At what wind speed will a roof come off?

At what wind speed a roof will come off depends on many factors including shingle type, age, installation quality, roof shape, and whether shingles have properly sealed. Standard 3-tab shingles rated for 60 mph may start losing tabs in sustained winds of 50 to 60 mph if they are old or poorly sealed. Architectural shingles are typically rated for 110 to 130 mph with proper 4 to 6 nail installation and sealed tabs, so they should resist blow-off up to those speeds when new and properly installed. However, real-world failure often occurs at lower speeds due to factors like cold weather installation without hand sealing, high nailing, overdriven nails, or aged sealant that has lost strength after 15 years. Once one shingle lifts, wind can get underneath and create a peeling effect that removes large sections at speeds lower than rated. For complete roof system failure where decking comes off, winds generally need to be much higher, typically 110 to 150 mph as seen in hurricanes or tornadoes, especially if the roof to wall connections are weak. Gable roofs are more vulnerable than hip roofs. Building codes in hurricane zones require 6 nails per shingle and enhanced sealing to achieve 130 to 150 mph resistance. So while a well-installed new architectural roof should stay intact in 90 mph gusts, an old or poorly installed roof can lose shingles in 50 mph winds.