A double-storey extension adds two floors of new space to your house in one build, typically a larger kitchen or living room downstairs with an extra bedroom, bathroom or en-suite above, sharing one set of foundations and one roof.
Whatever prompted you to look into a double-storey extension, whether wear and tear, a growing family or plans to move, we can survey your Andover home and give you a price in writing. Homes in the South East typically come in at £67,000–£134,000, VAT included, for this kind of work. We also cover Winchester, Newbury and Salisbury, and the same steps apply wherever you are in Hampshire.
- Guide price
- £67,000–£134,000 inc VAT
- Time on site
- 14–22 weeks on site
- Postcodes
- SP10
- Planning rules
- England
- Local area
- Hampshire
- Survey
- Free, with a written quote
Double-storey extensions prices in Andover
To help you plan, we show what a double-storey extension typically costs in Andover instead of holding figures back for a sales call. The range is £67,000–£134,000 with VAT, using rates in the South East that are about 12% above the national guide. A free survey then fixes your actual price.
| Type of job | What it usually involves | Guide in Andover |
|---|---|---|
| Small (15–20m² total) | A compact rear or side extension adding a small room on each floor. | £45,000–£73,000 |
| Typical (30–40m² total) | A larger kitchen or living room below with a double bedroom or en-suite above. | £67,000–£134,000 |
| Large (50m² plus total) | Wide or deep extensions, often with a new bathroom, steelwork and high-spec glazing. | £112,000–£202,000 |
The main things that change the figure:
- Combined floor area across both storeys
- How the new roof joins the existing roof
- Foundation depth, ground conditions and drains to divert
- Scaffolding duration, access and the level of finishes
What does the job include in Andover?
- Groundworks, foundations and below-ground drainage
- Insulated cavity walls with brick or render to match the house
- First-floor joists, stud walls and new openings upstairs
- Electrics, plumbing and heating by qualified trades, with certificates
- Windows, external doors, plastering and internal doors
- Building control inspections and completion certificate
Building in Andover
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.
So when we survey a Andover property for a double-storey extension, the first step is working out how it was built and what has been changed since.
Planning and building rules in Andover
Planning law differs across the UK. For a home in Andover, it is the England rules below that count, and we check them with the council ahead of any quote.
In England, a two-storey rear extension can only be permitted development if it is no more than 3 m deep, at least 7 m from the rear boundary and finished to match the house. Most double-storey and all two-storey side extensions need full planning permission.
Building Regulations approval is needed, with structural calculations for beams, foundations and the roof. The Party Wall etc. Act 1996 often applies on semi-detached and terraced houses.
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
Book a visit and we'll come to you. The survey covers measurements, the state of what's there now and any obvious constraints, so the price that follows is based on your actual home, not an average.
Quote in writing
We put everything into a written, fixed-price quote: the specification, what's excluded, staged payments and the expected time on site. Take whatever time you need to decide; there's no pressure to commit.
Dates and permissions
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.
Build and hand over
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.
What you can expect from us
Frequently asked questions
How is the new roof joined to the existing house?
The new roof is usually tied into the existing roof so the two read as one. On a rear extension this often means a lower ridge or a hipped end, with valleys where the slopes meet. We strip back some existing tiles, fix new rafters and battens, and lay matching tiles or slates. Lead or proprietary flashings seal the junctions so water runs off properly.
Do I need planning permission in Andover?
It depends on the work, the size of the project, your property type and whether the building is listed or in a conservation area. Andover 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.
Can the new upstairs room have its own bathroom?
A new upstairs room can usually have an en-suite, provided waste pipes can reach the soil stack or a new one can be installed. Running the waste pipe to the right falls is the main design question, and a pumped system is an option where gravity will not work. We plan bathroom positions at the design stage so pipes, ventilation and insulation are built in rather than added later.
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.
How much does a double-storey extension cost?
A typical double-storey extension of 30–40m² across both floors costs £67,000–£134,000, built to a plastered finish. As a rough guide, allow around £1,400–£2,600 per square metre plus fixed costs for groundworks, scaffolding and fees. The second storey usually costs less per square metre than the first, because foundations and roof are shared. Bathrooms upstairs and a complex roof add most. We confirm a fixed price after the survey.
Also covering areas around Andover
Coverage for Andover spans SP10. Close by, Winchester, Newbury and Salisbury are covered too, and the rest of our UK-wide area follows the same survey-then-quote process from start to finish.