House Extensions Hampshire
Want more living space without the upheaval of moving? rob leary architecture designs house extensions across Hampshire, taking you from first ideas through to approved drawings. Our expert team creates extensions that add value, improve light and flow, and satisfy your local planning authority, all on a fixed fee with clear timelines and professional advice throughout.
Extension ideas That Suit Hampshire homes
Every street in Hampshire has its own character, from Victorian terraces in Winchester to 1930s semis in Southampton and modern estate houses in Basingstoke. We design each extension so it looks like it always belonged.
A single-storey extension is the most popular route to an open-plan kitchen-diner. We shape the plan around daylight, circulation and storage so the new space works every day. Side return extensions widen narrow kitchens, while wraparound layouts combine side and rear areas for a more generous ground floor.
For growing families, double-storey extensions can add a larger kitchen below with a bedroom, study or en suite above. Two-storey work needs careful massing and material matching to keep the street scene balanced.
Orangeries pair solid piers with high-performance glazing to create a bright, thermally stable room. Loft conversions add a bedroom or home office without expanding your footprint, and we often align a ground-floor extension with a future loft so you can extend in phases.
Inside, we plan structural openings for long sightlines and position rooflights and doors so the finished home extension feels calm, bright and practical.
Planning permission and permitted development Across Hampshire
Many house extensions proceed under permitted development, but the rules are precise and your local planning authority will expect every criterion to be met. Our drawings evidence compliance, so you can move forward with confidence.
Together, extensions and outbuildings must not cover more than half of the land around the original house. A single-storey extension must not project forward of the principal elevation facing a highway, and anything taller than four metres will need planning permission. Two-storey proposals generally require a full application.
Permitted development rights are often restricted in Conservation Areas and Areas of Outstanding Natural Beauty, and some properties carry Article 4 Directions. We check all of this at the outset.
We prepare and submit your planning application or permitted development documentation, liaise with case officers and adjust drawings in response to consultee comments. Where full permission is needed, we address scale, overlooking, overshadowing, and materials early, giving the application the best possible footing.
Building regulations and party wall matters
Building regulations approval is required for structural extensions. We produce building regulations drawings covering structure, insulation, fire safety, drainage, ventilation and access, including load paths, lintel sizing, thermal junctions and airtightness.
We coordinate with building control and your structural engineer so details are buildable and clearly shown, which reduces questions on site and speeds up inspections.
If your building work sits near a boundary or shared structure, the Party Wall Act 1996 is likely to apply. We advise on when a party wall notice is required, help you brief a surveyor, and flag practical matters such as drainage diversions and underpinning early.
What does a house extension cost?
The cost of a house extension depends on size, specifications, and complexity. In Hampshire, a well-specified single-storey extension often costs around £2,000 to £3,000 per square metre for a fully finished space, with shell-only figures lower.
How much do builders charge for an extension?
Most builders offer fixed price quotes based on clear drawings and a specification. Labour and materials make up the bulk of the figure, with preliminaries, waste removal, scaffolding, and building control fees on top. Expect higher rates for complex groundworks, restricted access or premium glazing.
What is the average cost of a house extension in the UK?
Market guides commonly suggest £2,000 to £3,000 per square metre for a finished single-storey space. Two-storey extensions often cost less per square metre because foundations and roof are shared, although the total project sum is higher.
How much does a 3 metre by 3 metre extension cost?
A compact 3m by 3m addition might be quoted anywhere between £25,000 and £60,000, depending on foundations, glazing choices, access and finishes.
Is 40k enough for an extension?
For a small, straightforward single-storey addition with standard finishes and good access, £40,000 can be feasible. Premium kitchens, complex steelwork or extensive internal alterations will push the total beyond it.For a small, straightforward single-storey addition with standard finishes and good access, £40,000 can be feasible. Premium kitchens, complex steelwork or extensive internal alterations will push the total beyond it.
Can I build an extension for 20k?
That budget is very tight in the current market. It may stretch to a very small shell or minor alterations, with significant DIY input and basic finishes.That budget is very tight in the current market. It may stretch to a very small shell or minor alterations, with significant DIY input and basic finishes.
What is the 3 metre rule for extensions?
For many attached houses under permitted development, the rear projection limit without prior approval is three metres from the original rear wall. Six metres on semis and eight metres on detached homes may be possible through the neighbour consultation scheme, where the criteria are met.
What is the 50% rule for house extension?
Your additions must not cover more than half the land around the original house, and outbuildings count towards that calculation. We review the entire plot and any prior work before advising. When comparing quotes, ask every builder to price the same drawings and schedule of works, then confirm what is included for foundations, drainage, insulation, glazing, electrics, plumbing and finishes.
Our fixed-fee design packages
Clear pricing helps you plan. Our Standard package starts from £1,950 + VAT and covers a measured survey, detailed planning drawings and submission. The Premium package is £2,950 + VAT and adds enhanced documentation and tender assistance.
Additional storey design starts from £750 + VAT, and loft conversion design from £950 + VAT where it forms part of a wider scheme. Planning application fees are paid directly to the local authority, and we will advise whether permitted development or full planning permission is the right route for your property.
How the design process works
We begin with a friendly consultation, listening to your goals, reviewing your home and mapping the likely permissions and timescales.
Next comes the survey and concept. We measure, photograph and assess structure and services, then test early layouts to prove the brief before anything is fixed.
At the planning stage, we produce clear drawings, submit them and manage the conversation with your local authority. Once approved, we prepare detailed building regulations drawings and support your building control route, whether that is via the council or an approved inspector.
Before construction, we help you approach builders so each one prices the same information, guide you through any party wall notices and coordinate with your structural engineer. During the build, we remain available to answer questions and ensure the drawings are being followed.
Local knowledge and an experienced team
Since 2012, we have completed more than 150 residential projects across Hampshire. Our experienced team understands district policies and the practical expectations of local case officers, which shapes the professional advice we give on massing, privacy, and materials.
We work on everything from small kitchen additions to two-storey schemes and complex wraparounds, covering feasibility, planning, technical design and tender support, so your project stays coherent from first sketch to completion.
Frequently Asked Questions
Yes. We are based in Basingstoke and regularly work across Hampshire, including Winchester, Eastleigh, Southampton, Portsmouth, Andover, Fleet and the surrounding villages.
We are architectural designers. The title architect is protected in the UK for those registered with the Architects Registration Board, and we do not use it.
Yes. We prepare and submit your planning application or permitted development documentation, liaise with the local planning authority and adjust drawings where required.
A typical domestic planning decision can take up to eight weeks after submission, with time beforehand for survey, design, and your feedback rounds, then further time afterwards for building regulations drawings and tendering.
Start your Hampshire house extension
Speak to rob leary architecture about house extensions in Hampshire. Request a fixed-fee proposal and start planning for more living space with a trusted local team. Our house extension services are ideal for renovating your existing property, meaning you don’t need to go through the stress of moving home. With our high-quality house extensions and your house extension aspirations, we can create the perfect additional space for you and your family.