Extra bedroom and en-suite extensions in Durham
We cover Durham and the rest of County Durham for extra bedroom and en-suite extensions. Start with a free site visit and a plain-English view of what your house and plot can take.
Durham: the key facts for this kind of project.
- Postcode districts
- DH1
- County / area
- County Durham, England
- Price region
- North East England
- Guide price
- £50,500–£68,000 (£1,800–£2,430 per m²), plus £5,500–£11,000 for the en-suite
- Approval route
- It may be permitted development if it goes no more than 3 m beyond the original rear wall (counting any single-storey part) and stays 7 m from the rear boundary; otherwise it needs planning permission.
- Nearest towns
- Brandon (2.5 miles), Spennymoor (5.5 miles), Chester-le-Street (5.7 miles)
- Distance to Darlington
- about 17.5 miles
- First visit
- Free, no obligation
About an extra bedroom and en-suite extension
This service suits you if you need another bedroom, or want a main bedroom with its own bathroom, without converting the loft or moving. You get a first-floor layout that connects well to your landing, an en-suite designed for plumbing and ventilation, a useful room downstairs, the approvals your nation needs and the build, managed by us and carried out by vetted teams working under S&K.
We cover postcode district DH1 in and around Durham, along with neighbouring Brandon, Spennymoor and Chester-le-Street.
What it costs in Durham
Most of the cost of an extra bedroom and en-suite extension is set by its size and specification. For Durham and the rest of North East England, our guide is £1,800–£2,430 per m² including VAT, so about £50,500–£68,000 (plus £5,500–£11,000 for the en-suite) for a 4 m × 3.5 m footprint on two floors (28 m² of new floor space). Design fees, structural calculations and approval fees are separate and listed on our prices page.
| Spec | Per m² | A 4 m × 3.5 m footprint on two floors (28 m² of new floor space) |
|---|---|---|
| Essential | £1,660–£2,240 per m² | £46,500–£62,500 |
| Standard | £1,800–£2,430 per m² | £50,500–£68,000 |
| Premium | £2,160–£2,920 per m² | £60,500–£81,500 |
Planning and building regulations in Durham
In England, an extra bedroom extension at the rear can be permitted development if it goes no more than 3 m beyond the original rear wall and stays 7 m from the rear boundary. Upper side windows, including en-suite windows, must be obscure-glazed and non-opening below 1.7 m. Side or deeper designs need planning permission, costing £548 (or £575 for applications made from 8 December 2026).
Approval in England: Householder planning application: £548 (or £575 for applications made from 8 December 2026). Lawful development certificate: £274 (about £288 for applications from 8 December 2026). Councils should decide householder applications within 8 weeks of validation.
Building regulations: Building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end.
Design points for Durham homes
Planning the en-suite
An en-suite needs a route for the soil pipe to the drains, enough fall for waste water and an extract fan to the outside under Part F. Placing it over the ground-floor utility or near an existing drain keeps pipework short and hidden.
Connecting to the landing
The new bedroom must be reached from the existing landing, usually through a new opening in the outside wall or by taking part of an existing bedroom as a corridor. We look at the stairs and landing first, because a poor connection can waste much of the new space.
How we'd run your project
Free site visit
We visit your home in Durham, look at the structure, access and boundaries, and talk through what you want the new rooms to do.
Drawings, then consent
We draw the scheme, check it against the rules in England, and take it through the right consent with the council.
Engineer it
Foundations sized for two floors, steels for any openings, and building control approval, all before anyone starts on site.
Finish and certify
Second fix, plastering and making good, then building control's final inspection and the completion paperwork.
Questions about extra bedroom and en-suite extensions in Durham
Which postcodes do you cover around Durham?
We cover Durham (DH1) and nearby places including Brandon, Spennymoor and Chester-le-Street, plus the rest of County Durham. The first site visit is free.
Who handles building regulations for a project in Durham?
We handle it as part of the project. What's needed in England: building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end. We prepare the drawings and the engineer's calculations, book the inspections and pass you the completion paperwork at the end.
How long does an extra bedroom and en-suite extension take?
Allow 4 to 8 weeks for survey and design, then the approval period (councils should decide householder applications within 8 weeks of validation), then 4 to 8 weeks of technical design, which can overlap. The build itself usually takes 14 to 20 weeks, longer for large or complex designs.
Can an en-suite go in a room with no window?
Yes. A shower room without a window is allowed, provided it has a mechanical extract fan to the outside that meets Part F. Many people prefer a window for daylight, but if it faces a neighbour it will usually need obscure glass. We plan the extract route early so the duct is hidden.
What goes on the ground floor below a new bedroom?
Whatever suits you: a bigger kitchen, a family room, a study, a utility or a downstairs shower room. The ground floor usually costs about the same whatever it is used for, apart from kitchen units and bathroom fittings, which are priced separately.
Nearby
Close to Durham? We work across the area, including:
Other extensions in Durham
All two-storey extension services in Durham · Extra bedroom and en-suite extensions across County Durham
Book a free site visit in Durham and we'll tell you what's possible, what approvals you need and what the design stage would cost.