Extensions in Horwich: design, planning and build
Every type of house extension in Horwich, from single-storey kitchen extensions to two-storey additions, side returns and orangeries. We design, handle the approvals and build.
- Postcode districtsBL6
- Price regionNorth West England (×0.95)
- Planning rulesEngland
- Site visitFree, no obligation

Do extensions in Horwich need planning permission?
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 extension can be permitted development if it is no more than 4 m high and no wider than half the width of the original house. Two-storey side extensions, and any side extension on designated land such as a conservation area, need a householder planning application.
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.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
Applications are decided by the local planning authority (your district, borough or unitary council).
Guide prices for Horwich
Every figure below is a guide for Horwich, adjusted for North West England build costs (×0.95) and including VAT. Design and council fees are shown separately on each page.
| Extension type | Example size | Standard spec (inc VAT) |
|---|---|---|
| Kitchen extensions | 20 m² | £39,500 – £50,500 |
| Double-storey extensions | 32 m² | £54,500 – £71,500 |
| Single-storey rear extensions | 20 m² | £38,500 – £49,500 |
| Conservatory replacement extensions | 14 m² | £28,500 – £37,000 |
| Extensions over a garage | 12 m² | £23,500 – £31,000 |
| Orangery extensions | 16 m² | £42,500 – £53,500 |
Choosing the right extension in Horwich
The North West has a high share of Victorian and Edwardian terraces with rear yards and outriggers, plus large areas of inter-war semis in the suburbs.
For many houses here, kitchen extensions, side return extensions or double-storey extensions gives the most useful space for the budget.
Horwich and surrounding towns
Across BL6, we can visit, measure and advise. The same team covers Westhoughton (4 miles), Hindley (5 miles), Bolton (5 miles), Wigan (5 miles), Atherton (6 miles), all within easy reach. Just over the Lancashire border, Chorley is about 4 miles away.
Choose an extension type
- Utility and boot room extensions · from £13,000
- Side extensions · from £20,500
- Flat roof extensions · from £19,500
- Orangery extensions · from £28,500
- Double-storey extensions · from £36,000
- Extensions over a garage · from £22,500
- Side return extensions · from £17,000
- Extension plans and drawings · from £1,100
- Bedroom extensions · from £24,500
- Kitchen extensions · from £25,500
- Pitched roof extensions · from £21,000
- Porch extensions · from £3,800
- Bungalow extensions · from £24,500
- Single-storey rear extensions · from £19,500
- Glass box extensions · from £28,500
- Timber frame extensions · from £19,500
- Building regulations for extensions · from £850
- Wraparound extensions · from £34,000
- Planning permission for extensions · from £300
- Annexe extensions · from £52,000
- Conservatory replacement extensions · from £19,000
- Home office extensions · from £15,000
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
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Questions about extensions in Horwich
How much does an extension cost in Horwich?
Using our North West England factor (×0.95), a standard-spec single-storey extension of 20 m² is a guide £38,500 to £49,500 including VAT, and a 32 m² two-storey extension £54,500 to £71,500. Your written price follows the survey.
Will my neighbours need to be told?
If you apply for planning or prior approval the council notifies them, and in England party wall notices may be needed for work near a shared boundary.
Do you handle building regulations?
Yes. We prepare the drawings and calculations, submit them and book inspections, ending with a completion certificate.
Do I need planning permission for an extension in Horwich?
Not always. It depends on the size, position and your property's history. Many single-storey rear extensions in England are permitted development or can use prior approval.
Can I get a price before anyone visits?
Yes. This page shows guide prices adjusted for Horwich, and the guide-price tool gives a range for your own size and finish in about a minute.
Book a free site visit in Horwich
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.