House Extension
Builders in Oxford.
Trusted house extension specialists across Oxford and Oxfordshire. We manage the whole project under one roof — design, planning permission, structural calculations and the build itself.
Extensions
Fully licensed, insured, and custom-engineered services in Oxfordshire.
Trusted house extension specialists
across Oxford and Oxfordshire.
Crawford Construction designs and builds house extensions in Oxford for homeowners who want more space without the upheaval of moving. From a single-storey kitchen extension on a Victorian terrace in Headington to a double-storey addition on a 1930s semi in Summertown, we manage the whole project under one roof — design, planning permission, structural calculations and the build itself — with a fixed-price quote and a named project manager from first site visit to final handover.
As FMB-listed Oxford builders with work completed across the county since 2003, we understand the difference between extending a period property bound by conservation rules and extending a modern home where the challenge is matching today's energy standards. Both demand a builder who knows Oxford — its housing stock, its planning authorities and its character.
Extending older and period properties in Oxford
A large share of Oxford's housing is old — Victorian and Edwardian terraces, North Oxford villas, 1930s semis and Cotswold stone cottages out toward Witney and the Cotswolds. Extending these homes well means respecting what's already there.
Many sit within an Oxford conservation area or carry an Article 4 Direction, which removes some permitted development rights and means a rear or side extension that would be automatic elsewhere needs full planning permission here. Where a property is a listed building, any alteration also requires Listed Building Consent, with Historic England guidance shaping what's allowed.
We handle this sensitively: lime mortar and reclaimed or Cotswold stone to match existing elevations, careful detailing around original features, and structural work — RSJ steel beams, lintels and underpinning — engineered by a chartered structural engineer so the new opening or storey is sound. The result reads as though it was always part of the house.
Typical period-property work includes:
Extensions for modern and new-build homes
Newer homes in areas like Bicester, Didcot and Kidlington bring a different brief. Here the work is usually about lifestyle and value — a larger kitchen-diner, a ground-floor annexe, or a two-storey extension adding bedrooms and a bathroom above living space below.
The technical focus shifts to performance: meeting current Building Regulations (including Part L for energy efficiency), high levels of insulation, underfloor heating, and glazing that floods the space with light — bi-fold or sliding doors, roof lanterns and rooflights. Because the existing build is consistent and well-documented, modern extensions often move faster through design and Building Control sign-off.
Local Project Examples
Double-Storey Side Extension & Garage Conversion - Abingdon
View Projects GalleryOxford Project Seal
Fully Insured & Guaranteed
10-Year structural warranty covered.
Types of house extension we build
Choosing the right structural configuration matches your property's boundary layout with your living goals.
| Extension Type | Best For | Typical Use |
|---|---|---|
| Single-storey rear | Most Oxford homes | Kitchen-diner, family room |
| Single-storey side return | Victorian/Edwardian terraces | Widening a narrow kitchen |
| Wrap-around | Terraces & semis with side access | Full open-plan ground floor |
| Double / two-storey | Semis & detached homes | Extra bedrooms + downstairs space |
| Over-structure (above garage/kitchen) | Homes with an existing single-storey element | Adding a room without losing garden |
| Kitchen extension | All property types | Open-plan cooking and dining |
Planning permission and building regulations in Oxford
Where you live in the county determines who decides your application. We deal regularly with Oxford City Council, Cherwell District Council, South Oxfordshire District Council, Vale of White Horse District Council and West Oxfordshire District Council, and we prepare and submit through the Planning Portal on your behalf.
We advise from day one on whether your project falls under permitted development or needs a full householder planning application, and we factor in the Party Wall etc. Act 1996 where your extension affects a shared boundary with a neighbour. Building Regulations approval and Building Control inspections are handled in-house as part of our design-and-build service, so nothing falls between an architect and a builder — there's only ever one team accountable.
How much does a house extension cost in Oxford?
Most single-storey extensions in Oxford currently fall around £2,800–£3,500 per square metre, depending on specification, access, ground conditions and finish. Double-storey work, listed-property detailing and high-end glazing change the figures again.
Because every house — and every Oxford street — is different, we don't quote from a calculator. We provide a free, itemised, fixed-price quote after a site visit, so you can budget with real numbers and know exactly where your investment goes. No vague estimates, and no surprises halfway through.
Why choose Crawford Construction
as your Oxford extension builder.
FMB-listed quality
Certified and vetted to strict Federation of Master Builders quality standards.
Fixed-price guarantee
Completely itemised quotes, with payment stages structured as work is completed.
One named project manager
James Crawford, Project Director, handles your build from first visit to final snagging.
10-year warranty
Full comprehensive insurance-backed structural guarantees for absolute safety.
Local knowledge
Deep understanding of Oxford's planning authorities, conservation areas and housing stock that saves time.
Areas we serve
We build house extensions across Oxford City Centre, Headington, Summertown, Jericho, Cowley, Iffley, North Oxford and Botley, and throughout Oxfordshire including Witney, Bicester, Abingdon, Didcot, Kidlington, Woodstock, Thame, Banbury and the Cotswolds.
Start your Oxford house extension
Tell us about your project and we'll reply within 24 hours with the next steps. Free, no-obligation, and 100% confidential.
Frequently asked questions
Everything you need to know about extensions, planning and calculations in Oxfordshire.
Not always. Many single-storey rear extensions fall under permitted development. But if your home is in an Oxford conservation area, carries an Article 4 Direction, or is a listed building, you'll likely need full planning permission or Listed Building Consent. We assess this for you before any design work begins.
A typical single-storey extension runs around 10–16 weeks on site once approvals are in place; double-storey and listed-property projects take longer. Design and planning add time at the front end, which is why we start that process early.
Yes — period extensions are a core part of our work. We match materials such as Cotswold stone and brick, detail sensitively around original features, and navigate conservation and listed-building rules with the relevant council and Historic England.
Yes. As a design-and-build firm we manage feasibility, surveys, the planning application through the Planning Portal, structural calculations and Building Control inspections in-house, so you have a single point of contact throughout.
Always. After a site visit we provide a free, itemised, fixed-price quote, and you pay as work is completed rather than a large deposit upfront.
Let's build
somethingremarkable.
From first sketch to final handover — Oxfordshire's trusted team for homes built with precision, craftsmanship and care.
