Two-storey wraparound extensions in Brentwood

The basics for Brentwood at a glance.

Postcode districts: CM13, CM14 and CM15
County / area: Essex, England
Price region: East of England
Guide price: £124,000–£170,000 (£2,210–£3,040 per m²)
Approval route: Planning permission is needed: the side part takes it outside permitted development in England.
Nearest towns: Harold Wood (3.6 miles), Emerson Park (4.5 miles), Billericay (4.9 miles)
Distance to Southend-on-Sea: about 18.5 miles
First visit: Free, no obligation

About a two-storey wraparound extension

A two-storey wraparound extension is an L-shaped addition that extends both the side and the rear of your house, on two floors. It gives one of the largest gains in floor space of any extension, typically a big open-plan kitchen and living area below and two or more bedrooms or bathrooms above. In England it needs planning permission, because the side part is more than one storey.

Around Brentwood we also work in Harold Wood, Emerson Park and Billericay, and across the rest of Essex. Postcode districts in and near Brentwood: CM13, CM14 and CM15.

What it costs in Brentwood

Expect a two-storey wraparound extension in Brentwood to land somewhere around £124,000–£170,000 for an L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space). Our East of England guide rate is £2,210–£3,040 per m², including VAT. Keep a contingency of around 10% for things nobody can see until the ground is opened up.

Spec	Per m²	An L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space)
Essential	£2,040–£2,800 per m²	£114,000–£156,500
Standard	£2,210–£3,040 per m²	£124,000–£170,000
Premium	£2,660–£3,650 per m²	£149,000–£204,000

Planning and building regulations in Brentwood

In England, a two-storey wraparound extension needs householder planning permission, because any extension beyond a side wall must be single storey to be permitted development. The application costs £548 (or £575 for applications made from 8 December 2026). Councils weigh the side part against the street scene and the rear part against neighbours' light and outlook, and should decide within 8 weeks of validation.

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 Brentwood homes

Two roofs that meet

A wraparound needs the side roof and rear roof to join cleanly, often with a valley or hip where they meet. Getting pitches and ridge heights right keeps rainwater moving and avoids a bulky mass at the back corner, which neighbours and planners notice.

The corner post

At the outside corner of the L, there is no existing wall to carry the floor above. Opening the ground floor fully usually means a steel frame or a corner post, and the engineer's design sets how slim it can be. We decide early whether you want a clear corner or a visible post.

How we'd run your project

Look at the house
We start in Brentwood with a free visit: measurements, photos, a look at the loft and drains, and a frank chat about budget.
Design and approvals
We draw the extension and check it against the rules for England, then apply for planning permission or a certificate of lawfulness, whichever fits.
Structure and building control
A structural engineer sizes the foundations and steels, and we get building regulations approval before work starts.
Build
Foundations, walls, floor, roof, windows, then first and second fix. We break through into the house as late as we can.

Questions about two-storey wraparound extensions in Brentwood

Do I need planning permission for a two-storey wraparound extension in Brentwood?

Brentwood is in England, so England planning rules apply. Planning permission is needed: the side part takes it outside permitted development in England. If in doubt, a lawful development certificate or a planning application gives you certainty before you build.

Which postcodes do you cover around Brentwood?

We cover Brentwood (CM13, CM14 and CM15) and nearby places including Harold Wood, Emerson Park and Billericay, plus the rest of Essex. The first site visit is free.

Who handles building regulations for a project in Brentwood?

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.

Is a wraparound extension better than separate side and rear extensions?

Building both at once usually costs less than two separate projects, because you pay for one set-up, one scaffold, one roof junction and one set of approvals. It also lets the layout be designed as a whole. The trade-off is a larger single outlay and a longer build, often 16 to 24 weeks at this size.

Does a wraparound extension need steel?

Almost always. Opening the corner of the house and the old rear wall to make one open-plan space means steel beams, and often a steel post or frame at the outside corner. The structural engineer sizes these, and the steel is ordered once the design is fixed, which is one reason a wraparound needs careful sequencing.

Nearby

The same service in neighbouring towns:

Other extensions in Brentwood

All two-storey extension services in Brentwood · Two-storey wraparound extensions across Essex

Tell us about your house in Brentwood and we'll call you back to arrange a free, no-obligation visit.