- Project plans
- Project activities
- Legislation and standards
- Industry context
Last edited 12 Apr 2019
An uplift force is any upward pressure applied to a structure that has the potential to raise it relative to its surroundings. Uplift forces can be a consequence of pressure from the ground below, wind, surface water, and so on.
Water pressure can exert an uplift force on a structure due to high rainfall, for example by causing clay soils to expand. This can be problematic if the upward forces are greater 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 wind uplift, which will vary according to location, terrain, height, size, shape, exposure and so on. Wind uplift occurs when the air pressure under the roof is greater than the air pressure above it. This can be exacerbated during high wind, as air infiltration into the building can increase pressure below the roof, whilst the speed of wind over the roof surface can reduce air pressure above it, in much the same way it does over an aircraft wing. This can cause damage to the roof if the difference in pressure becomes too great.
'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.
 Related articles on Designing Buildings Wiki
- Bearing capacity.
- Floor loading.
- Ground heave.
- Hurricane design considerations.
- Lateral loads.
- Limit state design.
- Roofing defects.
- Settlement of buildings.
- The design of temporary structures and wind adjacent to tall buildings.
- Types of structural load.
- Uniformly Distributed Load.
- Wind load.
Featured articles and news
How do we measure air tightness in buildings?
The Housing Infrastructure Fund
Encouraging access to local amenities and sustainable transport.
Publish your thought leadership articles on Designing Buildings Wiki – for free.
Competence Steering Group publishes interim proposals to deliver safer buildings.
Indoor environments should provide a multi-sensory experience.
We have a great range of introductory articles written by ECA.
7 of the most common myths, busted.
Consider a career in the electrotechnical industry.
Exploring local assets of community significance. Book review.