A wind uplift test is performed to objectively assess the wind resistance of a roof build-up or roofing system. This is essential to ensure that the roof structure can withstand the wind loads expected for a specific building — based on its location, height, and geometry.
During the test, the full roof system is built up as it would be in practice — including all layers such as the vapour barrier, insulation, and waterproofing membranes. This build-up is then placed in a test rig where negative pressure is applied in controlled cycles, with the load gradually increasing.
The results of the test are recorded in a test report. The key outcome is the maximum load that the system successfully withstands without damage or detachment — referred to as the tested value (Wtest).
To ensure safety in real-world applications, a safety factor is applied to Wtest in line with local regulations, resulting in the admissible value (Wadm).
Wadm is used in the wind load calculation during the design of a roof. This verifies whether the wind resistance of the tested system is higher than the expected wind load (Wrec) for different roof zones (such as corners, edges, and central areas).
Only when Wadm ≥ Wrec can the roof system be considered sufficiently wind-resistant.
Why is this test important?
- It provides objective, reproducible data on the wind resistance of a roof system.
- It helps verify the suitability of a specific build-up for a particular project location.
- It serves as a technical and legal reference in case of damage or disputes.
- It offers greater confidence and security for designers, contractors, and building owners.
By correctly interpreting wind uplift tests and applying the appropriate safety margins, the safety and durability of flat roof systems can be significantly improved.