Mirfield, West Yorkshire
Semi-detached rear extension in Mirfield
For homes in Mirfield, a semi-detached rear extension is often the simplest way to gain space without moving. Single or two-storey extensions for semi-detached houses, with side access and one party wall. We take it from survey to completion certificate.
Mirfield sits in West Yorkshire, with postcode districts including WF14. Semi-detached houses are common across West Yorkshire, and their side access makes rear extensions quicker to build.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a semi-detached rear extension cost in Mirfield?
A semi-detached rear extension in Mirfield is priced at £1,770–£2,880 per square metre including VAT as a guide, before kitchen fit-out and fees. Yorkshire prices sit below our West Midlands baseline; matching natural stone is the main variable.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £21,000–£34,500 |
| 4 m wide × 5 m deep (20 m²) | £35,500–£57,500 |
| 4 m wide × 6 m deep (24 m²) | £42,500–£69,000 |
We put a fixed price in writing once the design is agreed, and explain any provisional sums such as foundations.
Do you need planning permission for a semi-detached rear extension in Mirfield?
The planning route for a semi-detached rear extension in Mirfield is set by England's householder rules and your council.
In England a single-storey rear extension can often be built under permitted development: up to 3 metres beyond the original rear wall of an attached house, or 4 metres on a detached house, no higher than 4 metres, with eaves no higher than 3 metres if any part is within 2 metres of a boundary.
A two-storey rear extension can be permitted development in England only if it projects no more than 3 metres, stays at least 7 metres from the rear boundary, matches the existing roof pitch and has obscure-glazed upper side windows. In practice most double-storey rear extensions go through a householder planning application.
England also has the larger home extension route: a single-storey rear extension of up to 6 metres on an attached house or 8 metres on a detached house, after prior approval from the council. The council notifies your neighbours and has 42 days to decide; the fee is £249 (£310 for applications made from 8 December 2026). The route is not available on designated land such as conservation areas.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. We check your house's planning history and any conservation area before drawing, so the route is clear before you spend on plans.
What are homes in Mirfield like to extend?
Stone terraces and brick semis are typical of Mirfield. Matching sandstone or gritstone on a terrace is one of the biggest cost variables, and reclaimed stone is often the best match.
How a semi-detached rear extension in Mirfield comes together
Free site visit
We measure the house and garden, look at the back wall, drainage and boundaries, and talk through what you want from the space.
Design and guide price
Two or three layout options with a guide price for each, so you choose the design knowing what it costs.
Planning and regulations
We take the design through the right planning route, then produce the construction drawings and engineer's calculations for building control.
Build and sign-off
We build to the approved drawings with regular updates, then hand over the building control completion certificate and any guarantees from suppliers.
Semi-detached rear extensions near Mirfield
From Mirfield, the nearest places we also cover are Liversedge (2.2 miles) and Heckmondwike (2.4 miles).
- Semi-detached rear extension in Liversedge
- Semi-detached rear extension in Heckmondwike
- Semi-detached rear extension in Dewsbury
- Semi-detached rear extension in Batley
- Semi-detached rear extension in Cleckheaton
Other work in Mirfield:
FAQ
Semi-detached rear extension questions in Mirfield
Will I need a structural engineer?
Yes for the beam over the new opening and usually the foundations; we arrange them and their calculations go to building control.
How much does a semi-detached rear extension cost in Mirfield?
As a guide, £1,770–£2,880 per square metre including VAT for a standard specification. For example, 3 m wide × 4 m deep (12 m²): about £21,000–£34,500 at that rate. Your written price follows the survey.
Can I match pebbledash or render?
Yes. Many semis are refinished with new render across the whole back elevation so old and new match.
Can I get a price without a visit?
Our online guide-price tool gives a range in a couple of minutes. A written price needs a survey.
Who will build my extension?
Vetted building teams working under contract to us. Your contract is with S&K Property Investments and Improvement Ltd for the design and the build.
Do I need a party wall agreement?
In England, usually yes if the extension is on or near a shared boundary or the foundations are close to a neighbour's building. We serve the notices.