Wind Resistance

© 2003 Door & Access Systems
Publish Date: Spring 2003
Author: Tom Wadsworth
Page 64


What Dealers Should Know
Part II

By Joe Hetzel, DASMA Technical Director

With the widespread adoption of the International Building Code, door dealers can expect more code officials to be checking garage door for compliance with wind resistance requirements. That means dealers need to be informed about this importance characteristic of garage doors.

To determine a garage door’s wind load requirements, here’s what you need to know.

· The Garage Door Size. This one’s easy. Give these measurements (in width by height) to building officials, contractors, and design professionals.

· The Garage Door’s Distance from a Building Corner. Specifically, know the distance from the corner of a building to the garage door jamb closest to that corner. DASMA wind load guides assume a two-foot distance. If the least dimension of the building is greater than 40 feet, a design professional may be needed.

· The Building Height. Use the mean roof height, which is the average of two measurements: (1) the distance from grade to the eaves and (2) the distance from grade to the roof peak. If the mean roof height is greater than 25 feet, you might need a design professional.

· The Building Use. If the building is an “essential” use structure, wind loads must be increased by 15 percent. “Essential” means that the building would be needed in emergencies.

· Roof Pitch. A roof with a slope less than 10 degrees (1:6 slope or less; known as a “low-slope” roof) is considered a “commercial” structure. Garage door wind loads are approximately 10 percent less for structures with low-slope roofs.

DASMA’s garage door wind load guides consider the above factors and present simplified tables to help you quickly determine wind load requirements. You can find the DASMA wind load guides in Technical Data Sheet (TDS) 155, in the Commercial & Residential Garage Door Division Publications link at All DASMA Technical Data Sheets are free.