Two-bedroom granny annexes: layouts, floor plans and cost
A two-bedroom granny annexe is a self-contained home in the garden with two separate bedrooms, a living area, a full kitchen and at least one bathroom. The second bedroom is what sets it apart: room for a couple who sleep apart, a live-in carer, visiting family or a hobby. Across the projects on this page, two-bedroom annexes run from 41sqm to 95sqm.
Illustrated from a scale model by The Garden Room & Annexe Guide.
In short
- Layout: two separate bedrooms, a living area, a full kitchen and one or two bathrooms. It is the size of a small bungalow and is lived in like one.
- Size: most are between 50sqm and 70sqm. The smallest on this page is 41sqm and the largest 95sqm.
- Cost: budget around £125,000–£160,000 or more for the building, and £140,000–£180,000 or more once groundworks and connections are added.
- Planning: it needs the same consent as any annexe: full planning permission, or the Caravan Act route with a Lawful Development Certificate. Under the Caravan Act, the building must fit within 20m × 6.8m and be built in no more than two sections.
Who is a two-bedroom annexe for?
The second bedroom changes who the annexe can house. A one-bedroom annexe suits one person, or a couple who share a room. Two bedrooms open it up to a wider set of arrangements.
A couple who need to sleep apart
Because of illness, a care bed, or different hours.
A parent with a live-in carer
Where the carer needs a room of their own nearby.
One person who wants a real spare room
For family visits, a grandchild staying over, or a hobby. In one of the projects below, the second bedroom doubles as a sewing room.
Two young adults or teenagers
Each with their own room and a shared kitchen and living space.
Holiday accommodation
Two bedrooms make an annexe practical to let to a family or two couples. Timeless Garden Rooms built one of the projects below for family visits and Airbnb stays, with full planning permission and Building Regulations sign-off. Letting has to be made clear in the planning application (see Planning).
Whoever it is for, a two-bedroom annexe is used as a full home. The occupants cook, eat and spend the day in it, so the kitchen, storage and bathrooms need to be planned for full-time use by two people.
Two-bedroom annexes built by UK companies
Every two-bedroom annexe featured on The Guide, in a random order. Most were built as permanent homes with full planning permission and Building Regulations sign-off; others were supplied under the Caravan Act with a Lawful Development Certificate.
95sqm Residential Annexe in Essex by SIPS Garden Rooms
A 95sqm residential annexe in Essex by SIPS Garden Rooms, giving a family member an independent home steps from the house. Two large bedrooms under a mono-pitch living roof, two air source heat pumps, and delivered turnkey in eight weeks.
Two-Bedroom Garden Annexe for Airbnb Rental
Timeless Garden Rooms designed this two-bedroom garden annexe for Airbnb rental, blending charm with functionality. Featuring a Cedar shingle roof, spacious veranda, energy-efficient insulation, and contemporary interiors, it provides a year-round retreat with potential for income generation.
Contemporary 2-Bedroom Garden Annexe
Annexe Spaces crafted a 60.86sqm garden annexe featuring two bedrooms, a shower room, and an open-plan living area with kitchen. The contemporary design incorporates ample glazing, white rendered frontage, and Anthracite Grey accents. Ground screws enabled construction on sloped terrain, creating a versatile, cost-effective living solution.
Two-Bedroom Accessible Garden Annexe by Vita Modular
This 55sqm two-bedroom garden annexe in Reading by Vita Modular pairs a standing seam metal roof and vertical timber cladding with black aluminium glazing to every room. Designed around accessibility, it delivers a self-contained, step-free home for year-round living.
12m x 5m Two Bedroom Granny Annexe
Timeless Garden Rooms designed this 12m x 5m granny annexe with two bedrooms, a vaulted living area, and a shower room. Featuring underfloor heating, wheelchair-accessible doors, and a veranda, it offers independence, comfort, and thoughtful futureproofing for elderly family members.
85sqm Two-Bedroom Garden Annexe
This 85sqm two-bedroom garden annexe by Timeless Garden Rooms provides a self-contained, adaptable living space for older relatives. Featuring two en-suite bedrooms, an open-plan kitchen and living area, and a covered veranda, it offers independence, comfort, and proximity for family care.
Suffolk Barn Living Space by Smart Modular Buildings
Smart Modular Buildings created this Suffolk Barn living space for a family who needed more room without moving. Inspired by Suffolk architecture, the vaulted design, light-filled interior and flexible layout make this a modern annexe you want to spend time in.
Contemporary Two Bedroom, Two Bathroom Garden Annexe
A Room in the Garden created a bespoke two-bedroom, two-bathroom garden annexe under the Mobile Home Act. This high-spec, low-maintenance home features a modern design with crittall-style doors, corrugated metal cladding, and thoughtful details throughout. It offers comfortable, stylish living for downsizing retirees.
How big is a two-bedroom granny annexe?
Most two-bedroom annexes are between 50sqm and 70sqm, and a comfortable size for two double bedrooms, a living-kitchen and one bathroom is around 55–60sqm. Below 50sqm it can be done, but something gives: usually the second bedroom, the kitchen, or the living space.
| Footprint | Project | Layout |
|---|---|---|
| 41 sqm8.3m × 6m | Vagabond Haven Evergreen | Double and single bedroom, one wet room |
| 44 sqm | JML Garden Rooms, St Andrews | Two double bedrooms |
| 55 sqm11m × 5m | Vita Modular, Reading | Two doubles, en-suite plus family bathroom |
| 60 sqm12m × 5m + pod | Timeless Garden Rooms | Two bedrooms, shower room in a rear pod |
| 60.86 sqm8.95m × 6.8m | Annexe Spaces | Two bedrooms, one shower room |
| 65 sqm | A Room in the Garden | Two bedrooms, two bathrooms, dressing room |
| 70.78 sqmL-shaped | AMC Garden Rooms, Hertford | Two doubles, shower room, utility room |
| 85 sqmL-shaped | Timeless Garden Rooms | Two bedrooms, each with an en-suite |
| 95 sqm | SIPS Garden Rooms, Essex | Two large bedrooms, accessible wet room plus bathroom |
Two-bedroom projects on The Guide, by footprint.
The smallest, Vagabond Haven’s Evergreen, fits two bedrooms into 41sqm by making the second one a single, with a desk and an armchair. It is the only two-bedroom annexe we have featured at that size. Timeless Garden Rooms’ 85sqm annexe gives each bedroom its own en-suite and still has room for a dining table in the kitchen. The largest, SIPS Garden Rooms’ 95sqm annexe in Essex, has more floor area than the national space standard sets for a two-bedroom, four-person home, with an accessible wet room as well as a separate bathroom.
Footprint and floor area are not the same. Annexe sizes are almost always quoted as the external footprint. Residential walls are thick, so the usable floor inside is typically 15–20% smaller. When comparing a floor plan with a price list, check which figure each one uses.
Garden width matters as much as area. A two-bedroom annexe is long. Most of the projects above are 5–7m deep and 9–12m long, so the question is often whether the garden can take the length. Many modular ranges step up in 500mm increments, and bespoke designers can work to the exact space available, which helps on plots that are not a simple rectangle.
What does a 2 bedroom granny annexe floor plan look like?
In a two-bedroom annexe the floor plan comes down to how the two bedrooms relate to each other and to the shared living space. The projects on this page use five arrangements.
- Bedrooms in a line, each opening onto a verandaThe living area sits at one end and the bedrooms run along the building beside it, each with its own French doors to the garden. The veranda becomes the corridor as well as a seating area. Timeless Garden Rooms’ 12m × 5m annexe uses this plan, with the shower room in a small pod at the back so that it takes no length from the main building. It is the most economical arrangement on a long, narrow plot.
- Bedrooms along the garden side, bathrooms behindA variation on the line: the bedrooms and the living-kitchen share the garden side of the building, and the bathrooms, storage and utility sit in a strip along the back, reached from an internal hallway. Every habitable room gets the view and its own glazed doors, and the rooms that need no view take the darker side. A Room in the Garden’s 65sqm two-bedroom, two-bathroom annexe is laid out this way, with both bathrooms, a dressing room and a utility room along the back wall and the living-kitchen across the far end.
- Bedrooms together at one endBoth bedrooms and the bathroom sit at one end and the living-kitchen at the other, which keeps the private and shared zones separate. Vita Modular’s 55sqm annexe in Reading is arranged this way, with the main bedroom’s en-suite and the family bathroom between the two rooms. It suits a couple, or a parent and carer who want to be within earshot of each other at night.
- Bedrooms at opposite endsThe living space sits in the middle, with a bedroom off each end. This gives the most privacy between the two rooms, and suits two adults who keep different hours or a relative with a live-in carer who needs time off duty. In the 85sqm Timeless annexe, both bedrooms branch off the central living area and each has its own en-suite.
- An L-shapeAn L-shaped plan separates the zones without a corridor. In AMC Garden Rooms’ 70.78sqm annexe for two teenagers, the two double bedrooms and the shower room sit in one arm, and the living space runs along the narrower wing, with windows on two sides.
A few layout points that recur
- The kitchen and bathroom need water and drainage, and they are the hardest things to move once the design is fixed. Placing them back to back, as Annexe Spaces did with the shower room and kitchen in their 60.86sqm annexe, shortens the pipe runs.
- Where the bedrooms open straight off the living room, sound carries. A short lobby or the bathroom between the two bedrooms helps.
- Think about which room gets the view. In most annexes the living area faces the garden and the bedrooms get a side window. Vita Modular’s Reading annexe gives both bedrooms full-height glazing and sliding doors to the garden.
One bathroom or two?
One shower room is enough for two people who share a household, and it leaves more of the floor for living space. Annexe Spaces’ 60.86sqm annexe has a single 2.3m × 1.8m shower room with a pocket door, next to the kitchen.
A second bathroom earns its space when both bedrooms are in use at the same time by people who are not a couple: a parent and carer, two young adults, or family who stay regularly. There are three ways to add one:
- An en-suite plus a family bathroomThe main bedroom has its own en-suite, and a second bathroom serves the other bedroom and visitors. Vita Modular’s Reading annexe works this way.
- Two en-suitesEach bedroom has its own bathroom, with no shared one. Timeless Garden Rooms’ 85sqm annexe uses pocket doors on both, so no floor is lost to a swinging door.
- Two full bathrooms and a dressing roomA Room in the Garden’s 65sqm retirement home at the end of the owners’ garden has both, with crittall-style sliding doors between rooms that open the plan up during the day and close for privacy.
Designing a two-bedroom annexe for a live-in carer
When the second bedroom is for a carer, the two rooms have different jobs, and the layout should reflect that.
If one bedroom is for a carer
Size the main bedroom around the equipment rather than the bed. In Timeless Garden Rooms’ turnkey two-bedroom annexe, the main bedroom was made large enough for a specialised medical bed and the second bedroom smaller, for a live-in carer. The family also asked for it not to feel clinical, and French doors with sidelights keep the view of the garden from inside. Think about how close the two rooms need to be at night, and whether the carer needs a bathroom of their own. If an occupational therapist is involved in the occupant’s care, their recommendations can be written into the brief.
Left: the main bedroom in the split plan, with clear floor around the bed and an armchair by the doors to the garden. Right: the second bedroom at the other end of the annexe, opening off the kitchen. Illustrated from a scale model by The Garden Room & Annexe Guide.
Accessibility is easier to design in than to add later. Vita Modular designed their Reading annexe around mobility needs from the start: step-free access, flush thresholds, wider doorways, wheelchair turning space, an accessible bathroom with a walk-in shower, walls reinforced for grab rails and kitchen worktops considered for seated use. Where accessibility is not needed yet, it can still be allowed for. Timeless Garden Rooms’ 12m × 5m annexe was built with wider doors and a ramp up to the veranda so that it will work with a wheelchair later.
Details that matter in a two-bedroom annexe
- A full kitchenA two-bedroom annexe is a full-time home, so a full kitchen is the starting point: worktop, storage and appliances for two people. AMC Garden Rooms fitted an L-shaped kitchen with a full-height fridge and a four-ring hob in their Hertford annexe. Vagabond Haven’s compact Evergreen still includes a dishwasher, which is usually the first thing dropped in a small annexe.
- Ceiling heightA pitched roof gives a vaulted ceiling over the living space, which makes a long building feel less like a corridor. Timeless Garden Rooms’ 12m × 5m annexe, Vagabond Haven’s Evergreen and Smart Modular Buildings’ Suffolk Barn annexe all use one. Raise ceiling height early; it is straightforward to design in and very difficult to change later.
- A covered verandaOn a long building, a veranda along the garden side links the rooms outside as well as in. Three of the Timeless annexes on this page have one, and in their 85sqm annexe every room has a door onto it.
- StorageTwo people living full time need more storage than a one-bedroom plan allows for: a wardrobe in each bedroom, a full-height kitchen unit, somewhere for coats and shoes by the door, and outdoor storage for garden items or a mobility aid. AMC Garden Rooms’ Hertford annexe adds a separate utility room.
- HeatingUnderfloor heating keeps the walls clear for furniture and wardrobes. Timeless Garden Rooms’ 12m × 5m annexe has it throughout, and in a building with two bedrooms and a long run of rooms, that means no radiators to plan around.
Buying a two-bedroom annexe: ready-made range or bespoke?
When people search for a two-bedroom annexe “for sale”, almost all of what they can buy is new: a model from a company’s range, or a bespoke design. Second-hand annexes do come up, but rarely, and they are usually ones built under the Caravan Act, where the building is designed to be moved. An annexe built with full planning permission is fixed to its site and is sold with the house.
A range model starts from a set of standard sizes with a published price, which makes it easier to budget. Garden Annexes offer four ranges, the Annexxa, XB, St George and Ivyo, each in 24 sizes, and recommend two-bedroom layouts in eight of those sizes across all four ranges. The size is the fixed part. Inside, the layout is configured around the garden and the people living there, including where the bedrooms, en-suites, doors and windows go.
A bespoke design is drawn from scratch around the garden and the people who will live in it. A Room in the Garden design larger, multi-bedroom annexes this way. Their 65sqm annexe on this page started from a floor plan the clients brought to them, which the team developed with them into two bedrooms, two bathrooms and a dressing room. Timeless Garden Rooms work the same way: they drew up three different plans for the family behind the 12m × 5m annexe before they chose one.
Either way, the price of the building is only part of the cost. Connections to the house, groundworks where they aren't included and, on the full planning route, VAT all sit on top.
How much does a 2 bedroom granny annexe cost?
For a two-bedroom annexe, building prices run from around £125,000 to £160,000 or more, and up to about £190,000 on the full planning route. Where they aren't included, groundworks and utility connections usually add £15,000–£20,000 or more at this size, and a realistic all-in budget is £140,000–£180,000 or more. As a real reference point, a 48sqm two-bedroom annexe from Swift Unlimited was supplied at £118,500 for the building, before groundworks, connections or site preparation.
- One-bedroom · typically 31–55 sqm
- Building prices of £70,000–£120,000; £85,000–£140,000 with groundworks and connections.
- Two-bedroom · typically 50–85 sqm
- Building prices of £125,000–£160,000 or more; £140,000–£180,000 or more with groundworks and connections.
Figures from real projects and 267 published prices from 13 UK annexe specialists, checked October 2026. Whether VAT is included depends on the planning route.
The planning route affects the price as much as the size does. A two-bedroom annexe built to BS3632 and supplied under the Caravan Act may be zero-rated for VAT, while the same building on the full planning route carries 20%. On a £120,000 building, that is £24,000. A Room in the Garden’s 65sqm two-bathroom annexe was supplied under the mobile home rules for that reason. Annexe by Future Rooms shows the difference more clearly than most, because it publishes the price of each model on both routes. Its Welland large two-bedroom is £154,400 built to BS3632, with VAT at 0%, and £191,280 built to Part L of the Building Regulations: £159,400 for the building plus £31,880 VAT. Before comparing quotes, check what each includes and whether VAT is in the figure.
Does a two-bedroom annexe need planning permission?
Yes. A two-bedroom annexe has its own kitchen, bathroom and bedrooms, so it cannot be built under Permitted Development. There are two routes.
- Full planning permission with Building RegulationsThe annexe is approved as a permanent building, with no limit on its size or shape beyond what the local authority will accept. Most of the larger annexes on this page, including Timeless Garden Rooms’ 85sqm L-shape, were built this way.
- The Caravan Act routeThe annexe is built to BS3632, the residential mobile home standard, as a twin-unit caravan, and its siting is confirmed with a Lawful Development Certificate. The building must fit within 20m long and 6.8m wide, with an internal height of no more than 3.05m, and be built in no more than two sections. Most two-bedroom layouts fit inside those limits; a two-section build makes an L-shape much harder.
If the annexe will be let
A holiday let needs full planning permission for that use, and it has to be made clear in the application from the start. An annexe approved for family use is usually tied to the main house, often by a planning condition, and letting it later can need a fresh application. Timeless Garden Rooms’ Airbnb annexe went through planning in a conservation area, with conditions to protect the trees on site, and was signed off by Building Control. The Caravan Act route does not suit a let, because the annexe has to stay in use with the main house.
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Frequently asked questions
- How big is a 2 bedroom granny annexe?
- Most two-bedroom granny annexes are between 50sqm and 70sqm. Around 55–60sqm is comfortable for two double bedrooms, a living-kitchen and a bathroom. The projects on The Guide range from 41sqm, with a single second bedroom, to 95sqm with an accessible wet room and a separate bathroom. Sizes are usually quoted as the external footprint.
- How much does a 2 bedroom granny annexe cost?
- Building prices for a two-bedroom annexe typically run from £125,000 to £160,000 or more. With groundworks and utility connections, a realistic all-in budget is £140,000–£180,000 or more. Whether VAT is included depends on the planning route, so check each quote.
- Can you buy a 2 bedroom granny annexe ready-made?
- Mostly, a two-bedroom annexe is bought new. Some companies offer ranges in standard sizes with published prices and a layout configured to suit you; others design bespoke. Second-hand annexes are rare and are usually Caravan Act buildings, designed to be moved. Connections, approvals and, where they aren't included, groundworks are added to the price of the building.
- Can a two-bedroom annexe be used as a holiday let?
- Yes, with full planning permission for that use, made clear in the application. An annexe approved for family use is usually tied to the main house, and the Caravan Act route requires the annexe to stay in use with it, so neither can simply be let later.
- Can a two-bedroom annexe be built under the Caravan Act?
- Yes, if it is built to BS3632 in no more than two sections and fits within 20m × 6.8m, with an internal height of no more than 3.05m. Its siting is confirmed with a Lawful Development Certificate, and it must be used in connection with the main house.
- Does a two-bedroom annexe need two bathrooms?
- Not necessarily. One shower room works for a couple or one person with a spare room. A second bathroom, or an en-suite, is worth considering when both bedrooms are used at the same time by people who are not a couple, such as a parent and a live-in carer.
- What is the smallest two-bedroom granny annexe?
- The smallest on The Guide is Vagabond Haven’s Evergreen at 41sqm, with a double bedroom, a single second bedroom, a full kitchen and a wet room. Most two-bedroom annexes are larger, from around 50sqm.
Illustrated from a scale model by The Garden Room & Annexe Guide.
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The Garden Room & Annexe Directory lists UK companies that build two-bedroom annexes, filtered by location, planning route and design approach.
Last updated October 2026 · Part of our garden annexe guide.
