Extra bedroom and en-suite extensions in Bristol

Bristol at a glance

Nation: England
Price region: South West England
Postcode areas: BS
Towns covered: 7 listed below, plus surrounding villages
Approval route: It may be permitted development if it goes no more than 3 m beyond the original rear wall (counting any single-storey part) and stays 7 m from the rear boundary; otherwise it needs planning permission.
Site visits: Free, no obligation

What an extra bedroom and en-suite extension involves

This service suits you if you need another bedroom, or want a main bedroom with its own bathroom, without converting the loft or moving. You get a first-floor layout that connects well to your landing, an en-suite designed for plumbing and ventilation, a useful room downstairs, the approvals your nation needs and the build, managed by us and carried out by vetted teams working under S&K.

Across Bristol we cover Bishopsworth (BS13), Easton-in-Gordano (BS11), Severn Beach (BS10), Chew Magna (BS13), Dundry (BS13) and Whitchurch (Bristol) (BS14), plus the smaller places around them.

Guide price in South West England

Using our South West England rates, an extra bedroom and en-suite extension with a 4 m × 3.5 m footprint on two floors (28 m² of new floor space) comes to about £57,500–£78,000 (plus £5,500–£11,000 for the en-suite), including VAT. Bigger or more glazed designs cost more per m². Keep a contingency of around 10% for things nobody can see until the ground is opened up.

Spec	Per m²	Typical project
Essential	£1,900–£2,560 per m²	£53,000–£71,500
Standard	£2,060–£2,780 per m²	£57,500–£78,000
Premium	£2,470–£3,340 per m²	£69,000–£93,500

Rules in England

In England, an extra bedroom extension at the rear 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. Upper side windows, including en-suite windows, must be obscure-glazed and non-opening below 1.7 m. Side or deeper designs need planning permission, costing £548 (or £575 for applications made from 8 December 2026).

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

Planning the en-suite

An en-suite needs a route for the soil pipe to the drains, enough fall for waste water and an extract fan to the outside under Part F. Placing it over the ground-floor utility or near an existing drain keeps pipework short and hidden.

Sound and privacy

Bedrooms above a kitchen or family room benefit from an insulated floor to reduce noise. Side-facing upstairs windows usually have to be obscure-glazed, so we place the main bedroom window to the rear and the en-suite window to the side where possible.

How we work in Bristol

Start at your house
We come to your home in Bristol, measure up, check the ground floor walls and roof structure, and note anything near the boundaries.
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.
Fixed price in writing
With approved drawings and calculations, we give you a fixed build price and a programme you can plan around.
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 Bristol

Extra bedroom and en-suite extensions in Bristol: questions

How much does an extra bedroom and en-suite extension cost in Bristol?

In South West England our guide is £2,060–£2,780 per m² including VAT, so about £57,500–£78,000 (plus £5,500–£11,000 for the en-suite) for a 4 m × 3.5 m footprint on two floors (28 m² of new floor space). Essential and Premium specs move that by roughly 8% down or 20% up.

Can an en-suite go in a room with no window?

Yes. A shower room without a window is allowed, provided it has a mechanical extract fan to the outside that meets Part F. Many people prefer a window for daylight, but if it faces a neighbour it will usually need obscure glass. We plan the extract route early so the duct is hidden.

Does an extra bedroom add value to my house?

It usually does, though not always by the full cost. Nationwide's 2025 research found that adding a double bedroom to a two-bed house was linked to about 13% higher value, and a double bedroom and bathroom on a three-bed, one-bathroom house up to 24%. Local ceiling prices still apply.

What goes on the ground floor below a new bedroom?

Whatever suits you: a bigger kitchen, a family room, a study, a utility or a downstairs shower room. The ground floor usually costs about the same whatever it is used for, apart from kitchen units and bathroom fittings, which are priced separately.

Will I need planning permission in Bristol?

Bristol is in England. It may be permitted development if it goes no more than 3 m beyond the original rear wall (counting any single-storey part) and stays 7 m from the rear boundary; otherwise it needs planning permission.

Neighbouring areas

All extension services in Bristol · About extra bedroom and en-suite extensions