Understanding Wind Uplift: A Guide for Metal Sheet Roofing Systems
- Yuttapichai Ngotiat
- Sep 24
- 4 min read
Updated: Oct 1
When it comes to roofing, few forces are as unforgiving as the wind. Among the many design considerations for metal sheet roofing systems, wind uplift resistance stands as one of the most critical, especially in storm-prone or open-terrain environments.
In this blog post, we’ll break down what wind uplift is, why it matters, the factors that affect it, and how our TSS roofing systems are engineered to meet the highest performance standards.
What Is Wind Uplift?
Wind uplift refers to the upward pressure exerted by wind on a building’s roof system. This force can cause roof panels to detach or deform, especially if the roofing system isn’t adequately anchored or designed to distribute pressure. It’s not just strong gusts that are dangerous — even moderate, sustained winds over time can compromise poorly designed roofs
When wind flows over a building, it creates areas of high and low pressure. Negative pressure develops over the roof surface, pulling the materials upwards, like the lift under an airplane wing. If the roofing isn’t properly secured, this suction effect can literally peel the roof off
What Causes Wind Uplift?
Wind uplift is influenced by a combination of environmental and structural conditions. Here are the most important ones:
1. Windspeed in the Area
Naturally, the higher the windspeed, the greater the uplift pressure.
Local wind zone maps and codes help determine design requirements.
Group 1 V50 = 25 meters per second : TF = 1.0
Group 2 V50 = 27 meters per second : TF = 1.0
Group 3 V50 = 29 meters per second : TF = 1.0
Group 4A V50 = 25 meters per second : TF = 1.2
Group 4B V50 = 25meters per second : TF = 1.08
2. Surrounding Terrain / Surface Roughness
Open, flat, and unobstructed terrain (e.g., fields, coastal zones) create higher uplift forces.
Built-up urban areas with closely spaced buildings reduce wind speed and turbulence.
3. Building Enclosure Type
Enclosed buildings: doors/windows closed most of the time; more stable pressure inside.
Partially enclosed: buildings: large openings cause internal pressurization, increasing uplift.
Open buildings: wind flows freely inside, greatly increasing uplift on the roof surface.
4. Roof Area & Geometry
Larger roof areas experience higher total uplift forces.
Low-slope roofs (common in industrial buildings) are more vulnerable due to longer exposure to wind.
5. Roof Edges and Corners
Corners and edges experience the highest uplift forces.
These zones require special attention to purlin spacing, seam strength, and panel anchoring.
Wind uplift isn't applied equally across the entire roof. Building codes and engineering practices divide the roof into zones:
Zone 1 (Field): Central roof area, lowest uplift pressure
Zone 2 (Perimeter): Roof edges, higher pressure.
Zone 3 (Corners): The most critical zone, where wind uplift is the strongest
At roof corner areas, it may be necessary to add backing to increase the strength of the roofing system's fastening and to prevent the panels from blowing off in high wind conditions.
6. Panel Profile
Boltless, continuous systems with reinforced seams (like Double Seam) are more resilient.
Using high tensile strength steel (G550) helps reinforce the seam areas, as this type of steel has strong deformation resistance properties. This enhances the stability of the seam system, especially in areas exposed to high wind pressure
TSS Internal Testing: Simulating Uplift with FM 4474 (part of 4471)
At TSS, we take wind uplift seriously — both through in-house R&D and third-party validation. Here’s how:
Internal Testing to FM 4474
We’ve developed our own internal wind uplift testing machine, built according to the ANSI/FM 4474 standard, a key component of the FM 4471 roofing certification for wind resistance performance.
This standard outlines the method for testing roof panels and assemblies under simulated uplift forces, ensuring consistency and reliability.
Our panels are tested at multiple pressure intervals, monitoring deformation, seam integrity, and anchoring performance. This helps us refine our design, validate our connectors/clips, and improve structural resilience.
T-75DSF – FM 4471 Certified
Our T-75DSF double seam profile has passed the rigorous FM 4471 certification process, which evaluates the complete roofing assembly — not just the panel. This includes:
Wind uplift resistance (FM 4474)
Fire resistance (ASTM E108)
Hail resistance
You can find certified system assemblies for our T-75DSF profile on RoofNav, the FM Global database: https://roofnav.app.fmglobal.com/
Why It Matters: Safety and Performance
Whether you’re specifying metal sheet roofing for a new warehouse, upgrading a transportation terminal, or developing a factory in an exposed location — wind uplift resistance isn’t optional.
Poorly secured or under-designed roofs can lead to catastrophic failure, downtime, insurance claims, and worst of all — safety risks. Investing in tested and certified systems gives you peace of mind.
Poorly engineered roofing can fly off during storms, causing downtime, water damage, and safety risks. That’s why we design systems like our Double Seam boltless profiles to resist even extreme uplift pressures.
Comments