Great Harwood, Lancashire
Semi-detached rear extension in Great Harwood
Single or two-storey extensions for semi-detached houses, with side access and one party wall. We design, get the approvals for and build rear extensions for semi-detached houses in Great Harwood and the surrounding area, with one contract from the first survey to building control sign-off.
Great Harwood is covered from our Lancashire round, including BB5 and BB6. Semi-detached houses are common across Lancashire, 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 Great Harwood?
Guide prices for a semi-detached rear extension in Great Harwood start from our North West England rate of £1,790–£2,910 per square metre, including VAT. North West prices sit below our West Midlands baseline; access on terraced streets is the main variable.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £21,500–£35,000 |
| 4 m wide × 5 m deep (20 m²) | £35,500–£58,500 |
| 4 m wide × 6 m deep (24 m²) | £43,000–£70,000 |
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 Great Harwood?
Here is how the rules in England apply to a semi-detached rear extension in Great Harwood.
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.
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. At the first visit we measure what is there now and tell you which route fits: permitted development, prior approval or a planning application.
What are homes in Great Harwood like to extend?
Great Harwood has long runs of terraced houses with back yards and alleys, plus 1930s semis further out. Yard extensions on terraces are often single-storey and close to both boundaries.
How a semi-detached rear extension in Great Harwood 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.
Paperwork handled
Planning, prior approval or permitted development, Building Regulations approval, structural design and party wall notices are all handled by us.
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 Great Harwood
From Great Harwood, the nearest places we also cover are Accrington (3.0 miles) and Blackburn (3.9 miles).
- Semi-detached rear extension in Accrington
- Semi-detached rear extension in Blackburn
- Semi-detached rear extension in Padiham
- Semi-detached rear extension in Clitheroe
- Semi-detached rear extension in Darwen
Other work in Great Harwood:
FAQ
Semi-detached rear extension questions in Great Harwood
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.
Do you handle building control in Great Harwood?
Yes. We apply to the council or a registered building control approver and hand over the completion certificate.
Do I need a party wall agreement?
Usually with the attached neighbour, in England and Wales.
Can you match the brick or stone on my Great Harwood house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
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.
How long does a rear extension take to build in Great Harwood?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.