Extra bedroom and en-suite extensions in Guildford
Adding an extra bedroom and en-suite extension in Guildford gives you two new rooms stacked on one footprint. Here's how we'd approach it, what it typically costs and the rules that apply in England.
Guildford: the key facts for this kind of project.
- Postcode districts
- GU1, GU2, GU3, GU4 and GU5
- County / area
- Surrey, England
- Price region
- South East England
- Guide price
- £61,500–£83,000 (£2,200–£2,970 per m²), plus £5,500–£11,000 for the en-suite
- 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.
- Nearest towns
- Godalming (3.8 miles), Woking (5.8 miles), Cranleigh (7.5 miles)
- Distance to Woking
- about 5.8 miles
- First visit
- Free, no obligation
About an extra bedroom and en-suite extension
An extra bedroom and en-suite extension is a two-storey extension planned around a new double bedroom with its own shower room on the first floor, with a ground-floor room below. It is one of the most effective ways to add space for a growing family. Nationwide's 2025 research linked adding a double bedroom and bathroom to a three-bed, one-bathroom house with value gains of up to 24%.
We cover postcode districts GU1, GU2, GU3, GU4 and GU5 in and around Guildford, along with neighbouring Godalming, Woking and Cranleigh.
What it costs in Guildford
Using our South East 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 £61,500–£83,000 (plus £5,500–£11,000 for the en-suite), including VAT. Bigger or more glazed designs cost more per m². We'll give you a written design-stage price first, then a fixed build price once the drawings are agreed.
| Spec | Per m² | A 4 m × 3.5 m footprint on two floors (28 m² of new floor space) |
|---|---|---|
| Essential | £2,020–£2,730 per m² | £56,500–£76,500 |
| Standard | £2,200–£2,970 per m² | £61,500–£83,000 |
| Premium | £2,640–£3,560 per m² | £74,000–£100,000 |
Planning and building regulations in Guildford
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.
Design points for Guildford homes
Connecting to the landing
The new bedroom must be reached from the existing landing, usually through a new opening in the outside wall or by taking part of an existing bedroom as a corridor. We look at the stairs and landing first, because a poor connection can waste much of the new space.
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.
How we'd run your project
Measure and listen
A visit to Guildford 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 Guildford and deal with any questions from the planning officer.
Fixed price in writing
With approved drawings and calculations, we give you a fixed build price and a programme you can plan around.
Build and sign-off
Vetted teams working under S&K build the extension, and we arrange the building control completion certificate at the end.
Questions about extra bedroom and en-suite extensions in Guildford
Who handles building regulations for a project in Guildford?
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 an extra bedroom and en-suite 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 an extra bedroom and en-suite extension in Guildford?
Guildford is in England, so England planning rules apply. 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. If in doubt, a lawful development certificate or a planning application gives you certainty before you build.
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.
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.
Nearby
Nearby towns we cover for extra bedroom and en-suite extensions:
Other extensions in Guildford
All two-storey extension services in Guildford · Extra bedroom and en-suite extensions across Surrey
Send us your postcode and a few details. We'll get back to you to arrange a visit and talk through your options.