Permanent structure
In reality no structures are truly permanent. They will degrade over time and will ultimately fall into disrepair, fall out of use or will be demolished.
However, a structure may be considered to be permanent if it is designed for a long-term use, rather than short-term or temporary use. The duration that might be considered ‘long term’ will vary depending on the design life of the structure.
BS EN 1990, Eurocode - Basis of structural design, (Eurocode 0) gives indicative design lives for various types of structure:
- Category 1: Temporary structures, not including structures or parts of structures that can be dismantled with a view to being re-used – 10 years.
- Category 2: Replaceable structural parts, e.g. gantry girders, bearings – 10 to 25 years.
- Category 3: Agricultural and similar buildings – 15 to 30 years.
- Category 4: Building structures and other common structures – 50 years.
- Category 5: Monumental building structures, bridges and other civil engineering structures – 100 years.
The actual life of a structure will vary depending on factors including:
- Materials.
- Workmanship.
- Moisture, humidity and rain.
- Wind.
- Temperature and temperature fluctuations.
- Pollution.
- Solar radiation.
- Maintenance.
- Intensity of use.
In legal terms, The Town and Country Planning (General Permitted Development) Order 1995 defines a temporary use as one that does not exceed 28 days in any calendar year. Beyond this, under normal circumstances, a structure would be considered to be ‘permanent’ and so would require planning permission. However, this is reduced to 14 days for some uses, and only certain temporary uses are permitted at all without planning permission. See Temporary use for more information.
Schedule 2 of the building regulations defines a temporary building as, ‘A building that is not intended to remain where it is erected for more than 28 days’. For more information see: Temporary structure.
During the construction process, it is normal to distinguish between permanent works and temporary works. Temporary works may also be regarded as temporary structures comprising an arrangement of elements that are necessary only during the construction process itself. These can include scaffolding, formwork, trench supports and so on.
Temporary works are defined in BS5975: 2008 + A1: 2001 Code of Practice for Temporary Works Procedures and the Permissible Stress Design of Falsework as ‘parts of the works that allow or enable construction of, protect, support or provide access to, the permanent works and which might or might not remain in place at the completion of the works.’
[edit] Related articles on Designing Buildings Wiki
Featured articles and news
Myths and top tips.
CLC plans to ease impact of construction inflation.
BG 50 & VDI 2035 – your questions answered.
Types of domestic heating systems.
Will the way we heat homes change when winter comes ?
Extended reality in a post-pandemic world.
Can XR technology be leveraged in design & construction?
Or are you capping.
STEM ambassadors needed for ICE CityZen award.
Digital gaming competition for UK students aged 16 to 18.
Heritage protection in England vs Australia.
Fire doors and the Fire Door Inspection Scheme.
Three-quarters of fire doors fail inspections
UN International Day for Biological Diversity, May 22.
The role of geoparks, biospheres and world heritage sites.
BSRIA conference 2022, June 23.
Just one month to go ! Find out more here.
Restoring Broadbent’s Bath House
A new gallery for the University of Huddersfield.
Corruption in the construction industry.
What will it take to stop it ?
To celebrate world bee day 2022 !
Just one month until the changes to part L come into effect.
Not forgetting part F and the new part overheating part O.
Heat Pump demand rises by one quarter.
As energy prices jump up in cost.
With people in the UK from Ukraine.
Industry leader Steve Murray takes on role.
An abundant and versatile building material.
How overheating complicates ending gas in the UK.
600,000 heat pump installations targeted per year by 2028.
Cost planning, control and related articles on DB.
Helping prevent those unwanted outcomes.