Single Storey Extensions in Winslow | Building Control Handled

A single storey extension in Winslow typically costs £2,400–£3,200 per m² finished ready for decoration — roughly £29,000–£38,500 for a 12m² rear extension, with any kitchen fit-out priced separately. An extension in Winslow needs building regulations approval — Buckinghamshire Council does not publish fixed building control fees; it quotes for each project, so you request a building control quote for the extension. It either fits within permitted development or needs householder planning permission, which costs £548 from April 2026 and is decided within eight weeks.

Typical cost: £2,400–£3,200 per m²
Council: Buckinghamshire Council
Planning: Permitted development or £548 application
Building regulations: Needed
Ground: Sand, gravel and clay in pockets

Prices are our 2026 guide prices; your fixed price comes in writing after the free visit. Council fees checked October 2026.

Extensions in Winslow

Extensions on Winslow houses

Winslow is a brick town: its conservation area appraisal, adopted in April 2026, notes that red brick — mostly in Flemish bond — is prevalent, with render, timber frame, clay tile and some thatch. The core around Market Square, High Street, Sheep Street and Horn Street fronts the pavement, the Victorian and Edwardian streets to the north have front gardens, and modern estates sit around the edge.

Most extensions we build here are single storey at the rear, matched to the existing brick or stone, with the drainage and any sewer nearby checked before the footings are dug.

We cover Winslow (MK18) and the areas around it, including Great Horwood, Little Horwood, Swanbourne, Granborough, Addington, Shipton, East Claydon and Mursley. Travel does not change the price.

Winslow specifically

Ground, drainage and conservation in Winslow

The British Geological Survey notes that glacial sand and gravel are widespread around Winslow, alongside clay till and Oxford Clay, so ground can change within a few metres. Sub-base depth and drainage are set from what we find on the day. Because the ground varies, the foundation depth is confirmed from the trial holes and agreed with building control on site.

Winslow Conservation Area was re-appraised in April 2026 with a revised boundary. There is no Article 4 direction at present, though the appraisal recommends one be considered, and it discourages close-boarded fencing on streets such as Station Road and Avenue Road in favour of traditional boundaries.

Sources: Winslow Conservation Area appraisal (2026).

Buckinghamshire Council

Planning, building regulations and fees in Winslow

Step 1Check whether it fits permitted development, and if you want certainty apply for a lawful development certificate (£274). Planning Portal: extensions
Step 2In the Winslow conservation area, side extensions and rear extensions of more than one storey always need planning permission.
Step 3If permission is needed, apply for householder planning permission (£548 from April 2026), decided within eight weeks. Pre-application advice from Buckinghamshire Council costs £579.40 including VAT, for an initial meeting and a written reply. Planning Portal: application fees
Step 4Apply for building regulations approval: Buckinghamshire Council does not publish fixed building control fees; it quotes for each project, so you request a building control quote for the extension. Buckinghamshire Council: building control fees
Step 5We build to the approved drawings and work to the building control inspections at each stage.

Council fees and rules checked October 2026. Planning fees are the national fees from 1 April 2026.

What is included

Everything below is included in an extension

Drawings and the building control application
Foundations set from a trial hole, not a guess
Drainage diverted or rebuilt where it needs to be
Build-over and party wall matters flagged and handled
Roof and threshold junctions detailed properly
Electrics and plumbing by registered trades, with certificates
Building control sign-off at the end
A five year guarantee, in writing

Questions

Extensions in Winslow: questions

How much does a single storey extension cost in Winslow?

A single storey extension in Winslow typically costs £2,400–£3,200 per m² finished ready for decoration — roughly £29,000–£38,500 for a 12m² rear extension, with any kitchen fit-out priced separately. Your fixed price comes in writing after the free visit.

How much does planning and building control cost for an extension in Winslow?

Householder planning permission is £548 (from April 2026) if you need it, or £274 for a lawful development certificate. Buckinghamshire Council does not publish fixed building control fees; it quotes for each project, so you request a building control quote for the extension.

Do I need planning permission for an extension in Winslow?

Many single-storey rear extensions are permitted development within size limits. In the Winslow conservation area, side extensions and rear extensions of more than one storey always need permission.

Is Winslow in a conservation area?