Bedroom extensions in Washington: design, approvals and build
Thinking about a bedroom extension for your Washington home? Start with a free site visit: we measure up, check what the council will allow and give you honest guide figures on the day.
- Guide price in WashingtonFrom £23,500 inc VAT
- PlanningUsually a householder application
- Build time14–22 weeks on site
- Postcode districtsDH4, NE9, NE10, NE37, NE38
Bedroom extension prices in Washington
Labour and material costs vary across the UK, so for Washington we use our North East England factor (×0.91). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Washington: £1,460 to £2,910 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| One bedroom 12 m² | £23,500 – £29,000 | £23,500 – £31,000 | £26,000 – £35,000 |
| Bedroom and en-suite 18 m² | £26,000 – £32,000 | £31,000 – £40,500 | £39,000 – £52,500 |
| Two rooms 30 m² | £43,500 – £53,500 | £51,500 – £67,000 | £65,500 – £87,500 |
For a figure based on your own dimensions, use our guide-price tool.
Planning and approvals in Washington
In England a two-storey rear extension is permitted development only if it projects no more than 3 m from the original rear wall, sits at least 7 m from the rear boundary, matches the roof pitch and uses obscure, non-opening side windows upstairs. Most two-storey extensions therefore go through a householder planning application, which costs £548 from 1 April 2026 and normally takes about 8 weeks.
Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
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).
Extensions in and around Washington
Postcode districts we cover around Washington include DH4, NE9, NE10, NE37, NE38, SR4. Neighbouring towns we cover include Felling (4 miles), Houghton-le-Spring (5 miles), Hebburn (5 miles), Sunderland (5 miles).
Just over the County Durham border, Chester-le-Street is about 4 miles away. Across the North East, houses often have rear yards or modest gardens, so compact, well-lit single-storey extensions make the biggest difference.
What we take care of
- Structure, roof, insulation and finish
- Fire safety: escape windows and smoke alarms to building regulations
- Planning drawings and application
- Heating extended to the new rooms
- En-suite drainage and ventilation design
New bedrooms on an upper floor need an escape window or a protected route to the outside under the building regulations. We design the window sizes and stair route to meet that from the outset.
Our process, step by step
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
First, a site visit: we look at the house, garden, access and drains and listen to what you need.
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
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Common questions in Washington
Do you cover all of Washington?
Yes. We cover Washington and the surrounding parts of Tyne and Wear. Site visits are free and there is no obligation.
Who do I contract with for a bedroom extension in Washington?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
Do I need building regulations approval in Washington?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Can I add a ground-floor bedroom for a relative?
Yes. A ground-floor bedroom with an accessible shower room is a common request. If it will be lived in as a self-contained home, planning treats it differently, so tell us how it will be used.
Will a new bedroom need planning permission?
Upstairs additions usually do. Ground-floor rooms may fall within permitted development, depending on size and position.
Book a free site visit in Washington
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.