Synclastic
Tensile surfaces, that is, surfaces which carry only tension and no compression or bending, rely on double curvature for their stability. Stability is provided by the opposition of two curvatures which enable the surface to be tensioned without losing its form.
Tensioning the surface reduces its elasticity and so its tendency to deform under load, and the curvature itself means that the surface will deform less for any given extension.
Tensile surfaces can be used in buildings to create thin, long span enclosures, such as roofs for sports stadia, shopping centres, atria and so on. Typically they are constructed using a PVC-coated polyester or PTFE coated glass fabric, typically just 1 mm thick.
Double curvature can be anticlastic or synclastic.
![]() |
![]() |
Anticlastic (saddle-shaped). | Synclastic (dome-shaped) |
Synclastic surfaces are those in which the centres or curvature are on the same side of the surface. This is a dome-shape. This can be created with an architectural fabric by inflation – that is, air pressure within the dome maintains the form of the surface when it is tensioned, rather than the opposition of the curvatures.
This is opposed to anticlastic surfaces, which are those in which the centres of curvature are located on opposing sides of the surface. This is commonly-described as a saddle shape. A hyperbolic paraboloid is an anticlastic surface.
[edit] Find out more
[edit] Related articles on Designing Buildings Wiki
- Anticlastic.
- Barrel vault.
- Biaxial bending.
- Concept structural design of buildings.
- Conoid shell.
- Fabric structures.
- Hyperbolic paraboloid.
- Limit state design.
- Structural engineer.
- Tensegrity.
- Tensile structures.
- The development of structural membranes.
- The structural behaviour of architectural fabric structures.
- Types of dome.
- Why are domes popular?
Featured articles and news
ECA Industry Awards 2024 shortlist revealed
22 leading businesses from across the electrotechnical and engineering services sector.
Government unveils Skills England strategy
Skills England to transform opportunities and drive growth.
New Government Hub for York Given Planning Green Light
For up to 2,600 civil servants, due for completion by 2028.
Construction Skills Certification Scheme cards
July update on Professionally Qualified and Academically Qualified Person Cards.
BSRIA Briefing 2024, November 22
Sustainable Futures: Redefining Retrofit for Net Zero Living.
The CLC on driving competency in the retrofit sector
Previously published roadmap on skills for net zero.
The first labour government King's speech in fifteen years
Construction industry reactions, support and some concern.
CIOB Retrofit of Buildings Technical Information Sheet
What retrofit is, the approach to be taken and processes to be followed.
Adapting Historic Buildings for Energy and Carbon Efficiency
Historic England advice note 18, free download published.
10 retrofit projects revisited 10 years after completion.
Information orders, building liability orders and SPVs
Key BSA terms and how they impact special purpose vehicles.
Listed despite problems with its design.
Zen and the art of cycling exploration.
Design Council Homes Taskforce launched
To support government 1.5 million homes target within UK climate commitments.