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.
Thinking about a single-storey extension in Kirkby? We take charge of the whole project, co-ordinating every trade involved, and one person keeps you updated. Guide prices for the North West sit at £33,000–£71,000 including VAT, and a typical job takes 10–16 weeks on site. Your own figure depends on what the survey finds and the specification you settle on.
- Guide price
- £33,000–£71,000 inc VAT
- Time on site
- 10–16 weeks on site
- Postcodes
- L32 and L33
- Planning rules
- England
- Local area
- Knowsley
- Survey
- Free, with a written quote
How much does a single-storey extension cost in Kirkby?
Budgeting for a single-storey extension in Kirkby? The numbers below include VAT and are adjusted for the North West, where costs are about 5% below the national guide. The headline range is £33,000–£71,000. Nothing is final until we have measured up at a free survey and agreed the specification with you.
| Type of job | What it usually involves | Guide in Kirkby |
|---|---|---|
| Small extension (8–12m²) | A modest rear or side extension, such as a utility room or a slightly larger kitchen. | £21,000–£38,000 |
| Typical rear extension (15–25m²) | A kitchen-diner or family room with bifold doors and a rooflight or lantern. | £33,000–£71,000 |
| Large or wrap-around (30m² plus) | A wrap-around or wide rear extension, often with structural steelwork into the house. | £66,000–£124,000 |
Your price depends mostly on:
- Floor area, shape and number of corners
- Roof type, rooflights, lanterns and the amount of glazing
- Steelwork needed to open into the existing house
- Finishes, kitchen, flooring and heating specification
What’s included?
- Groundworks, foundations and below-ground drainage
- Flat or pitched roof, with rooflights or a lantern if specified
- Steel beams to open into the existing house
- Windows and external doors, including bifolds if chosen
- Plastering, screed floor and internal doors
- Building control inspections and completion certificate
Local housing and a single-storey extension
Liverpool's housing includes Georgian terraces near the centre, large areas of Victorian red-brick terraces, Edwardian semis in the suburbs and big interwar council estates. The Wirral has Victorian villas and interwar semis, Southport has Victorian villas and bungalows, and St Helens and Knowsley have post-war estates and newer housing.
Terraces suit loft rooms, kitchen extensions and repointing, and many need their roofs and windows renewed. Suburban semis commonly take side extensions, driveways and porches.
Knowing the typical building types in Merseyside helps, but a survey of your own home in Kirkby is what decides the right approach to a single-storey extension.
Do you need permission in Kirkby?
Which rules apply depends on where you live. For Kirkby, 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?
Free site survey
We arrange a free site survey on a date convenient to you. We measure up, look at the existing structure and access, and discuss your plans for a single-storey extension so the price reflects your home.
Quote in writing
You get the price in writing, itemised so you can see where the money goes. As long as the specification stays the same, that is the price you pay for a single-storey extension.
Dates and permissions
Before anyone starts, we confirm the programme in writing, check whether consents are required and arrange deliveries. If a skip or scaffolding on the road needs a permit, we apply for it.
Finish and handover
Our trades complete a single-storey extension while your point of contact keeps you updated. When everything is finished, we clear the site, take away waste and go through the result with you before handover.
Why homeowners choose us
Common questions
Is a flat roof or a pitched roof better on an extension?
A flat roof is quicker to build and usually costs less, gives a clean modern look and works well with a roof lantern. A pitched roof matches the main house, sheds water faster and allows a vaulted ceiling, but it costs more and its height can affect neighbours. Modern flat roofs in EPDM rubber or GRP last well when properly detailed. Planning rules on height can also decide the choice.
What is the Party Wall Act and does it apply to me?
The Party Wall etc. Act 1996 applies in England and Wales only. In England and Wales, it requires you to give notice to neighbours before certain work on or near a shared wall, such as digging foundations within 3m of their building and deeper than its footings. Neighbours can agree or appoint a surveyor. Scotland and Northern Ireland have no equivalent Act, though general rights still apply. We identify whether notices are needed during the survey.
Can you combine a single-storey extension with other work?
Yes. Because we manage several trades under one contract, we can plan a single-storey extension alongside other work on your Kirkby home, such as new windows with rendering, or a kitchen refit with an extension. Combining jobs can reduce repeat set-up such as scaffolding, skips and access, and every element is listed and priced in the same written quote.
How long does a single-storey extension take to build?
A single-storey extension usually takes 10–16 weeks on site, from digging foundations to final plastering. Bad weather, deep foundations or a complex roof can add time. Before work starts, allow several weeks for drawings, structural calculations and building control approval, and longer if planning permission is needed. We give you a stage-by-stage programme with your quote so you know what happens each week.
Who do I deal with during the job?
One point of contact manages your project from survey to handover. They schedule the trades working under our contract, keep you updated on progress, and are the person to call with any question. You don't need to coordinate builders, electricians or decorators separately, because that is part of what we do.
Nearby towns
Whether you're in the centre of Kirkby or on its outskirts, L32 and L33 addresses are covered. We extend the same service, and the same fixed-price approach, to Norris Green, Maghull and Litherland.

