Extra bedroom and en-suite extensions in Lymm
Our extra bedroom and en-suite extensions service in Lymm covers everything: measured survey, design, planning or permitted development checks, structural design, building control and the build itself.
Quick reference for homeowners in Lymm.
- Postcode districts
- WA13
- County / area
- Cheshire, England
- Price region
- North West England
- Guide price
- £53,000–£72,000 (£1,900–£2,560 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
- Warrington (4.3 miles), Irlam (4.8 miles), Altrincham (5.3 miles)
- Distance to Warrington
- about 4.3 miles
- First visit
- Free, no obligation
About an extra bedroom and en-suite extension
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.
Around Lymm we also work in Warrington, Irlam and Altrincham, and across the rest of Cheshire. Postcode district in and near Lymm: WA13.
What it costs in Lymm
Expect an extra bedroom and en-suite extension in Lymm to land somewhere around £53,000–£72,000 (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). Our North West England guide rate is £1,900–£2,560 per m², including VAT. Professional fees for drawings and the structural engineer are listed separately on our prices page.
| Spec | Per m² | A 4 m × 3.5 m footprint on two floors (28 m² of new floor space) |
|---|---|---|
| Essential | £1,750–£2,360 per m² | £49,000–£66,000 |
| Standard | £1,900–£2,560 per m² | £53,000–£72,000 |
| Premium | £2,280–£3,080 per m² | £64,000–£86,000 |
Planning and building regulations in Lymm
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 Lymm homes
Escape window and fire safety
A new first-floor bedroom needs an escape window with a clear opening of at least 0.33 m², at least 450 mm wide and high, and the bottom no more than 1,100 mm above the floor, unless there is a protected route to the stairs. We design the windows to meet this.
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.
How we'd run your project
Start at your house
We come to your home in Lymm, 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.
Questions about extra bedroom and en-suite extensions in Lymm
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.
How much does an extra bedroom and en-suite extension cost in Lymm?
Our guide for North West England, which covers Lymm, is £1,900–£2,560 per m² including VAT. A typical project with a 4 m × 3.5 m footprint on two floors (28 m² of new floor space) comes to about £53,000–£72,000 (plus £5,500–£11,000 for the en-suite). Design and approval fees are extra, and we fix the build price in writing once the design is agreed.
Which postcodes do you cover around Lymm?
We cover Lymm (WA13) and nearby places including Warrington, Irlam and Altrincham, plus the rest of Cheshire. The first site visit is free.
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.
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.
Nearby
We also cover places near Lymm, including:
Other extensions in Lymm
All two-storey extension services in Lymm · Extra bedroom and en-suite extensions across Cheshire
Tell us about your house in Lymm and we'll call you back to arrange a free, no-obligation visit.