Roof Uplift Requirements

Because fm approvals requires a 2 1 safety factor roofs with field of roof uplift forces of 30 pounds per square foot are the maximum for 1 60 ratings and 37 5 pounds per square foot are the maximum for 1 75 ratings etc.

Roof uplift requirements.

Another modification provided in the april 2009 fm 1 52 is to increase the allowable deflection for metal decks. As a result most nailing patterns in high wind areas require 8d nails at a maximum of 6 inch spacing along all framing members. To ensure a correctly built metal roof there are a variety of wind uplift tests manufacturers use to test their metal panel systems. Decra roofs also have the resilience and durability to withstand the most challenging wind conditions even in florida s.

Wind uplift is a near constant force on roofs with wind movement from zero to over 170 mph. These tests are necessary to understand how a metal roof system can withstand both external and internal pressures which is important when trying to meet design and performance requirements in projects. These roof deck types are steel minimum 22 gauge wood cementitious wood fiber plank and structural concrete minimum 2 500 psi. Let s assume that the calculations for our building require a roof that can withstand 23 pounds per square foot of uplift force in the field of the roof.

Testing of panel uplift resistance following hurricane andrew led to significant changes in prescriptive roof sheathing nailing requirements throughout much of the u s.