Flat Roof Wind Uplift

Areas that are commonly affected by wind uplift due to loss of laminar flow are upwind eave edges upwind rakes upwind corners and the downwind side of ridges.

Flat roof wind uplift.

This means that before installing a flat roof in a higher risk area a wind calculation needs to be carried out to ensure that every component is capable of withstanding wind uplift. Wind uplift calculations to ensure that every sarnafil roofing system will stay on the building no matter what the geographic location or height of the building the sika sarnafil technical services department calculates the wind load on every individual roof. 2012a 2012b and the maximum pressure coefficient of 0 8 on the windward roof surface of the flat roof building with frac h w le. Ensuring the right method of attachment is chosen for the project.

6a the roof is flat and out of all the incident wind angle the maximum pressure coefficient is found to be as 0 4 which is less than the maximum pressure coefficient of 0 9 by wind tunnel experimental study and the maximum pressure coefficient of 0 98 by cfd simulation study on flat roof without opening as described by roy et al. If wind uplift raises a portion of the roof covering more of the surface of that material will be exposed. The topographic factor kzt accounts for effect of wind speed up over isolated hills and escarpments sect. At the same time internal air pressure increases due to air infiltration through openings cracks etc.

When opting for a polymeric single ply membrane roofing solution one of the key documents is the wind uplift calculation and not just for mechanically fastened roofs they can be just as important for adhered roofs when in certain locations or possibly with a higher risk of exposure. The result is a net upward force on the roofing system. For flat roofs roof angle 0 degrees either gable or monoslope may be used. This force is referred to as wind uplift.

This exerts a significant amount up pressure against the structure and pushes air upwards. Wind uplift tests performed by ul have shown that polyurethane foam actually enhances the wind uplift resistance of the substrate. The risk of rain although called a flat roof a flat roof is actually very slightly pitched meaning that rain is able to drain away. Wind uplift occurs when high levels of wind come into contact with a building.

When pressure builds underneath a roof and is greater than the pressure above it this uplift is created but there are many other factors that contribute to wind uplift and its effects on your building. As wind flows over the building the pressure directly above the surface of the roof decreases.