Garden annexes 25 to 35sqm
Between 25 and 35sqm, a garden annexe has room for a full kitchen and a proper sitting area, and towards the top of the range a separate bedroom. It is the size at which most people choose between a studio and a one-bedroom layout.
Illustrated from a scale model by The Garden Room & Annexe Guide.
In short
- Layout: a studio with a full kitchen from around 25–30sqm, or a compact one-bedroom annexe from around 30sqm.
- Shape: most are 6–9m long and 3.5–5m deep. A 6m × 4.8m building gives 28.8sqm.
- Cost: a compact one-bedroom annexe of 25–35sqm is typically advertised at £70,000–£85,000 for the building, and £85,000–£105,000 all-in.
- Planning: a self-contained annexe needs full planning permission with Building Regulations, or the Caravan Act route, built to BS3632 with a Lawful Development Certificate. See planning and the Caravan Act route.
Studio or one bedroom at 25 to 35sqm?
This is the range where a bedroom wall becomes possible. Below about 30sqm a separate bedroom tends to leave both rooms cramped; above it, a wall with a pocket door still leaves a comfortable living area.
- Studio with a full kitchen · 25–31 sqm
- One room for living, cooking and sleeping, with a full kitchen rather than a kitchenette. Garden Annexes’ 29.4sqm Ivyo 540 zones the room under a vaulted ceiling, and the owner of Garden Annexes’ 30.9sqm Annexxa 635 chose a sofa bed so the whole room is living space by day.
- Compact one-bedroom · from around 30 sqm
- A separate bedroom, a shower room and a kitchen-living area. Swift Unlimited’s 31.5sqm annexe in Dorset was designed for an autistic adult, and Ark Design Build’s 30sqm one-bedroom annexe uses an angled wall to fit an awkward garden.
- Multi-use · 30–35 sqm
- Some annexes at this size are used as an office or gym by day and guest accommodation at night, such as A Room in the Garden’s 34sqm office, gym and guest bedroom annexe.
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Annexes of 25 to 35sqm built by UK companies
Every annexe of 25 to 35sqm featured on The Guide, in a random order. Each one links to the full write-up, with the floor plan and the company that built it.
Garden Granny Annexe
This bespoke garden annexe features a spacious, self-contained layout, including a main living area with French doors, a well-equipped kitchenette, and a utility cupboard. The bedroom has an ensuite shower room with natural light from a Velux window and space-saving pocket doors.
Granny Annexe at the Bottom of the Garden
Annexe Spaces designed a compact 27.3m² granny annexe for an average-sized garden. The 4.37m x 7.5m structure includes an open-plan living area with kitchen, bedroom, and en-suite. Features like Cedral Click cladding and a composite decking path ensure low maintenance and accessibility.
Annexxa 635 by Garden Annexes: Open-Plan Living in a 31sqm Footprint
This Annexxa 635 by Garden Annexes packs open-plan living, a well-appointed kitchen, en-suite shower room and flexible sleeping into a 30.9sqm footprint. Wide-board cladding, shadow gap detailing, and a soft blue-grey palette make for a compact annexe with considered architectural character.
One-Bedroom Home at the End of the Garden
This one-bedroom garden home by Executive Garden Rooms provides a comfortable, self-contained living space at the end of the garden. Designed for an elderly family member, it includes a modern kitchenette, spacious shower room, and durable Cedral cladding for low maintenance.
Guest Bedroom in the Garden
Building a garden bedroom is an efficient alternative to a home extension. This 6m x 4.3m self-contained annexe by Executive Garden Rooms features an en-suite shower room, kitchenette, and high-spec finishes. Their turnkey service covers design, construction, and regulatory compliance.
Functional Self-Contained Garden Annexe
Swift Unlimited crafted this compact 27.88m² garden annexe with a separate bedroom, kitchenette, and living roof. Thoughtful design maximised space within boundary constraints, integrating storage and a Velux window for light. Completed in three weeks, it’s stylishly functional.
Vagabond Haven Elise: Self-Contained Tiny House Living
The Vagabond Haven Elise is a 25sqm self-contained tiny house with two sleeping lofts, a full oak-topped kitchen with dishwasher, and a proper wet-room bathroom. A Swedish company, newly entering the UK market, built to Scandinavian year-round standards.
Pitched Roof Granny Annexe
Annexe Spaces created a 31.2 sqm pitched-roof granny annexe with vaulted ceilings. The cottage-style exterior features cream render and grey accents. The interior includes a living room, kitchen, bedroom, and en-suite. This bespoke design offers independent living whilst maintaining family proximity.
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Frequently asked questions
- Is 30sqm big enough for a one-bedroom annexe?
- Yes, just. From around 30sqm a separate bedroom, a shower room and a kitchen-living area will fit, although the rooms are compact. Below that, most designers keep the layout open-plan so the space is not split into two small rooms.
- Should a 25–35sqm annexe be a studio or one bedroom?
- It depends on who lives there. A studio feels larger than its size and suits one person. A separate bedroom matters more for a couple who keep different hours, or for a carer staying over.
- How much does a 30sqm annexe cost?
- A compact one-bedroom annexe of 25–35sqm is typically advertised at £70,000–£85,000 for the building, with a realistic all-in budget of £85,000–£105,000 once any groundworks and connections not in the price are added. Whether VAT is included depends on the planning route.
Find annexe specialists that cover your area
The Garden Room & Annexe Directory lists UK annexe specialists, filtered by location, planning route and design approach.
Last updated October 2026 · Part of our garden annexe guide.
