Double-storey extensions across Daventry
Our design and build teams take on double-storey extensions in Daventry, from the first measured survey through planning and building control to the finished room.
- Guide price in DaventryFrom £36,000 inc VAT
- PlanningUsually a householder application
- Build time16–24 weeks on site
- Postcode districtsNN11
Planning rules that apply in Daventry
In England a two-storey rear extension is permitted development only if it projects no more than 3 m from the original rear wall, sits at least 7 m from the rear boundary, matches the roof pitch and uses obscure, non-opening side windows upstairs. Most two-storey extensions therefore go through a householder planning application, which costs £548 from 1 April 2026 and normally takes about 8 weeks.
Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
Applications are decided by the local planning authority (your district, borough or unitary council).
What should I budget for a double-storey extension in Daventry?
For Daventry we adjust our national guide rates by ×0.95, the factor we use for East Midlands. Figures include VAT; your written quote after the survey replaces them.
Typical rates in Daventry: £1,470 to £2,850 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m, two floors 24 m² | £36,000 – £43,500 | £41,000 – £54,000 | £52,000 – £68,500 |
| 4 m × 4 m, two floors 32 m² | £47,000 – £56,500 | £54,500 – £71,500 | £69,500 – £91,500 |
| 4 m × 6 m, two floors 48 m² | £70,500 – £84,500 | £82,000 – £107,500 | £104,500 – £137,000 |
Try the guide-price tool to see a range for your own size and finish.
Who a double-storey extension suits
- Growing families who need a bedroom as well as a bigger kitchen
- Houses with enough distance to the rear or side boundary
- Homeowners who would otherwise consider moving
Working in Daventry
We cover Daventry and the postcode districts NN11. Nearby, we also take on projects in Towcester (11 miles), Northampton (12 miles), Brackley (16 miles), Market Harborough (18 miles).
For homes towards Warwickshire, Rugby is around 9 miles away. Homes across the East Midlands often have usable side land or a driveway beside the house, which opens up side and wraparound options.
Our process, step by step
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
Once the layout is agreed, we deal with the council: planning permission or written confirmation that none is needed, plus building control.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Questions people ask about double-storey extensions
Do I need building regulations approval in Daventry?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Who do I contract with for a double-storey extension in Daventry?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
Will my neighbours in Daventry be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
Do I need a Party Wall Agreement?
If you are in England or Wales and the work involves a shared wall or digging foundations close to a neighbour, the Party Wall etc. Act 1996 applies and notices must be served before work starts. We tell you which notices are needed.
Is a two-storey extension cheaper per square metre?
Usually. Our guide range is about £1,470 to £2,850 per m² of new floor area including VAT, compared with £1,660 to £3,230 per m² for single-storey work, because the foundations and roof are shared across two floors.
Book a free site visit in Daventry
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.