Construction Jargon Explained: Site Terms in Plain English

‍‌​‌​‌‌‌‌‌‌​​‌​‌​​​‌‌​​​‌​‌​‌​‌‌‍# S2. The jargon - construction terms in plain English

1. THE SHORT VERSION

Construction is full of jargon. A lot of it is simple when you strip it down.

This page tells you what common site terms actually mean, in plain English, and why you should care.

2. HOW TO USE THIS

You see a word on drawings, RAMS or in a WhatsApp from the gaffer.

You look it up here.

You get a one‑line meaning and, where it matters, what it means for your day on site.

No law, no fluff, just "this is what they're talking about".

3. PEOPLE AND ROLES

• Client – The person or company paying for the job. They want the thing built.
• Principal contractor (PC) – The main firm running the site. They plan and control most of the work.
• Subbie / subcontractor – A company hired by another contractor to do a specific trade (brickwork, roofing, M&E).
• Ganger / gang – The working foreman for a crew. They run the day‑to‑day work for their team.
• Site manager / agent – Person on site who manages the project day to day – programme, trades, safety.
• Engineer / setting‑out engineer – The person who sets out lines and levels, checks measurements, marks positions.
• QS (Quantity Surveyor) – Looks after costs, measurements, variations and payments.
• Building control / inspector – Checks work meets building regs. Can sign things off or ask for changes.

4. DRAWINGS, DOCUMENTS AND PLANS

• GA drawing (General Arrangement) – The main plan that shows what goes where in overall layout.
• Detail drawing – Close‑up of one area showing exactly how to build or fix something.
• Section – A cut‑through view of the building, like slicing it and looking from the side.
• Spec / specification – Written list of standards, materials and methods to use.
• As‑built – Final drawing showing what was actually built, including changes.
• RAMS – Risk Assessment and Method Statement. What can go wrong and how you're meant to do the job safely.
• Program(me) – The schedule. What gets done when and in what order.
• Snag / snagging list – List of defects or unfinished bits that need sorting.

5. SITE AND GROUND

• Site boundary – Fence or line that marks the edge of the job. Inside it = site rules.
• Welfare – Toilets, wash, drinking water, somewhere to sit down for breaks.
• Compound – Main area with cabins, stores, parking and welfare.
• Brownfield – Land that's been built on before (old factories, yards).
• Greenfield – Fresh land that hasn't been built on. Fields, open ground.
• Excavation / dig – Hole or trench in the ground. Depth and support matter.
• Spoil – Waste soil or material dug out of the ground.

6. STRUCTURE AND BUILDING BITS

• Foundations / footings – Concrete at the bottom that spreads the load into the ground.
• Slab – Big flat chunk of concrete (ground floor slab, roof slab).
• Lintel – Support over an opening like a window or door.
• Stud / stud wall – Light framed wall (usually timber or metal studs with boards).
• In situ – Built or poured in place, not pre‑made in a factory.
• Precast – Concrete elements cast in a factory and brought to site.
• Envelope – The outside skin of the building: walls, roof, windows, doors.

7. ROOFS AND FLOORS

• Joist – Repeating timbers or steel that support a floor or roof.
• Decking (roof or floor) – Sheets laid over joists or beams to form a surface.
• Warm roof / cold roof – Where the insulation sits. Warm = insulation above structure; cold = insulation between/under.
• Flat roof – Roof with a very small fall; still needs slope for drainage.
• Pitched roof – Sloping roof with tiles, slates, sheets etc.

8. SERVICES AND M&E

• M&E / MEP – Mechanical and Electrical / plus Plumbing. All the services: heating, power, water, ventilation.
• First fix – work: cables, pipes, framing before finishes go on.
• Second fix – Visible work: sockets, switches, radiators, sanitaryware, joinery.
• Plant room – Room with boilers, pumps, AHUs, main kit.

9. SAFETY AND COMPLIANCE TERMS

• PPE – Personal Protective Equipment: boots, hard hat, hi‑vis, gloves, goggles, etc.
• Permit to work – Written permission for high‑risk jobs (hot works, confined space, live services).
• Temporary works – Temporary structures like scaffolds, props, formwork, crash decks until the permanent works are self‑supporting.
• Method statement – Step‑by‑step how the job will be done, including safety controls.
• Toolbox talk – Short safety talk on one topic, usually at the start of a shift.

10. SLANG YOU'LL HEAR A LOT

(Varies by region and site – this is what it usually means.)

• Plant – Machinery and equipment: diggers, telehandlers, MEWPs, generators.
• Cabin – Site office / welfare unit.
• The office – Where the management sit on site (can be a cabin).
• Genny – Generator (often for cable‑locating kit too).
• Banksman / banks person – The one guiding plant or vehicles.
• Snagging – Fixing defects or minor issues near the end of the job.
• Program's slipping – The job is behind schedule; expect pressure.

WHAT TO DO NEXT

• Bookmark this page and come back when you hear something you don't recognise.
• Before your first day, read through the safety and compliance terms so they are not new to you on site.
• Ask questions on site if someone uses a word you don't know - nobody expects you to know everything on day one.
• Look at the drawings for your next job and see how many of these terms you can spot.

SOURCES

• Build UK – Common terms and site induction guidance, 2025.
• CITB – Industry terminology and training resources.
• HSE – Health and safety in construction terminology. https://www.hse.gov.uk/construction/

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