Two-storey annexe extensions in Cheshire

Cheshire at a glance

Nation: England
Price region: North West England
Postcode areas: CH, CW, SK, WA
Towns covered: 20 listed below, plus surrounding villages
Approval route: Planning permission is needed: in England, permitted development only allows single-storey extensions to the side.
Site visits: Free, no obligation

What a two-storey annexe extension involves

A two-storey annexe extension is an attached extension laid out as self-contained living space on two floors, usually with a living area and kitchenette below and a bedroom and shower room above, for a relative living with the family. It stays part of the main house rather than a separate home. Planning and council tax rules treat it differently from a separate dwelling.

The main places we list in Cheshire are Warrington (WA1), Chester (CH2), Crewe (CW1), Ellesmere Port (CH65), Widnes (WA8) and Runcorn (WA6). We cover the villages in between too.

Guide price in North West England

Most of the cost of a two-storey annexe extension is set by its size and specification. For Cheshire and the rest of North West England, our guide is £1,950–£2,610 per m² including VAT, so about £82,000–£109,500 (plus kitchenette and shower room fittings, priced to your choice) for a 3 m × 7 m footprint on two floors (42 m² of new floor space). Kitchens, bathroom fittings and flooring are priced separately so you can compare like with like.

Spec	Per m²	Typical project
Essential	£1,790–£2,400 per m²	£75,500–£101,000
Standard	£1,950–£2,610 per m²	£82,000–£109,500
Premium	£2,340–£3,130 per m²	£98,000–£131,500

Rules in England

In England, an annexe on two floors is assessed like any two-storey extension: at the rear it can be permitted development if it goes no more than 3 m beyond the original rear wall and stays 7 m from the rear boundary, but at the side it needs planning permission, costing £548 (or £575 for applications made from 8 December 2026). Councils often add a condition that the annexe stays ancillary to the main house and is not let separately.

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.

The Party Wall etc. Act 1996 applies, so notices may be needed for work on or near a shared wall or boundary.

Getting the design right

Services and metering

An annexe usually shares the main house's water, gas and electricity, with a separate circuit or sub-meter if you want to split costs. We plan heating, hot water and drainage so the annexe works well without needing new supplies.

Ground-floor living for the future

Many annexes are planned so the occupant could live on the ground floor if stairs become difficult. A ground-floor bedroom space, a level-access shower and wider doorways cost little at the design stage and are expensive to add later.

How we work in Cheshire

Measure and listen
A visit to Cheshire to understand how you live in the house now and what the extra rooms need to do, plus a first look at the structure.
Choose the approval route
Some designs fit permitted development, most need a householder application. We decide which applies in England before drawing in detail.
Price it properly
Once the engineer's calculations are in, we fix the build price in writing, with a clear list of what's included.
Build it
The new structure goes up first, then we open into the house, finish inside and get the completion certificate.

Towns we cover in Cheshire

Two-storey annexe extensions in Cheshire: questions

How much does a two-storey annexe extension cost in Cheshire?

In North West England our guide is £1,950–£2,610 per m² including VAT, so about £82,000–£109,500 (plus kitchenette and shower room fittings, priced to your choice) for a 3 m × 7 m footprint on two floors (42 m² of new floor space). Essential and Premium specs move that by roughly 8% down or 20% up.

Does a two-storey annexe need planning permission?

It depends on where it goes and your nation. In England, a rear annexe extension can be permitted development within the 3 m and 7 m limits, but a side one always needs planning permission. If the annexe could work as a separate home, the council may treat it as a new dwelling, which needs full planning permission.

Can an annexe have its own front door?

It can, but a separate front door, kitchen and address together make it look more like a separate home, which can change how the council treats it for planning. Many annexes have their own door to the garden or side and an internal door to the main house. We explain how each choice is likely to be viewed before the design is fixed.

Can an annexe be designed for someone with limited mobility?

Yes. We can plan a ground-floor bedroom space, a level-access shower, wider doorways, lever handles and space for a stairlift later. These features are much cheaper to build in at the start than to add afterwards, and they keep the annexe useful as needs change.

Will I need planning permission in Cheshire?

Cheshire is in England. Planning permission is needed: in England, permitted development only allows single-storey extensions to the side.

Neighbouring areas

All extension services in Cheshire · About two-storey annexe extensions