rooftop Safety

• Construction workers use several methods to ensure safety while working on the roof when an overhang is the leading edge. These include temporary guardrails or parapets that surround the working area, or a fall restraining system. This system combines an anchor point and a self-retracting lanyard that does not permit the worker to fall. The worker cannot reach an unprotected leading edge when using the fall restraining system. Some workers may use a personal fall arrest arrangement, a combination of an anchor point and either a lifeline with grab handles or a lanyard.

Other Overhang Benefits

• Properly placed overhangs can prevent excessive sun exposure to furniture and carpeting within the house. The need for overall exterior house maintenance lessens with correctly installed overhangs. The larger the overhang, the greater the moisture protection for the house, but the location's climate is also a determining factor for overhang size. Houses in rainy climates, such as the Pacific Northwest, especially benefit from larger roof overhangs.