Extensions in Milton Keynes: design, planning and build
From a small utility to a two-storey addition, we take on house extensions throughout Milton Keynes, starting with a free visit and a planning check.
- Postcode districtsMK5, MK6, MK9, MK13, MK14, MK15
- Price regionSouth East England (×1.12)
- Planning rulesEngland
- Site visitFree, no obligation
Planning and building control in Milton Keynes
In England a single-storey rear extension can usually go up to 3 m beyond the original rear wall of a semi-detached or terraced house, or 4 m on a detached house, without a planning application, provided it is no more than 4 m high, keeps eaves to 3 m within 2 m of a boundary and, with other buildings, covers no more than half the land around the original house. The larger home extension prior approval scheme raises those depths to 6 m and 8 m, with neighbours notified and a 42-day decision.
In England a single-storey side return infill is often permitted development if it stays within the height limits and is no wider than half the width of the original house. Conservation areas, listed buildings and flats always need an application, and the boundary wall usually brings in the Party Wall Act.
In a conservation area, national park, National Landscape, the Broads or a World Heritage Site the permitted development limits are tighter (no side or two-storey extensions without an application). Listed homes need listed building consent, and if permitted development rights have been removed, any extension needs an application.
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.
Applications are decided by the local planning authority (your district, borough or unitary council).
Which extension suits a Milton Keynes home?
In the South East, plenty of houses have already been extended once, which makes checking the remaining permitted development allowance an important early step.
The types we would usually look at first for a home in Milton Keynes are wraparound extensions, double-storey extensions and single-storey rear extensions, depending on the garden and how the house is laid out.
Milton Keynes and surrounding towns
Across MK5, MK6, MK9, MK13, MK14, MK15, we can visit, measure and advise. Nearby, we also take on projects in Bletchley (3 miles), Aylesbury (16 miles), Chesham (25 miles), Amersham (27 miles), High Wycombe (29 miles). For homes towards Bedfordshire, Leighton Buzzard is around 10 miles away.
Popular extension prices in Milton Keynes
Use these Milton Keynes guide prices to sense-check a budget; the guide-price tool narrows them to your own size, and the site visit turns them into a written figure.
| Extension type | Example size | Standard spec (inc VAT) |
|---|---|---|
| Orangery extensions | 16 m² | £50,000 – £63,000 |
| Kitchen extensions | 20 m² | £47,000 – £59,500 |
| Wraparound extensions | 25 m² | £64,000 – £81,500 |
| Extensions over a garage | 12 m² | £28,000 – £36,500 |
| Double-storey extensions | 32 m² | £64,500 – £84,500 |
| Conservatory replacement extensions | 14 m² | £33,500 – £43,500 |
| Side return extensions | 11 m² | £29,500 – £37,000 |
All extension types we build in Milton Keynes
- Building regulations for extensions · from £1,000
- Pitched roof extensions · from £24,500
- Annexe extensions · from £61,500
- Glass box extensions · from £33,500
- Flat roof extensions · from £23,500
- Porch extensions · from £4,450
- Home office extensions · from £17,500
- Double-storey extensions · from £42,500
- Conservatory replacement extensions · from £22,000
- Orangery extensions · from £33,500
- Utility and boot room extensions · from £15,500
- Wraparound extensions · from £40,000
- Extension plans and drawings · from £1,300
- Bungalow extensions · from £29,000
- Kitchen extensions · from £30,000
- Side extensions · from £24,500
- Single-storey rear extensions · from £23,500
- Bedroom extensions · from £29,000
- Timber frame extensions · from £23,500
- Planning permission for extensions · from £350
- Extensions over a garage · from £26,500
- Side return extensions · from £20,000
Free site visit
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
We produce the drawings and structural design, and manage the approvals so they are in place before work starts.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Questions about extensions in Milton Keynes
How much does an extension cost in Milton Keynes?
Using our South East England factor (×1.12), a standard-spec single-storey extension of 20 m² is a guide £45,500 to £58,500 including VAT, and a 32 m² two-storey extension £64,500 to £84,500. Your written price follows the survey.
Do you handle building regulations?
Yes. We prepare the drawings and calculations, submit them and book inspections, ending with a completion certificate.
How long does an extension take in Milton Keynes?
Usually 2 to 4 months of design and approvals, then 10 to 16 weeks on site for a single-storey extension or 16 to 24 weeks for two storeys.
Can I get a price before anyone visits?
Yes. This page shows guide prices adjusted for Milton Keynes, and the guide-price tool gives a range for your own size and finish in about a minute.
Book a free site visit in Milton Keynes
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.