First-floor extensions in Reading
Our first-floor extensions service in Reading covers everything: measured survey, design, planning or permitted development checks, structural design, building control and the build itself.
Reading: the key facts for this kind of project.
- Postcode districts
- RG1, RG4, RG30 and RG31
- County / area
- Berkshire, England
- Price region
- South East England
- Guide price
- £27,500–£40,000 (£1,980–£2,860 per m²)
- 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
- Lower Earley (3 miles), Henley-on-Thames (6.1 miles), Wokingham (6.6 miles)
- First visit
- Free, no obligation
About a first-floor extension
A first-floor extension suits you if your house already has a single-storey extension and you need more space upstairs. You get a structural check of the existing walls and foundations, a design that ties the new floor into the house, the approvals your nation needs, building regulations approval and the build, managed by us and carried out by vetted teams working under S&K.
We cover postcode districts RG1, RG4, RG30 and RG31 in and around Reading, along with neighbouring Lower Earley, Henley-on-Thames and Wokingham.
What it costs in Reading
Our guide for South East England is £1,980–£2,860 per m² including VAT. On a project with 4 m × 3.5 m of new first-floor space (14 m²), that puts a first-floor extension in Reading at roughly £27,500–£40,000. We'll give you a written design-stage price first, then a fixed build price once the drawings are agreed.
| Spec | Per m² | 4 m × 3.5 m of new first-floor space (14 m²) |
|---|---|---|
| Essential | £1,820–£2,630 per m² | £25,500–£37,000 |
| Standard | £1,980–£2,860 per m² | £27,500–£40,000 |
| Premium | £2,380–£3,430 per m² | £33,500–£48,000 |
Planning and building regulations in Reading
In England, adding a first floor turns a single-storey extension into one of more than one storey. To be permitted development, the extension as a whole must go no more than 3 m beyond the rear wall of the original house and stay at least 7 m from the rear boundary, with matching materials and roof pitch. Over a side extension it always needs 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 Reading homes
Replacing the flat roof
The existing roof usually comes off and is replaced by a new first-floor structure. The room below is exposed for a short time, so we plan temporary weatherproofing and sequence the work to keep the kitchen or living room usable for as long as possible.
Escape 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 450 mm high, with the bottom no more than 1,100 mm above the floor, unless there is a protected route to the stairs.
How we'd run your project
Start at your house
We come to your home in Reading, measure up, check the ground floor walls and roof structure, and note anything near the boundaries.
Get it approved
Once you're happy with the design we submit it to the council for Reading and deal with any questions from the planning officer.
Structure and building control
A structural engineer sizes the foundations and steels, and we get building regulations approval before work starts.
Build it
The new structure goes up first, then we open into the house, finish inside and get the completion certificate.
Questions about first-floor extensions in Reading
How long does a first-floor 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.
Who handles building regulations for a project in Reading?
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.
Do I need planning permission for a first-floor extension in Reading?
Reading 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.
Will the first-floor extension match my house?
It should, and in England matching materials and roof pitch is a condition of permitted development. We match brick, tile, mortar colour and window style where we can, and tell you at the design stage if an exact brick match is not available, so you can choose between the closest match and render or cladding.
Can I build on top of my existing single-storey extension?
Often yes, but only after the structure has been checked. Foundations, walls and lintels built for one storey may not carry two. We dig trial holes, look for the original building control approval and ask the structural engineer to confirm what can stay, what needs strengthening and what must be rebuilt.
Nearby
Other towns near Reading:
Other extensions in Reading
- Rear
- Side
- Wraparound
- Part two-storey
- Over a garage
- Semi-detached
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Reading · First-floor extensions across Berkshire
Tell us about your house in Reading and we'll call you back to arrange a free, no-obligation visit.