Knottingley, West Yorkshire
Semi-detached rear extension in Knottingley
We plan and build rear extensions for semi-detached houses for homeowners in Knottingley. Single or two-storey extensions for semi-detached houses, with side access and one party wall. Start with a free site visit, then a written price once the design is agreed.
Knottingley and its postcode districts WF8, WF10 and WF11 are part of our West Yorkshire coverage. 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 Knottingley?
For Knottingley we work from the Yorkshire and the Humber rate: £1,770–£2,880 per square metre of new floor, including VAT, standard specification. 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 |
Ground conditions, glazing, the roof and how far the house is opened up move the final figure within the range.
Do you need planning permission for a semi-detached rear extension in Knottingley?
Here is how the rules in England apply to a semi-detached rear extension in Knottingley.
English permitted development (Class A) allows a single-storey rear extension of 3 metres on a terraced or semi-detached house and 4 metres on a detached one, measured from the original house, with a maximum height of 4 metres and eaves of no more than 3 metres within 2 metres of a boundary.
England's rules allow a rear extension of more than one storey without an application only when it is no deeper than 3 metres and at least 7 metres from the boundary opposite the rear wall, and never on designated land. Most two-storey schemes need householder planning permission.
If 3 or 4 metres is not enough, England's prior approval route allows 6 metres on a terraced or semi-detached house and 8 metres on a detached house for a single-storey rear extension. Neighbours are consulted, the council decides within 42 days, and the fee is £249, rising to £310 from 8 December 2026.
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 Knottingley like to extend?
Stone terraces and brick semis are typical of Knottingley. 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 Knottingley comes together
Survey visit
We visit free of charge, measure up, check access, drainage and neighbours' extensions, and note what you want the room to do.
Design and guide price
Two or three layout options with a guide price for each, so you choose the design knowing what it costs.
Approvals
Permitted development check, prior approval or planning application, then Building Regulations drawings and structural calculations, plus party wall notices where they apply.
Fixed price and build
A written price for the agreed design, a start date and a named contact through the build, ending with the building control completion certificate.
Semi-detached rear extensions near Knottingley
From Knottingley, the nearest places we also cover are Pontefract (2.6 miles) and Castleford (4.5 miles).
- Semi-detached rear extension in Pontefract
- Semi-detached rear extension in Castleford
- Semi-detached rear extension in Featherstone
- Semi-detached rear extension in Kippax
- Semi-detached rear extension in Garforth
Other work in Knottingley:
FAQ
Semi-detached rear extension questions in Knottingley
Do I need planning permission for a rear extension in Knottingley?
Often not for a single-storey rear extension of up to 3 metres (4 metres on a detached house) under permitted development, or up to 6 or 8 metres with prior approval, unless the house is in a conservation area or its rights have been removed.
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.
Single or two-storey on a semi?
Two-storey if you need bedrooms, single-storey if you need a bigger kitchen. Planning risk is lower for single-storey.
Is the site visit in Knottingley free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.
What postcode areas do you cover around Knottingley?
Including WF8, WF10 and WF11, and the surrounding West Yorkshire area.
Can you match the brick or stone on my Knottingley house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.