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.
In Guildford, as anywhere in Surrey, the price of a single-storey extension is driven mainly by size, materials and access. Across the South East our guide sits at £39,000–£84,000 with VAT, but restricted parking, a narrow side passage or extra preparation can move the figure either way. That is why every price we give follows a visit to the house.
- Guide price
- £39,000–£84,000 inc VAT
- Time on site
- 10–16 weeks on site
- Postcodes
- GU1, GU2 and GU4
- Planning rules
- England
- Local area
- Surrey
- Survey
- Free, with a written quote
How much does a single-storey extension cost in Guildford?
No two jobs cost exactly the same, but the ranges below give a fair picture of a single-storey extension in Guildford. Pricing for the South East runs about 12% above the national guide, and the overall guide is £39,000–£84,000 with VAT included. We'll confirm your figure after surveying the property for free.
| Type of job | What it usually involves | Guide in Guildford |
|---|---|---|
| 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 |
What moves the price up or down:
- Roof type, rooflights, lanterns and the amount of glazing
- 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
- Flat or pitched roof, with rooflights or a lantern if specified
- Electrics and plumbing by qualified trades, with certificates
- Windows and external doors, including bifolds if chosen
- 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.
Building traditions across Surrey also raise conservation and planning questions, so we check those for a single-storey extension in Guildford at the survey stage.
Planning and building rules in Guildford
Because Guildford falls under England's rules, the guidance below is the version relevant to you. Before sending a price, we check your property's position with the council.
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.
How does the job run?
We look at the job
We arrange a free site survey on a date convenient to you. We measure up, look at the existing structure and access, and discuss your plans for a single-storey extension so the price reflects your home.
Price and scope agreed
Next you receive a written quote with a fixed price for the agreed specification. It lists what is included, what is not, and how payments are staged, so you can compare it properly.
Plan and prepare
Once you accept, we agree start dates, order materials and deal with any planning, building control or neighbour notices the job needs. You'll know who is coming and when before work begins.
On site to finish
During the work we protect the areas around it and tidy up at the end of each day. Once complete, we check the finish, remove our materials and hand over paperwork such as building control sign-off where it applies.
Why homeowners choose us
Questions about a single-storey extension in Guildford
Do you cover Godalming, Woking and Aldershot?
Yes. As well as Guildford, we cover Godalming, Woking and Aldershot and the rest of Surrey. Our coverage is UK-wide, so the process is the same wherever you are: a free site survey, a quote in writing that fixes the price for the agreed scope, and one point of contact while the work is planned and carried out.
Do I need an architect for an extension?
You need proper drawings for an extension, but not always a full architect service. A designer or architectural technician can produce planning and building regulations drawings, and a structural engineer provides beam and foundation calculations. If you already have drawings, we price from them. If not, we can arrange the drawings and calculations as part of the project so everything is coordinated from the start.
How long does a single-storey extension take to build?
A single-storey extension usually takes 10–16 weeks on site, from digging foundations to final plastering. Bad weather, deep foundations or a complex roof can add time. Before work starts, allow several weeks for drawings, structural calculations and building control approval, and longer if planning permission is needed. We give you a stage-by-stage programme with your quote so you know what happens each week.
Can we stay at home during the build?
Most people stay at home while we build a single-storey extension, because the new structure goes up outside before we break through. The disruptive part is usually the last few weeks, when we open into the house and fit the kitchen. We put up dust screens, keep a safe route through the house and agree a temporary kitchen setup if needed. Water and power are only off for short, planned periods.
Can you combine a single-storey extension with other work?
Yes. Because we manage several trades under one contract, we can plan a single-storey extension alongside other work on your Guildford home, such as new windows with rendering, or a kitchen refit with an extension. Combining jobs can reduce repeat set-up such as scaffolding, skips and access, and every element is listed and priced in the same written quote.
Also covering areas around Guildford
Live in Guildford? Our coverage takes in the GU1, GU2 and GU4 postcode areas and reaches out to Godalming, Woking and Aldershot, so homes on the outskirts and in the next town along are included.