As a metal roof contractor, we are often asked whether metal roofing systems have to be grounded to mitigate the risk of lightning strikes. In today’s post, Gulf Coast Roofing sheds light on this issue.
Metal Roofs and Lightning
Contrary to what many think, the material of a structure is not what attracts lightning: it’s the electrical resistance, which, in most cases, happens to be the tallest grounded structure in any given area. In a typical residential area, this could be a tall tree or a church tower.
If your home happens to be the tallest structure in a wide area—therefore more likely to get hit by lightning—having a metal roof will actually give you more protection than any other type of roofing system, even a flat roof with a lightning rod installed on it. Metal’s natural conductivity helps disperse an electrical charge more efficiently, which helps minimize the damage caused by a lightning strike.
Factors That May Require Grounding the Roof
Metal roofs generally do not require grounding, and it’s not a requirement in international building codes. However, local building codes, particularly in areas where lightning storms strike often, may require you to have your metal roof grounded due to one or more of the following factors:
- Topography — Areas with varying topographical features like hills and flatlands are at a higher risk of lightning strike.
- Proximity to a Tall Structure — If your home is located close to a natural or man-made tall structure, it is at less risk of a lightning strike. Grounding the roof may help reduce the risk of secondary lightning strikes.
- Frequency — Homes located in areas that are prone to thunderstorms may be required to have grounded roofs.