- 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
Seven steps to defining a digital twin.
Achieving air tightness in buildings.
What are the benefits of smart homes for Millennial end-users?
How dynamic briefing can result in an efficient project.
Achieving sustainable roads funding in England.
Your chance to comment on the draft BS 851188 - flood resistance products and flood protection products.
Rebuilding could take 20 to 40 years.
RSHP’s high-rise residential towers win a tall buildings award for excellence.
BSRIA study reveals strong growth in 2018.
Dame Judith Hackitt confirmed as keynote speaker – one year on from the Hackitt Report.
Save £100 on tickets.
Modern slavery in the construction sector.
What to bear in mind when claiming damages in construction.
How do we achieve sustainable clean-water infrastructure for all?