Two-storey wraparound extensions in Amersham

Quick reference for homeowners in Amersham.

Postcode districts: HP7 and HP16
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: Amersham on the Hill (0.7 miles), Chesham (2.4 miles), Beaconsfield (4 miles)
Distance to Milton Keynes: about 26.6 miles
First visit: Free, no obligation

About a two-storey wraparound extension

A two-storey wraparound extension suits a house with space both beside it and behind it, where you want to transform the layout rather than add a single room. You get one design for the whole L-shape, the planning application, structural design for the corner and the openings into the house, building regulations approval and the build, managed by us and carried out by vetted teams working under S&K.

Amersham sits about 26.6 miles from Milton Keynes. Closer to home, Amersham on the Hill is 0.7 miles away and Chesham 2.4 miles.

What it costs in Amersham

In South East England, which includes Amersham, we'd expect a two-storey wraparound extension to cost around £132,500–£181,500 for an L-shaped footprint of about 28 m² wrapping the side and rear, on two floors (56 m² of new floor space), or £2,360–£3,250 per m² including VAT. Steelwork for wide openings is the item most likely to move the figure; we'll know once the engineer has designed it.

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 Amersham

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 Amersham homes

Daylight to the middle

A deep L-shaped plan can leave the middle of the ground floor dark, because the old rear rooms are now enclosed. We use wide rear openings, a well-placed stair and, where part of the extension is single storey, roof lights, while keeping total glazing within the Part L allowance.

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

Visit and first ideas
One of our team visits your house in Amersham, checks the walls, roof and drains, and sketches out options with you.
Choose the approval route
Some designs fit permitted development, most need a householder application. We decide which applies in England before drawing in detail.
Technical design
We prepare the building regulations drawings, structural calculations and specification so the build price can be fixed.
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 Amersham

Who handles building regulations for a project in Amersham?

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 long does a two-storey wraparound extension take?

Allow 4 to 8 weeks for survey and design, then the approval period (councils should decide householder applications within 8 weeks of validation), then 4 to 8 weeks of technical design, which can overlap. The build itself usually takes 14 to 20 weeks, longer for large or complex designs.

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

Amersham 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.

Can I stay at home during a wraparound extension?

Many people do, but a wraparound affects two sides of the house and usually the kitchen, so there will be weeks without a full kitchen. We plan a temporary kitchen, keep a route through the house and seal off the work area. For some families, moving out while the rear wall is opened up is easier.

Can a wraparound extension be part single, part two-storey?

Yes. Many wraparounds keep the rear part single storey with roof lights over the kitchen and put the two-storey part to the side. This can reduce the effect on neighbours and the cost. We set out both options at the design stage, so you can compare floor space against price before choosing.

Nearby

We also cover places near Amersham, including:

Other extensions in Amersham

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

Want a figure first? Try our guide price tool, then book a free visit to firm it up.