The Brief
Our Basingstoke clients had a young and growing family — three children, regular visits from grandparents, and a house that had simply stopped working for the way they lived. The original layout had a narrow kitchen at the rear and a separate, underused dining room. They wanted the two merged into one generous, light-filled space that would work for school-morning routines, weekend cooking and entertaining alike.
Our Design Approach
We designed a 34m² flat-roof extension across the full width of the rear of the property, removing the original rear wall entirely to create a seamless transition between the existing house and new space. A central structural steel beam carries the load above the opening, disguised within a plastered ceiling soffit. The flat roof is punctuated by a double-height roof lantern positioned above the dining area — a source of overhead light that transforms the feel of the space throughout the day.
Bi-fold doors span the full width of the rear wall, opening the new kitchen-diner entirely to the garden in fine weather. In winter, the thermally broken aluminium frames and triple-glazed units ensure the space is warm and efficient. Underfloor heating replaces the need for radiators, keeping wall space free and floors comfortable year-round.
Planning and Approvals
The extension fell within the parameters of Permitted Development — it did not require a full planning application. We prepared and submitted a Lawful Development Certificate application to provide the clients with formal confirmation that the works were lawful. Building Regulations approval covered structural design, thermal performance, drainage and the floor-to-ceiling glazing specification.
Key Design Features
- Full-width bi-fold doors: Seven-panel aluminium bi-fold system opening the extension to the garden
- Roof lantern: Double-height glazed lantern above the dining area for overhead natural light
- Structural steel opening: RSJ beam enabling full rear wall removal without visible post
- Underfloor heating: Warm water UFH throughout the new slab — no radiators needed
- Open-plan layout: Kitchen, dining and informal seating all in one connected space
The Result
The finished extension has completely changed how this family uses their home. Mornings are calmer, meals are more sociable, and in summer the bi-fold doors stay open from breakfast to bedtime. The overhead light from the roof lantern means the space never feels cave-like — even on grey Hampshire days, the room is flooded with diffused natural light. It is a project that illustrates the core proposition of a well-designed rear extension: not just more space, but a fundamentally better home.
Cost and Package Guidance
For a 34m² contemporary extension in Basingstoke, the biggest budget variables are usually structural steelwork, glazing specification, drainage changes, foundation conditions and final kitchen, bathroom or joinery choices. Hampshire Build's fixed-fee design packages give homeowners clear design-cost certainty before construction begins, with Essential, Pre-Build and Premium options depending on how much technical documentation and contractor support is needed. The design fee is separate from builder costs, planning fees, Building Control fees and any third-party specialist reports, so clients can make informed decisions without confusing design work with the wider construction budget.
Local Context and Practical Considerations
Projects in Basingstoke benefit from early attention to neighbouring amenity, overlooking, daylight, access for builders and material choices that sit comfortably with the existing street scene. On this project, the drawings needed to communicate not only the look of the extension but also how it would work technically: roof drainage, insulation build-ups, structural openings, floor levels and practical circulation through the home. That level of detail helps planning officers, Building Control and builders understand the proposal clearly, reducing avoidable questions and giving the homeowner a stronger basis for the next stage of their extension journey.
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