Extensions that enhance, not just enlarge
A well-designed extension is never an afterthought. At Gresford Architects, extensions are an opportunity to reimagine how homes across Oxford, the Cotswolds, the Chilterns, London and the wider South East are lived in, experienced and loved. From the terraced houses of Jericho to Cotswold stone cottages and suburban semis in North London, each project is rooted in its context and designed for lasting value.
Extension design is the art of expanding and upgrading a home in ways that elevate both form and function. For us, it is more than 'adding on' — it is about creating interventions that feel as if they were always meant to be there.
We specialise in:
Every extension begins with listening. We study how you live — frustrations, routines, aspirations — and uncover the untapped potential of your existing home.
Extensions must feel seamless. We analyse daylight, solar gain, views, materials and movement. Using daylight analysis and solar modelling, we ensure that new spaces are light, balanced and energy-efficient.
An extension is also an opportunity to improve the whole home. We integrate airtightness continuity, thermal bridge modelling (Ψ-values), and triple glazing, alongside natural, vapour-open materials to protect older walls.
Where new meets old, we design carefully for moisture control (using WUFI hygrothermal modelling) and structural load. Steelwork, foundations and junction detailing are resolved with both safety and elegance in mind.
We guide you through the complexities of permitted development rights, full planning permission and Listed Building Consent. Our experience with authorities such as Oxford City Council and Cotswold District Council ensures applications are evidence-based and persuasive.
Extensions are personal journeys. We work with you, specialist craftspeople, and consultants in a transparent, iterative process. Visualisations and models help translate complexity into clarity at every stage.
Ickburgh Road — a light-filled kitchen/dining extension transformed a dark ground floor into the social heart of the home with an exposed timber structure and textured brick exterior.
Graham Street — a dark blue rendered pavilion added light and openness while respecting the building’s vernacular charm.
Lavender Grove — a ground floor rear extension reconfigured circulation, upgraded thermal performance, and maximised garden views with a zinc clad extension.
Albyn Road — a ground floor rear extension with an angular roof that abstracts the local vernacular, allowing a play of light that constantly changes deep into the plan.
As a RIBA Chartered Practice, ARB-registered architects, members of the Passivhaus Trust and the Society for the Protection of Ancient Buildings (SPAB), we bring award-winning experience to the challenge of extending homes with care. Our projects — from The Deerings (RIBA East Award, 2018; RIBA House of the Year longlist) to The Great Barn — demonstrate how thoughtful interventions can both respect heritage and transform modern living.
Some smaller projects fall under permitted development rights, but many require planning permission — especially in conservation areas or for listed buildings.
Budgets typically range from £100,000 to £500,000+, depending on scope, complexity and finishes. We provide detailed cost plans during feasibility
From kitchen/dining spaces to two-storey additions and heritage-sensitive pavilions, we design across all scales.
Yes, with Listed Building Consent. Our work on The Great Barn shows how heritage character can be preserved while improving liveability.
Most projects run 9–18 months from design to completion, depending on permissions and build scale.
Yes. Extensions typically enhance both liveability and resale value, particularly when designed with energy efficiency and long-term adaptability in mind.
Through material integrity, contextual analysis and precision detailing. We believe in the marriage of the poetic and the practical — restoring the character of the old while introducing contemporary interventions that feel timeless.
Contemporary designs often use glass, steel and timber to create contrast and light, while traditional extensions blend more closely with existing materials. We advise on both approaches depending on context and client aspirations.
