Two-storey extensions for detached houses in Redhill

Redhill: the key facts for this kind of project.

Postcode districts: RH1
County / area: Surrey, England
Price region: South East England
Guide price: £94,500–£127,000 (£2,260–£3,030 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: Reigate (1.5 miles), Horley (4.6 miles), Caterham (4.9 miles)
Distance to Woking: about 17.6 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.

Around Redhill we also work in Reigate, Horley and Caterham, and across the rest of Surrey. Postcode district in and near Redhill: RH1.

What it costs in Redhill

Expect a two-storey extension for a detached house in Redhill to land somewhere around £94,500–£127,000 for a 3 m × 7 m footprint on two floors (42 m² of new floor space). Our South East England guide rate is £2,260–£3,030 per m², including VAT. We'll give you a written design-stage price first, then a fixed build price once the drawings are agreed.

Spec	Per m²	A 3 m × 7 m footprint on two floors (42 m² of new floor space)
Essential	£2,070–£2,780 per m²	£87,000–£117,000
Standard	£2,260–£3,030 per m²	£94,500–£127,000
Premium	£2,710–£3,630 per m²	£113,500–£152,500

Planning and building regulations in Redhill

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 Redhill 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

Start at your house
We come to your home in Redhill, measure up, check the ground floor walls and roof structure, and note anything near the boundaries.
Choose the approval route
Some designs fit permitted development, most need a householder application. We decide which applies in England before drawing in detail.
Structure and building control
A structural engineer sizes the foundations and steels, and we get building regulations approval before work starts.
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 two-storey extensions for detached houses in Redhill

Which postcodes do you cover around Redhill?

We cover Redhill (RH1) and nearby places including Reigate, Horley and Caterham, plus the rest of Surrey. The first site visit is free.

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.

Who handles building regulations for a project in Redhill?

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 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.

Is a detached house extension a better investment than moving?

It often costs less than the gap between your house and a larger one nearby, once property tax, legal fees and removal costs are counted, but that depends on your area. Extending also has limits: every street has a ceiling price. We give you build costs so you can compare them with local asking prices.

Nearby

Close to Redhill? We work across the area, including:

Other extensions in Redhill

All two-storey extension services in Redhill · Two-storey extensions for detached houses 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.