A single-storey extension is a new ground-floor room built onto your house, usually at the rear or side, with its own foundations, walls and roof, creating a bigger kitchen, living space or bedroom without moving home.
Whatever type of house you own in Washington, we start by looking at how a single-storey extension would fit it rather than offering a standard package. We cover NE37 and NE38 and neighbouring places such as Chester-le-Street, Felling and Houghton-Le-Spring. One named person looks after you from survey to handover, and nothing is booked until you hold our figure in writing, fixed for the work described.
- Guide price
- £31,500–£68,000 inc VAT
- Time on site
- 10–16 weeks on site
- Postcodes
- NE37 and NE38
- Planning rules
- England
- Local area
- Sunderland
- Survey
- Free, with a written quote
What should you budget for a single-storey extension in Washington?
These are guide costs, not quotes. For a single-storey extension in Washington the range is £31,500–£68,000, VAT included, reflecting prices in the North East that are about 10% below the national guide. Once we have visited for a free survey, you get a firm figure for the scope you approve.
| Type of job | What it usually involves | Guide in Washington |
|---|---|---|
| Small extension (8–12m²) | A modest rear or side extension, such as a utility room or a slightly larger kitchen. | £20,000–£36,000 |
| Typical rear extension (15–25m²) | A kitchen-diner or family room with bifold doors and a rooflight or lantern. | £31,500–£68,000 |
| Large or wrap-around (30m² plus) | A wrap-around or wide rear extension, often with structural steelwork into the house. | £63,000–£117,000 |
What moves the price up or down:
- Roof type, rooflights, lanterns and the amount of glazing
- Ground conditions, foundation depth and drains to divert
- Steelwork needed to open into the existing house
- Finishes, kitchen, flooring and heating specification
What’s included?
- Groundworks, foundations and below-ground drainage
- Cavity walls built and insulated to building regulations
- Flat or pitched roof, with rooflights or a lantern if specified
- Steel beams to open into the existing house
- Electrics and plumbing by qualified trades, with certificates
- Building control inspections and completion certificate
What are homes like around Washington?
Tyneside flats, pairs of upper and lower flats behind a terraced front, are a distinctive feature of Newcastle and Gateshead. Sunderland is known for its single-storey terraced 'Sunderland cottages', and both cities have Victorian brick and stone terraces, interwar estates and post-war housing. Washington was built as a new town from the 1960s.
Terraces and Tyneside flats commonly need repointing, roof work and window replacement. Houses suit loft rooms and rear extensions, and new-town homes often take garage conversions and cladding upgrades.
Whatever era your Washington home dates from, we plan a single-storey extension around how it is actually built rather than a one-size-fits-all specification.
Permissions for a single-storey extension in Washington
Which rules apply depends on where you live. For Washington, the answer is England, and the points below reflect that; we verify them with the council before quoting.
In England, many single-storey rear extensions are permitted development: typically up to 3 m deep on a semi-detached or terraced house and 4 m on a detached house, no more than 4 m high, and covering no more than half the land around the original house. Larger rear extensions can go through the prior approval process. Side extensions, flats, listed buildings, conservation areas and homes where permitted development rights have been removed need planning permission.
Building Regulations approval is needed for almost every extension, covering foundations, structure, insulation, drainage, ventilation and fire safety. If the work is on or near a shared wall or boundary, the Party Wall etc. Act 1996 may apply.
Rules change and every property is different, so we check the planning history and constraints for your address before we quote.
How does the job run?
We look at the job
A free survey comes first. It gives us what we need to price a single-storey extension properly, including dimensions, existing materials and access for deliveries, and gives you the chance to ask anything you like.
Your fixed price
After the survey we send a quote for a single-storey extension that fixes the price for the scope we've agreed. If you want to change materials or scope, we revise it in writing before anything is booked.
Plan and prepare
Once you accept, we agree start dates, order materials and deal with any planning, building control or neighbour notices the job needs. You'll know who is coming and when before work begins.
The work itself
On site, the agreed plan is followed and any change is put in writing first. At completion we do a final clean, go through the snagging list with you and leave you with the relevant documents.
What you can expect from us
Questions about a single-storey extension in Washington
What does a typical extension build look like week by week?
A typical single-storey extension follows the same order: clearing the site and digging foundations, building walls up to roof level, then fitting the roof and windows to make it weathertight. Electrics, plumbing, insulation and plastering follow. The last stage is opening into the house, laying the screed and fitting doors and finishes. Building control inspects at key stages, and we book those visits for you.
How much will a single-storey extension cost in Washington?
As a guide, expect to pay £31,500–£68,000 including VAT for a single-storey extension in Washington. That range is adjusted for the North East, which runs about 10% below the national guide. Where your project lands depends on size, materials, access and the condition of what is already there. We confirm a fixed price in writing after a free survey of your home.
Do you cover Chester-le-Street, Felling and Houghton-Le-Spring?
Yes. As well as Washington, we cover Chester-le-Street, Felling and Houghton-Le-Spring and the rest of Tyne and Wear. Our coverage is UK-wide, so the process is the same wherever you are: a free site survey, a quote in writing that fixes the price for the agreed scope, and one point of contact while the work is planned and carried out.
Do I need an architect for an extension?
You need proper drawings for an extension, but not always a full architect service. A designer or architectural technician can produce planning and building regulations drawings, and a structural engineer provides beam and foundation calculations. If you already have drawings, we price from them. If not, we can arrange the drawings and calculations as part of the project so everything is coordinated from the start.
Do I need planning permission for a single-storey extension?
Whether you need planning permission depends on the extension's size and height, how close it is to boundaries, your home's location, whether it is listed or in a conservation area, and which UK nation you live in. In England, many rear extensions up to 3m deep on a semi or terrace, or 4m on a detached house, can be built under permitted development. We check the rules that apply to your home before quoting.
Also covering areas around Washington
Washington and its NE37 and NE38 postcodes are part of our coverage. Homeowners in Chester-le-Street, Felling and Houghton-Le-Spring can also book a free survey with us and receive a written price for their job.