Glossary
The planning and building terms you will meet when extending a house, explained simply.
- Article 4 direction
- A council order removing some permitted development rights in an area, so works that would normally be allowed need planning permission.
- Building control
- The service, run by councils or registered building control approvers, that checks building work meets the building regulations.
- Building notice
- A way of getting building regulations approval in England and Wales where work is inspected as it goes, without full plans being checked first.
- Building warrant
- In Scotland, the approval needed from the council before building work starts.
- Build-over agreement
- Consent from the water company to build over or near a public sewer.
- Completion certificate
- The document issued when building control is satisfied the work meets the regulations.
- Conservation area
- An area of special architectural or historic interest where planning controls are tighter.
- Curtilage
- The land around a house that belongs to it, such as the garden and driveway.
- Eaves
- The lower edge of a roof where it meets or overhangs the wall.
- Full plans application
- A building regulations application where drawings are checked and approved before work starts.
- Householder application
- A planning application for works to an existing house, such as an extension.
- Lantern
- A raised glazed roof structure that lets light into the room below, common on flat-roofed extensions.
- Lawful development certificate
- A council certificate confirming that proposed works are lawful, for example because they are permitted development.
- Lintel
- A beam over a door or window opening that carries the wall above.
- Original house
- For permitted development, the house as first built, or as it stood on 1 July 1948 if older.
- Outrigger
- The narrower rear wing of many Victorian and Edwardian terraced houses.
- Party wall
- A wall shared by two properties, or on the boundary between them.
- Party wall award
- A document drawn up by surveyors setting out how work affecting a party wall will be carried out.
- Permitted development
- National rights that allow some extensions to be built without a planning application.
- Prior approval
- A light-touch application in England for a larger single-storey rear extension, where neighbours are consulted.
- Rooflight
- A window set into a roof, flat or pitched.
- Side return
- The narrow strip of land beside the rear outrigger of a terraced house.
- Steel beam (RSJ)
- A steel beam used to carry loads over a wide opening, for example where a rear wall is removed.
- Structural calculations
- An engineer's calculations showing that beams, foundations and other elements are strong enough.
- U-value
- A measure of heat loss through a building element; the lower the number, the better the insulation.
- Warm roof
- A flat roof with the insulation above the structural deck, keeping the structure warm and dry.
- Wraparound extension
- An L-shaped extension that combines a side return and a rear extension.