Two-storey wraparound extensions in Marlow

Before you start in Marlow, here's what applies.

Postcode districts: SL7 and SL8
County / area: Buckinghamshire, England
Price region: South East England
Guide price: £132,500–£181,500 (£2,360–£3,250 per m²)
Approval route: Planning permission is needed: the side part takes it outside permitted development in England.
Nearest towns: Maidenhead (4 miles), High Wycombe (4.3 miles), Burnham (5.2 miles)
Distance to Milton Keynes: about 32.6 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.

We cover postcode districts SL7 and SL8 in and around Marlow, along with neighbouring Maidenhead, High Wycombe and Burnham.

What it costs in Marlow

Using our South East England rates, a two-storey wraparound extension with an L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space) comes to about £132,500–£181,500, including VAT. Bigger or more glazed designs cost more per m². The fastest way to a firmer number is a free site visit, after which we price the design stage in writing.

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	£2,180–£2,990 per m²	£122,000–£167,000
Standard	£2,360–£3,250 per m²	£132,500–£181,500
Premium	£2,840–£3,890 per m²	£159,000–£218,000

Planning and building regulations in Marlow

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 Marlow 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

Measure and listen
A visit to Marlow to understand how you live in the house now and what the extra rooms need to do, plus a first look at the structure.
Get it approved
Once you're happy with the design we submit it to the council for Marlow and deal with any questions from the planning officer.
Engineer it
Foundations sized for two floors, steels for any openings, and building control approval, all before anyone starts on site.
Build it
The new structure goes up first, then we open into the house, finish inside and get the completion certificate.

Questions about two-storey wraparound extensions in Marlow

Which postcodes do you cover around Marlow?

We cover Marlow (SL7 and SL8) and nearby places including Maidenhead, High Wycombe and Burnham, plus the rest of Buckinghamshire. The first site visit is free.

Who handles building regulations for a project in Marlow?

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.

How much does a two-storey wraparound extension cost in Marlow?

Our guide for South East England, which covers Marlow, is £2,360–£3,250 per m² including VAT. A typical project with an L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space) comes to about £132,500–£181,500. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

How much floor space does a wraparound extension add?

It depends on the width of the side plot and the depth at the rear. Our guide prices are based on a typical wraparound with an L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space). Yours may be larger or smaller, and the measured survey shows what your plot can take.

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.

Nearby

Close to Marlow? We work across the area, including:

Other extensions in Marlow

All two-storey extension services in Marlow · Two-storey wraparound extensions across Buckinghamshire

Book a free site visit in Marlow and we'll tell you what's possible, what approvals you need and what the design stage would cost.