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.
If you have a single-storey extension on your list for a property in Billericay, we can help from the first measurements to the final clean-up. For a typical home, plan for 10–16 weeks on site, though larger or more complex jobs take longer. We cover postcodes CM12 and nearby Basildon, Wickford and Brentwood, and every quote we send is fixed for the scope described in it.
- Guide price
- £37,000–£79,000 inc VAT
- Time on site
- 10–16 weeks on site
- Postcodes
- CM12
- Planning rules
- England
- Local area
- Essex
- Survey
- Free, with a written quote
What should you budget for a single-storey extension in Billericay?
Every figure below is a guide for a single-storey extension in Billericay, inclusive of VAT. Regional pricing for the East of England works out about 5% above the national guide, and the overall span is £37,000–£79,000. The survey costs you nothing, and after it we commit to a firm price for your specification in writing.
| Type of job | What it usually involves | Guide in Billericay |
|---|---|---|
| Small extension (8–12m²) | A modest rear or side extension, such as a utility room or a slightly larger kitchen. | £23,000–£42,000 |
| Typical rear extension (15–25m²) | A kitchen-diner or family room with bifold doors and a rooflight or lantern. | £37,000–£79,000 |
| Large or wrap-around (30m² plus) | A wrap-around or wide rear extension, often with structural steelwork into the house. | £74,000–£136,000 |
The main things that change the figure:
- Floor area, shape and number of corners
- Ground conditions, foundation depth and drains to divert
- Steelwork needed to open into the existing house
- Finishes, kitchen, flooring and heating specification
What do you get?
- Groundworks, foundations and below-ground drainage
- Cavity walls built and insulated to building regulations
- 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
Homes in Essex
Essex ranges from timber-framed and weatherboarded cottages in the north, some with decorative pargeting, to Victorian terraces in Colchester, Chelmsford and Southend. Basildon and Harlow were built as post-war new towns, much of the south-east has interwar suburbs and bungalows, and large new estates continue to appear around Chelmsford and Braintree.
Essex is one of the driest counties in England, and London Clay in the south shrinks in dry spells, so trees and foundation depth matter.
Building traditions across Essex also raise conservation and planning questions, so we check those for a single-storey extension in Billericay at the survey stage.
Planning and building rules in Billericay
Homes in Billericay come under the regulations for England, summarised below. We don't rely on general rules alone: we confirm the position for your address with the council before a quote goes out.
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.
What happens after you get in touch?
A visit to your home
It starts with a survey at the property, free of charge. We check condition, access and services, ask how you want the finished result to look, and answer any questions you have about a single-storey extension.
Written quote
We put everything into a written, fixed-price quote: the specification, what's excluded, staged payments and the expected time on site. Take whatever time you need to decide; there's no pressure to commit.
Plan and prepare
Preparation matters as much as the build. We agree access, parking and working hours with you, order materials in good time, and confirm any permissions so the job isn't held up once it starts.
Finish and handover
Work goes ahead as scheduled and you deal with one contact throughout. When the last trade leaves, we clear and clean the site, talk you through what has been done and pass on any certificates and care instructions.
How we work
Frequently asked questions
Can we stay at home during the build?
Most people stay at home while we build a single-storey extension, because the new structure goes up outside before we break through. The disruptive part is usually the last few weeks, when we open into the house and fit the kitchen. We put up dust screens, keep a safe route through the house and agree a temporary kitchen setup if needed. Water and power are only off for short, planned periods.
Can I stay at home during the work?
In most cases, yes. Most people can live at home throughout, and we plan the work to keep disruption down by protecting floors, agreeing working hours and keeping access routes clear. Bigger jobs affecting kitchens, bathrooms or heating may mean a short spell with reduced facilities, and we talk this through with you at the survey.
How much does a single-storey extension cost?
A typical single-storey rear extension of 15–25m² costs £37,000–£79,000, built to a plastered finish ready for your kitchen and decoration. As a guide, allow roughly £1,600–£2,800 per square metre plus fixed costs for groundworks, steelwork and fees. Smaller extensions cost more per square metre. The kitchen, flooring and large glazed doors are usually the biggest extras. We confirm a fixed price for the agreed specification after the survey.
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.
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 Billericay 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.
Near Billericay
Coverage for Billericay spans CM12. Close by, Basildon, Wickford and Brentwood are covered too, and the rest of our UK-wide area follows the same survey-then-quote process from start to finish.