Wind Uplift

Wind uplift is one of the most significant structural forces acting on a roof. When wind flows over a building, it accelerates as it passes over the roof surface, creating a low-pressure zone above the roof (similar to the lift generated by an aeroplane wing). This low pressure generates an upward suction force that acts on the entire roof surface. The uplift force is not uniform — it is highest at the edges, corners, and ridge of the roof, and lower in the central field area. This is why Australian Standard AS 4055 defines different wind zones on the roof, each requiring specific fixing densities. Wind uplift is expressed in kilopascals (kPa) and is calculated based on the regional wind speed, the terrain category (how exposed the site is), the building height, the roof pitch, and the distance from the roof edge. In severe wind events, the uplift force at the corners and edges of a roof can exceed 3 kPa (approximately 300kg per square metre) — enough to tear poorly fixed sheets from the roof structure. In Gippsland, wind uplift is a significant design consideration, particularly for properties in exposed locations such as coastal South Gippsland, open farmland in the Latrobe Valley, and elevated sites in the Baw Baw and Strzelecki Ranges. Town & Country Roofing calculates wind loads for every roof installation and ensures the screw pattern, fixing type, and structural connections meet the requirements of Australian Standards.