Two-storey extensions for detached houses in Royston (Cambridgeshire)
Homes in Royston (Cambridgeshire) with a bit of space to the side or rear can often take a two-storey extension for a detached house. We'll tell you honestly whether yours can, and what approvals it needs.
What we'd confirm first for a project in Royston (Cambridgeshire).
- Postcode districts
- SG8
- County / area
- Cambridgeshire, England
- Price region
- East of England
- Guide price
- £88,500–£119,000 (£2,110–£2,830 per m²)
- Approval route
- Depends on position: a two-storey rear extension may be permitted development (3 m deep, 7 m from the rear boundary); a two-storey side extension 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 a two-storey extension for a detached house
This service suits you if you own a detached house and want a substantial amount of extra space, whether a side extension over a drive, a rear extension into the garden or a wraparound. You get a survey of the whole plot, options that compare layouts and costs, the approvals your nation needs, structural design and the build, carried out by vetted teams working under S&K.
Royston (Cambridgeshire) sits about 37.5 miles from Peterborough. Closer to home, Baldock is 8.1 miles away and Letchworth Garden City 9.8 miles.
What it costs in Royston (Cambridgeshire)
Expect a two-storey extension for a detached house in Royston (Cambridgeshire) to land somewhere around £88,500–£119,000 for a 3 m × 7 m footprint on two floors (42 m² of new floor space). Our East of England guide rate is £2,110–£2,830 per m², including VAT. Steelwork for wide openings is the item most likely to move the figure; we'll know once the engineer has designed it.
| Spec | Per m² | A 3 m × 7 m footprint on two floors (42 m² of new floor space) |
|---|---|---|
| Essential | £1,940–£2,610 per m² | £81,500–£109,500 |
| Standard | £2,110–£2,830 per m² | £88,500–£119,000 |
| Premium | £2,530–£3,400 per m² | £106,500–£143,000 |
Planning and building regulations in Royston (Cambridgeshire)
In England, a two-storey rear extension on a detached house can be permitted development within 3 m of the original rear wall and at least 7 m from the rear boundary, with matching roof pitch and materials, outside protected areas. Any two-storey side or wraparound extension needs planning permission, costing £548 (or £575 for applications made from 8 December 2026), with a decision due within 8 weeks of validation.
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
Choosing the best side
On a detached house you can often extend on either side or the rear. We look at orientation for daylight, where the stairs and landing are, the distance to each boundary, drains and trees, so the extension goes where it adds the most useful space.
Larger spans and steelwork
Bigger extensions often mean wider openings and longer spans, which need more steel and sometimes a steel frame. The engineer designs these early, because the size of the steel affects ceiling heights, floor depths and the cost.
How we'd run your project
Free site visit
We visit your home in Royston (Cambridgeshire), look at the structure, access and boundaries, and talk through what you want the new rooms to do.
Get it approved
Once you're happy with the design we submit it to the council for Royston (Cambridgeshire) and deal with any questions from the planning officer.
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.
Finish and certify
Second fix, plastering and making good, then building control's final inspection and the completion paperwork.
Questions about two-storey extensions for detached houses in Royston (Cambridgeshire)
How much does a two-storey extension for a detached house cost in Royston (Cambridgeshire)?
Our guide for the East of England, which covers Royston (Cambridgeshire), is £2,110–£2,830 per m² including VAT. A typical project with a 3 m × 7 m footprint on two floors (42 m² of new floor space) comes to about £88,500–£119,000. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.
How long does a two-storey extension for a detached house 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 a two-storey extension for a detached house in Royston (Cambridgeshire)?
Royston (Cambridgeshire) is in England, so England planning rules apply. Depends on position: a two-storey rear extension may be permitted development (3 m deep, 7 m from the rear boundary); a two-storey side extension needs planning permission. If in doubt, a lawful development certificate or a planning application gives you certainty before you build.
Can I extend a detached house on both sides?
Sometimes. With planning permission, a council may accept extensions on both sides if the house stays well proportioned and keeps gaps to the boundaries. It is more common to extend on one side and the rear, or with a wraparound. We look at the plot as a whole before suggesting more than one extension.
How big an extension can a detached house take?
It depends on the plot, the boundaries and local design policy rather than a fixed limit. Under permitted development in England, extensions must not cover more than 50% of the land around the original house. With planning permission, the council judges size on proportion, neighbours and the character of the area.
Nearby
Nearby towns we cover for two-storey extensions for detached houses:
Other extensions in Royston (Cambridgeshire)
- Rear
- Side
- Wraparound
- Part two-storey
- Over a garage
- First floor
- Semi-detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Royston (Cambridgeshire) · Two-storey extensions for detached houses across Cambridgeshire
Ready to talk it through? Call us or send the form and we'll arrange a visit to your home in Royston (Cambridgeshire).