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House Extensions in Milton Keynes2026-10-15T13:53:42+00:00

House Extensions in Milton Keynes

House extensions in Milton Keynes, designed and built by our own in-house team. Planning handled. One fixed price.

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Local Extension Builders

Extension Builders for Every Kind of Milton Keynes Home

Milton Keynes was designated a new town in 1967, so it holds a wider mix of housing than most places. Estate homes from the 1970s and 1980s sit a short drive from Victorian terraces in Wolverton and stone cottages in Hanslope, and each one raises different questions before an extension is designed.

We design and build house extensions across Milton Keynes with our own directly employed team. We manage planning and building control for you, and every quote is fixed before work starts. See every option on our page covering the types of extension we build.

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Two-storey side extension on a Victorian brick house in Stony Stratford, Milton Keynes

How It Works

How an Extension Project in Milton Keynes Works, From First Visit to Handover

STEP ONE

Site Visit and Brief

We measure up, discuss what you need and your budget, and check your home’s planning history and permitted development position.

STEP TWO

Design and Drawings

Our design and build service produces planning and Building Regulations drawings, with structural engineering coordinated by us.

STEP THREE

Fixed-Price Quote

An itemised price based on measured quantities. No provisional sums and no headline figure that grows once work starts.

STEP FOUR

Planning and Building Control

Where an application is needed, we submit it to Milton Keynes City Council and manage it to a decision, typically 8 to 12 weeks.

STEP FIVE

The Build

Our own site team carries out the work. Single-storey extensions take 10 to 16 weeks on site, double-storey 16 to 24 weeks.

STEP SIX

Handover

Snagging and building control sign-off before the project closes. Most projects take 6 to 12 months from first conversation to completion.

Case Study

Stone Extension and Whole-House Upgrade, Castlethorpe

A stone home in Castlethorpe gained two stone extensions, a fifth bedroom and a kitchen-diner with corner bifold doors on a concealed steel. Neighbour and massing constraints on a newer development were resolved by pulling back the first-floor footprint and allocating a parking space.

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Read Full Case Study
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Homes We Extend

What Kind of Extension Suits Your Milton Keynes Home?

Estate Homes From the 1970s and 1980s

Rear kitchen-diners and side extensions on corner plots. We check how the house was built first, as some estates such as Netherfield used timber frame systems.

Newer Estates Built Since 2000

Rear and two-storey side extensions. The first question is whether permitted development rights were removed when the estate was approved.

Victorian and Edwardian Homes

Side return and rear kitchen extensions in Bletchley, Wolverton and Stony Stratford, where conservation area status and a close brick match matter.

Stone Village Homes

Matching stone extensions in Castlethorpe, Hanslope and Olney, often over two storeys and shaped by conservation area rules.

Kitchen-Diner Extensions

The most requested extension in Milton Keynes: a single-storey rear addition with bifold doors, rooflights and underfloor heating. Many fall within permitted development.

Two-Storey Extensions

Bedrooms and living space in one build, usually at a lower cost per square metre. These almost always need a planning application, which we manage.

Pricing and Budgets

How Much Does a House Extension Cost in Milton Keynes?

Based on current Cognitive Construction pricing, a single-storey extension typically costs £1,800 to £2,800 per square metre to build, depending on specification. Professional fees, VAT and any structural work to the existing house are on top, and all figures are subject to a site survey.

You’ll get an itemised, fixed-price quote before you commit.

Get a fixed-price quote

Single-storey extension

£1,800 to £2,800 per m²

Build cost per square metre at a standard specification, before fees and VAT.

Example: 20 m² rear extension

£36,000 to £56,000

Roughly 4 by 5 metres, a typical kitchen-diner extension, before fees and VAT.

Double-storey extension

Lower per m²

Foundations, walls and roof serve both floors, so the cost per square metre is lower. Priced after survey.

Scope What it covers Indicative figure
Single-storey extension Build cost per square metre at a standard specification, before fees and VAT £1,800 to £2,800 per m²
Example: 20 m² rear extension Roughly 4 by 5 metres, a typical kitchen-diner extension, before fees and VAT £36,000 to £56,000
Double-storey extension Foundations, walls and roof serve both floors, so the cost per square metre is lower Priced after survey

Planning Permission

Do You Need Planning Permission for an Extension in Milton Keynes?

Not always. Many single-storey rear extensions fall under permitted development. Two local factors change that, and we check both at the first visit.

  • Permitted development limits. Up to 4 metres deep on a detached house or 3 metres on other houses, rising to 8 and 6 metres under the larger home extension scheme.
  • Conservation areas. Milton Keynes has 27 conservation areas, including Bletchley, Olney, Stony Stratford and Wolverton, where side and two-storey rear extensions need planning permission.
  • Newer estates. The estate’s original planning permission can remove permitted development rights, so a full application is needed.
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Extension Builders in Milton Keynes

Why Choose Us as Your Extension Builders in Milton Keynes

Our office is in MK18, so site visits, progress checks and snagging fit around you. Our trades are employed directly, and the same people see your extension through from day one to handover.

  • Our own team: groundworks, brickwork, carpentry, plumbing and electrics
  • Clear pricing: itemised quotes based on measured quantities
  • Planning handled: applications, structural input and building control
  • Local knowledge: estate planning conditions, conservation areas and brick matching
  • Federation of Master Builders approved, backed by our 10 Point Guarantee

Client Testimonials
Our Accreditations

Common Questions

Milton Keynes Extension FAQs

How much does a house extension cost in Milton Keynes?2026-10-15T09:00:00+00:00

Based on current Cognitive Construction pricing, a single-storey extension typically costs £1,800 to £2,800 per square metre to build, before fees and VAT. We confirm a fixed price after a site survey.

Can I extend my home on a newer Milton Keynes estate without planning permission?2026-10-15T09:01:00+00:00

Sometimes. If the original planning permission removed permitted development rights, you’ll need a full application, so we check your estate’s planning history before any design work starts.

Do you build extensions in Milton Keynes conservation areas?2026-10-15T09:02:00+00:00

Yes. We match brick, stone and detailing to the existing house and prepare the information the council needs to assess an application in a conservation area.

Do I need drawings before you can quote for my extension?2026-10-15T09:03:00+00:00

No. We visit, take your brief and produce the drawings through our design and build team, so one team takes you from first visit to handover.

Federation of Master Builders

Our 10-point quality guarantee

Fair pricing, qualified tradespeople, quality checks at every stage. Backed by our director personally.

Download Our Guarantee

Service Areas

Areas We Cover in Milton Keynes

We build extensions across the city and its surrounding towns and villages, including:

  • Central Milton Keynes

  • Bletchley

  • Stony Stratford

  • Newport Pagnell
  • Woburn Sands

  • New Bradwell
  • Wolverton

  • Olney
  • Water Eaton
  • Shenley and Loughton
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Get In Touch

Get a Quote for Your Milton Keynes Extension

Tell us what you’d like to build and we’ll arrange a visit to talk through what your home allows, the likely cost and a realistic timescale.

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