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.
Daventry sits within our coverage for a double-storey extension, as do neighbouring Rugby, Northampton and Leamington Spa. Before giving a price we want to see the property: the condition of what's there now, the access, and anything that might need extra work. The guide range for the East Midlands is £58,000–£115,000 including VAT, and your written quote will spell out exactly what that covers.
- Guide price
- £58,000–£115,000 inc VAT
- Time on site
- 14–22 weeks on site
- Postcodes
- NN11
- Planning rules
- England
- Local area
- Northamptonshire
- Survey
- Free, with a written quote
Double-storey extensions prices in Daventry
The table below shows guide prices for a double-storey extension in Daventry. They are based on rates in the East Midlands, which run about 4% below the national guide, giving an overall range of £58,000–£115,000. All figures include VAT and are firmed up after a free site survey.
| Type of job | What it usually involves | Guide in Daventry |
|---|---|---|
| Small (15–20m² total) | A compact rear or side extension adding a small room on each floor. | £38,500–£62,000 |
| Typical (30–40m² total) | A larger kitchen or living room below with a double bedroom or en-suite above. | £58,000–£115,000 |
| Large (50m² plus total) | Wide or deep extensions, often with a new bathroom, steelwork and high-spec glazing. | £96,000–£173,000 |
What moves the price up or down:
- 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
Scope of the work
- Groundworks, foundations and below-ground drainage
- Roof structure tied into the existing roof, tiled to match
- Scaffolding for the full build, erected and inspected
- Electrics, plumbing and heating by qualified trades, with certificates
- Windows, external doors, plastering and internal doors
- Building control inspections and completion certificate
Homes in Northamptonshire
Orange-brown ironstone is the signature material of many Northamptonshire villages, with limestone and Collyweston stone-slate roofs in the north-east. Northampton has Victorian terraces from its shoemaking era, Corby expanded as a post-war steel town, and Wellingborough, Kettering and Daventry have interwar, post-war and recent estates.
Ironstone cottages often need lime repairs and careful repointing. Terraces suit loft conversions and kitchen extensions, while estate homes commonly take garage conversions, porches and driveways.
In Daventry, as elsewhere in Northamptonshire, we take the building's age and construction into account before recommending anything, because both can change what is involved in a double-storey extension.
Planning and building rules in Daventry
England, Wales, Scotland and Northern Ireland each handle planning a little differently. Daventry comes under England, covered below, and we raise any questions with the council before your quote is finalised.
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
A visit to your home
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 double-storey extension.
Your fixed price
We turn the survey notes into a written quote. The price is fixed for the specification we agree, and the document sets out materials, scope and payment stages in plain language.
Getting ready
Next comes planning the work itself. We set a start date that suits you, line up the right trades, and make sure any approvals for a double-storey extension are in place before the first day on site.
Finish and handover
The work is carried out to the agreed specification, with floors and furniture protected and the site kept tidy. At the end we clean up, walk through the finished job with you and hand over any certificates.
Why homeowners choose us
Questions about a double-storey extension in Daventry
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.
Is the price fixed?
Yes, for the specification we agree. Your written quote sets out exactly what is included at a fixed price. It only changes if you ask for something different, or if a problem the survey could not reasonably reveal later needs extra work. In either case we explain the change and confirm it in writing before going ahead.
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.
Can we live at home while it is built?
Most families stay at home during a double-storey extension. The new structure is built outside first, and we only break through into the existing rooms near the end, usually one floor at a time. Upstairs, this may mean a bedroom is out of use for a week or two. We fit dust screens, protect floors and stairs, and plan any time without water or power in advance.
Is a double-storey extension better value than single-storey?
A double-storey extension usually gives better value per square metre than a single-storey one, because the same foundations and roof serve twice the floor area. The overall cost is higher, and planning can be harder because of the effect on neighbours. If you might want an extra bedroom later, building both floors now avoids a second round of disruption and scaffolding.
Near Daventry
We cover every part of Daventry, including NN11, and nearby Rugby, Northampton and Leamington Spa. Wherever you are within that patch, the survey is free and the quote comes to you in writing.