UK construction glossary

Plain-English definitions of construction terms used in UK quotes, building regs, planning, and trade work. Searchable A–Z, written for trades and customers alike.

Most-searched terms

• AAV (Air Admittance Valve) — A one-way valve that lets air into a drainage system to prevent siphoning, used as an alternative to extending a soil vent pipe through the roof. Saves cost on shorter waste runs.
• Building Regulations — The minimum legal standards for design, construction, and alterations to virtually every building in England and Wales. Separate but similar regulations apply in Scotland and Northern Ireland.
• Cavity wall — Two parallel walls (typically brick + block) with an air gap between them. The cavity may be filled with insulation. Standard for new-build UK homes since the 1920s.
• DPC (Damp Proof Course) — A horizontal barrier in a wall (typically of plastic or slate) that prevents rising damp. Required by Building Regulations near ground level.
• EPC (Energy Performance Certificate) — A rating (A–G) of a property's energy efficiency. Required when selling or letting a UK home. Valid for 10 years.
• FENSA — A UK trade body whose members can self-certify replacement windows and doors as compliant with Building Regulations Part L.
• First fix — The structural and behind-walls work in a build (carcassing, plumbing pipes, electrical cables) done before plastering.
• Gas Safe Register — The official register of gas engineers qualified to work on gas appliances in the UK. Mandatory for all gas work.
• Joist — A horizontal structural member (usually timber or steel) that supports floors or ceilings. Span and depth determined by load.
• K-Rend — A premium polymer-modified silicone-based render used widely in the UK. Breathable, water-repellent, and crack-resistant.
• Lintel — A horizontal load-bearing beam over an opening (window, door) that transfers the load from above to either side. Steel, concrete, or stone.
• Listed Building Consent — A separate consent required (in addition to planning permission) for any alterations to a listed building that affect its character.
• NHBC — National House-Building Council. Provides 10-year warranties on new-build homes. Most major UK builders are NHBC members.
• NICEIC — A UK certification body for electrical contractors. Self-certifies Part P compliance.
• Party Wall Agreement — A formal written agreement between adjoining owners required under the Party Wall Act 1996 for certain works near or on a shared wall.
• Permitted Development — A national grant of planning permission allowing certain types of building work without an individual planning application, within strict size limits. See full explainer.
• RIBA — Royal Institute of British Architects. The professional body for UK architects.
• RICS — Royal Institution of Chartered Surveyors. The professional body for UK surveyors.
• RSJ (Rolled Steel Joist) — Generic name for a steel beam used to span openings, usually after removing a load-bearing wall. Sized by structural engineer calculation.
• Second fix — The finishing work in a build (decoration, plumbing fixtures, electrical fittings, kitchen install) done after plastering.
• SVP (Soil Vent Pipe) — The vertical drainage pipe carrying foul waste from an upstairs WC, basin, or shower to the underground drains.
• TrustMark — A government-endorsed scheme for trades meeting certain quality and consumer protection standards.
• UPVC — Unplasticised PolyVinyl Chloride. The most common UK material for replacement windows and doors. Cheap, low-maintenance, durable.
• VAT (5% reduced rate) — Some construction works qualify for the 5% reduced rate of VAT (not standard 20%) — typically renovations of properties empty 2+ years and certain energy-saving installations.
• Zinc cladding — A premium architectural metal cladding, increasingly popular on UK extensions for its modern look and longevity. Pre-weathered varieties available.

About this glossary

This is a working glossary of terms commonly used in UK construction quotes, building regulations, planning, and trade work. We focus on terms you're likely to see on a quote or in a builder's conversation, not exhaustive industry jargon.

If a term you'd like defined isn't here, let us know and we'll add it. Definitions are written for trades, customers, and accountants — anyone who reads a quote without specialist construction training.

Related

• What should a construction quote include
• How to write a builder's quote
• What is permitted development

Last reviewed: May 2026