In What Direction Should a Metal Roof Be Applied if High Winds are a Consideration?

Panel Direction

• Standard metal roofing comes in long panels that extend from the roof ridge to the bottom edge of the roof, with the ridges or corrugations running from top to bottom. This vertical configuration directs rainwater down and off the roof.

Lapping the Panels

• Metal roofing panels lap at the edges. If you live in a windy area, it’s essential to lap the panels in an order or direction that submits to the prevailing wind. For example, if the prevailing winds in your community are from the west, you would install the first metal roof panel on the eastern-most edge of the roof, and the next panel would overlap the first one. This reduces the risk of high winds catching the edges of the panels.

A Strong Base

• Many types of metal roofing panels install over purlins, which are horizontal boards attached to the roof rafters or to roof decking. When high winds are a concern, installing the purlins closer together allows the roofer to insert more screws through the metal panels. Metal roofing comes with installation specs that usually stipulate maximum purlin spacing, but you are free to install purlins closer together. For example, if the roofing manufacturer stipulates a maximum purlin spacing of 24 inches, you can install purlins 16 inches apart to provide a more substantial base for the metal panels.

Finishing Touches and Considerations

• High winds are dangerous to metal roofs when the roof has exposed edges. By installing a metal wrap-type fascia and gable trim along the edges of a roof, the wind is less likely to catch the panels and tear them off. In addition, the heavier the gauge of the metal, the more likely it will be to resist wind damage.