Last edited 11 Apr 2018

Uplift force

An uplift force is any upward pressure applied to a structure and its foundation that has the potential to raise it relative to the surroundings. Uplift forces can be a consequence of pressure from the ground below, expansive soil, wind, surface water, and so on.

Water pressure can exert an uplift force on a structure due to varying recharge rates, i.e. high rainfall, and if as a result the upward forces become higher than the forces being exerted downwards by the structure. To overcome this risk, the structure must be appropriately designed to provide greater resistance against uplift forces, and also a drainage system to relieve the water pressure.

For more information, see Ground heave.

All roofs are subject to the risks of wind uplift, which vary according to the structure’s location, height, size, roof design and exposure. 'BS EN 1991-1-4:2005+A1:2010 Eurocode 1. Actions on structures. General actions. Wind actions' defines the methodology for calculating likely wind loads which then allow a roofing system to be appropriately designed to withstand the wind loading.

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