A single-storey extension is a new ground-floor room built onto your house, usually at the rear or side, with its own foundations, walls and roof, creating a bigger kitchen, living space or bedroom without moving home.
Thinking about a single-storey extension in Banstead? We take charge of the whole project, co-ordinating every trade involved, and one person keeps you updated. Guide prices for the South East sit at £39,000–£84,000 including VAT, and a typical job takes 10–16 weeks on site. Your own figure depends on what the survey finds and the specification you settle on.
- Guide price
- £39,000–£84,000 inc VAT
- Time on site
- 10–16 weeks on site
- Postcodes
- KT17, KT18, SM2 and SM7
- Planning rules
- England
- Local area
- Surrey
- Survey
- Free, with a written quote
What should you budget for a single-storey extension in Banstead?
Use the table to gauge the cost of a single-storey extension in Banstead before we visit. Figures include VAT and are scaled for the South East, coming out about 12% above the national guide, which gives £39,000–£84,000 overall. After a free survey, you receive a fixed written price.
| Type of job | What it usually involves | Guide in Banstead |
|---|---|---|
| Small extension (8–12m²) | A modest rear or side extension, such as a utility room or a slightly larger kitchen. | £24,500–£45,000 |
| Typical rear extension (15–25m²) | A kitchen-diner or family room with bifold doors and a rooflight or lantern. | £39,000–£84,000 |
| Large or wrap-around (30m² plus) | A wrap-around or wide rear extension, often with structural steelwork into the house. | £78,000–£146,000 |
The main things that change the figure:
- Floor area, shape and number of corners
- Ground conditions, foundation depth and drains to divert
- Steelwork needed to open into the existing house
- Finishes, kitchen, flooring and heating specification
What’s included?
- Groundworks, foundations and below-ground drainage
- Cavity walls built and insulated to building regulations
- Electrics and plumbing by qualified trades, with certificates
- Windows and external doors, including bifolds if chosen
- Plastering, screed floor and internal doors
- Building control inspections and completion certificate
Local housing and a single-storey extension
Surrey has many Victorian and Edwardian villas, interwar semis in the commuter towns near London, and Arts and Crafts houses with tile-hanging and tall chimneys. Bargate stone appears around Godalming, and large detached homes are common in Guildford, Woking, Weybridge and the Surrey Hills villages.
Larger homes often take kitchen extensions, bifold doors, landscaping and driveway renewal. Interwar semis suit loft and side extensions, while tile-hung and period properties may need roof and hanging-tile repairs.
These patterns matter for a single-storey extension: older walls, roofs and floors in Banstead can need different materials or extra preparation compared with newer homes.
Planning and building rules in Banstead
England, Wales, Scotland and Northern Ireland each handle planning a little differently. Banstead comes under England, covered below, and we raise any questions with the council before your quote is finalised.
In England, many single-storey rear extensions are permitted development: typically up to 3 m deep on a semi-detached or terraced house and 4 m on a detached house, no more than 4 m high, and covering no more than half the land around the original house. Larger rear extensions can go through the prior approval process. Side extensions, flats, listed buildings, conservation areas and homes where permitted development rights have been removed need planning permission.
Building Regulations approval is needed for almost every extension, covering foundations, structure, insulation, drainage, ventilation and fire safety. If the work is on or near a shared wall or boundary, the Party Wall etc. Act 1996 may apply.
Rules change and every property is different, so we check the planning history and constraints for your address before we quote.
From survey to handover
Free site survey
First, someone visits your home in Banstead to see the space, take measurements and note anything that could affect the work, such as access or the condition of what is there. There is no charge for this visit.
Written quote
The quote arrives in writing, not over the phone. It covers the full scope, the finishes you've chosen, any exclusions and the payment schedule, with a fixed price tied to that specification.
Getting ready
Preparation matters as much as the build. We agree access, parking and working hours with you, order materials in good time, and confirm any permissions so the job isn't held up once it starts.
On site to finish
The job proceeds in the order set out in the programme, with dust and debris kept under control. Finally we tidy away, inspect the work together and pass the finished project over to you with its paperwork.
How we work
Common questions
How much does a single-storey extension cost?
A typical single-storey rear extension of 15–25m² costs £39,000–£84,000, built to a plastered finish ready for your kitchen and decoration. As a guide, allow roughly £1,600–£2,800 per square metre plus fixed costs for groundworks, steelwork and fees. Smaller extensions cost more per square metre. The kitchen, flooring and large glazed doors are usually the biggest extras. We confirm a fixed price for the agreed specification after the survey.
Can I stay at home during the work?
In most cases, yes. Most people can live at home throughout, and we plan the work to keep disruption down by protecting floors, agreeing working hours and keeping access routes clear. Bigger jobs affecting kitchens, bathrooms or heating may mean a short spell with reduced facilities, and we talk this through with you at the survey.
Who do I deal with during the job?
One point of contact manages your project from survey to handover. They schedule the trades working under our contract, keep you updated on progress, and are the person to call with any question. You don't need to coordinate builders, electricians or decorators separately, because that is part of what we do.
What does a typical extension build look like week by week?
A typical single-storey extension follows the same order: clearing the site and digging foundations, building walls up to roof level, then fitting the roof and windows to make it weathertight. Electrics, plumbing, insulation and plastering follow. The last stage is opening into the house, laying the screed and fitting doors and finishes. Building control inspects at key stages, and we book those visits for you.
What is the Party Wall Act and does it apply to me?
The Party Wall etc. Act 1996 applies in England and Wales only. In England and Wales, it requires you to give notice to neighbours before certain work on or near a shared wall, such as digging foundations within 3m of their building and deeper than its footings. Neighbours can agree or appoint a surveyor. Scotland and Northern Ireland have no equivalent Act, though general rights still apply. We identify whether notices are needed during the survey.
Nearby towns
Coverage for Banstead spans KT17, KT18, SM2 and SM7. Close by, Sutton, Ewell and Epsom are covered too, and the rest of our UK-wide area follows the same survey-then-quote process from start to finish.