Extra bedroom and en-suite extensions in Royston (Cambridgeshire)
Want to stay in Royston (Cambridgeshire) but need more space? An extra bedroom and en-suite extension adds floor area on two levels without giving up much garden. Here's what's involved.
Quick reference for homeowners in Royston (Cambridgeshire).
- Postcode districts
- SG8
- County / area
- Cambridgeshire, England
- Price region
- East of England
- Guide price
- £57,500–£78,000 (£2,060–£2,780 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
- Baldock (8.1 miles), Letchworth Garden City (9.8 miles), Biggleswade (10.6 miles)
- Distance to Peterborough
- about 37.5 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%.
Around Royston (Cambridgeshire) we also work in Baldock, Letchworth Garden City and Biggleswade, and across the rest of Cambridgeshire. Postcode district in and near Royston (Cambridgeshire): SG8.
What it costs in Royston (Cambridgeshire)
A guide price for Royston (Cambridgeshire): around £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). That works out at £2,060–£2,780 per m² of new floor space, including VAT at 20%. 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 | £1,900–£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 |
Planning and building regulations in Royston (Cambridgeshire)
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 Royston (Cambridgeshire) homes
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.
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.
How we'd run your project
Visit and first ideas
One of our team visits your house in Royston (Cambridgeshire), 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 England, 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 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 Royston (Cambridgeshire)
Do I need planning permission for an extra bedroom and en-suite extension in Royston (Cambridgeshire)?
Royston (Cambridgeshire) 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.
Who handles building regulations for a project in Royston (Cambridgeshire)?
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.
Which postcodes do you cover around Royston (Cambridgeshire)?
We cover Royston (Cambridgeshire) (SG8) and nearby places including Baldock, Letchworth Garden City and Biggleswade, plus the rest of Cambridgeshire. The first site visit is free.
How big should a new double bedroom be?
There is no legal minimum size for a bedroom in a house you own, so the test is whether it works. A comfortable double needs room for the bed with space to walk round it, wardrobes and a door that opens freely. We draw furniture on the plans so you can judge the space before anything is built.
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
Other towns near Royston (Cambridgeshire):
Other extensions in Royston (Cambridgeshire)
All two-storey extension services in Royston (Cambridgeshire) · Extra bedroom and en-suite extensions across Cambridgeshire
Book a free site visit in Royston (Cambridgeshire) and we'll tell you what's possible, what approvals you need and what the design stage would cost.