Extra bedroom and en-suite extensions in Nelson (Mid Glamorgan)
For an extra bedroom and en-suite extension in Nelson (Mid Glamorgan), the first questions are always the same: how big, which approvals, and what it will cost. This page answers all three for Mid Glamorgan.
Nelson (Mid Glamorgan): the key facts for this kind of project.
- Postcode districts
- CF46
- County / area
- Mid Glamorgan, Wales
- Price region
- Wales
- Guide price
- £51,500–£69,500 (£1,840–£2,480 per m²), plus £5,500–£11,000 for the en-suite
- Approval route
- It may be permitted development if the ground floor goes no more than 4 m and the first floor no more than 3 m beyond the original rear wall, with the first floor 10.5 m from the rear boundary.
- Nearest towns
- Treharris (1.2 miles), Gelligaer (1.4 miles), Abercynon (1.9 miles)
- Distance to Rhondda
- about 7.1 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.
Nelson (Mid Glamorgan) sits about 7.1 miles from Rhondda. Closer to home, Treharris is 1.2 miles away and Gelligaer 1.4 miles.
What it costs in Nelson (Mid Glamorgan)
In Wales, which includes Nelson (Mid Glamorgan), we'd expect an extra bedroom and en-suite extension to cost around £51,500–£69,500 (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), or £1,840–£2,480 per m² including VAT. Design fees, structural calculations and approval fees are separate and listed on our prices page.
| Spec | Per m² | A 4 m × 3.5 m footprint on two floors (28 m² of new floor space) |
|---|---|---|
| Essential | £1,690–£2,290 per m² | £47,500–£64,000 |
| Standard | £1,840–£2,480 per m² | £51,500–£69,500 |
| Premium | £2,210–£2,980 per m² | £62,000–£83,500 |
Planning and building regulations in Nelson (Mid Glamorgan)
In Wales, an extra bedroom at the rear can be permitted development if the first floor goes no more than 3 m beyond the original rear wall and stays 10.5 m from the rear boundary. A two-storey side extension can also qualify if it is 10.5 m from the side boundary, set back 1 m and adds no more than 50% width. Otherwise the fee is £585.
Approval in Wales: Householder planning application: £585. Councils normally decide householder applications within 8 weeks.
Building regulations: Building regulations approval under the Welsh Approved Documents, which differ from England's in places (notably energy efficiency).
Design points for Nelson (Mid Glamorgan) homes
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.
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
Visit and first ideas
One of our team visits your house in Nelson (Mid Glamorgan), checks the walls, roof and drains, and sketches out options with you.
Drawings, then consent
We draw the scheme, check it against the rules in Wales, and take it through the right consent with the council.
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
Foundations, walls, floor, roof, windows, then first and second fix. We break through into the house as late as we can.
Questions about extra bedroom and en-suite extensions in Nelson (Mid Glamorgan)
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 normally decide householder applications within 8 weeks), 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.
Which postcodes do you cover around Nelson (Mid Glamorgan)?
We cover Nelson (Mid Glamorgan) (CF46) and nearby places including Treharris, Gelligaer and Abercynon, plus the rest of Mid Glamorgan. The first site visit is free.
Who handles building regulations for a project in Nelson (Mid Glamorgan)?
We handle it as part of the project. What's needed in Wales: building regulations approval under the Welsh Approved Documents, which differ from England's in places (notably energy efficiency). We prepare the drawings and the engineer's calculations, book the inspections and pass you the completion paperwork at the end.
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.
Nearby
The same service in neighbouring towns:
Other extensions in Nelson (Mid Glamorgan)
All two-storey extension services in Nelson (Mid Glamorgan) · Extra bedroom and en-suite extensions across Mid Glamorgan
Book a free site visit in Nelson (Mid Glamorgan) and we'll tell you what's possible, what approvals you need and what the design stage would cost.