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.
We take on a single-storey extension throughout New Milton and the surrounding BH25 postcodes, as well as in Christchurch, Bournemouth and Hythe. The guide range for this work in the South East is £39,000–£84,000 including VAT; where your project falls depends on its size, the materials you pick and how easy the site is to reach. A free survey turns that range into a fixed figure.
- Guide price
- £39,000–£84,000 inc VAT
- Time on site
- 10–16 weeks on site
- Postcodes
- BH25
- Planning rules
- England
- Local area
- Hampshire
- Survey
- Free, with a written quote
Single-storey extensions prices in New Milton
These are guide costs, not quotes. For a single-storey extension in New Milton the range is £39,000–£84,000, VAT included, reflecting prices in the South East that are about 12% above the national guide. Once we have visited for a free survey, you get a firm figure for the scope you approve.
| Type of job | What it usually involves | Guide in New Milton |
|---|---|---|
| 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 |
Expect these to shape the final quote:
- 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
Scope of the work
- Groundworks, foundations and below-ground drainage
- Flat or pitched roof, with rooflights or a lantern if specified
- Steel beams to open into the existing house
- Electrics and plumbing by qualified trades, with certificates
- Windows and external doors, including bifolds if chosen
- Plastering, screed floor and internal doors
What are homes like around New Milton?
Southampton and Portsmouth have dense Victorian terraces, with plenty of post-war rebuilding after wartime bombing. Winchester keeps Georgian and medieval streets, Basingstoke expanded rapidly with 1960s and 1970s estates, and New Forest villages feature cob, thatch and brick. Brick and flint is common on the chalk downs, and new estates ring most towns.
Coastal areas along the Solent face salt and wind, while chalk downland is better drained but exposed; inland clay can move in dry summers.
None of this holds for every street in New Milton, which is why we look at your actual house before pricing a single-storey extension rather than assuming from its age alone.
Planning and building rules in New Milton
For anyone in New Milton, the relevant framework is England's. The summary below is general, so we always contact the council about your address before putting a price in writing.
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?
Free site survey
It starts with a survey at the property, free of charge. We check condition, access and services, ask how you want the finished result to look, and answer any questions you have about a single-storey extension.
Your fixed price
After the survey we send a quote for a single-storey extension that fixes the price for the scope we've agreed. If you want to change materials or scope, we revise it in writing before anything is booked.
Getting ready
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
On site, the agreed plan is followed and any change is put in writing first. At completion we do a final clean, go through the snagging list with you and leave you with the relevant documents.
How we work
Frequently asked questions
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.
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.
What happens at the survey?
We visit your home at a time that suits you, look at the area involved, take measurements and check access, condition and any services that might be affected. We talk through what you want from a single-storey extension, explain the options and answer questions. There is no charge and no obligation; afterwards we send a written quote.
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.
Do I need planning permission in New Milton?
It depends on the work, the size of the project, your property type and whether the building is listed or in a conservation area. New Milton is in England, so England's rules apply. Many smaller jobs need no planning application, but some still need building control approval. We check what applies to your address before quoting.
Also covering areas around New Milton
Live in New Milton? Our coverage takes in the BH25 postcode areas and reaches out to Christchurch, Bournemouth and Hythe, so homes on the outskirts and in the next town along are included.

