Garden Annexes 35sqm to 45sqm in Size
Updated: 9 March 2026
On this page, we are featuring garden annexe projects between 35 and 45 square metres in size. This footprint range offers a lot of flexibility in terms of layout, providing more room to create a highly functional living space. As you explore these examples, you’ll see that some annexes use open-plan layouts, where one large room accommodates eating, sleeping, and living spaces alongside an en-suite bathroom. Others are one-bedroom annexes, offering more defined separation between the sleeping area and the main living space. Some designs in this size range even include two bedrooms alongside a central living area, providing even more versatility for family living or guest accommodation.
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Each project showcased here has been tailored to meet the owner’s specific requirements and the available space in their garden. Some of these annexes serve as guest accommodation with en-suite facilities, while others offer self-contained living spaces for a relative seeking independent living while staying close to the main house.
These garden annexes have been designed to comply with either Full Planning Permission and Building Control regulations for permanent residences, or have been classified as mobile homes under the Caravan Act. In the latter case, a Lawful Development Certificate confirms their legal status, ensuring compliance with all necessary regulations for use as independent living spaces.
We hope these projects inspire you and show the potential for creating flexible, spacious living environments within this footprint range. The projects are listed by size, from smallest to largest.
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This page looks at annexes between 35sqm and 45sqm:
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This 35.1 sqm garden room, designed by Executive Garden Rooms, offers a versatile living space tailored to suit the needs of the whole family. Measuring 7.8m by 4.5m, the room includes a well-specified shower room and kitchenette, making it ideal for guests. A half-height wall zones the space into distinct areas for relaxation, work, and entertainment while maintaining an open-plan feel. Discreet fitted furniture enhances functionality. Executive Garden Rooms handled every aspect of the project, from planning to final utility connections, ensuring compliance with Planning and Building Control regulations, including those for a Conservation Area.
This 36 sqm one-bedroom granny annexe, designed by Executive Garden Rooms, provides a spacious, self-contained home with a well-equipped kitchen—ideal for a keen cook. Measuring 8m x 4.5m, the annexe includes a bedroom with an en-suite shower room and an open-plan living area with an L-shaped kitchen featuring an oven, induction hob, and integrated fridge. The light-filled living space benefits from large sliding doors and a Velux window with rain sensors. Externally, the annexe is clad in a mix of Western Red Cedar and dark grey Cedral for a stylish, low-maintenance finish. Executive Garden Rooms provided a full turnkey service, managing planning, construction, and utility connections.
This 36 sqm one-bedroom garden annexe, designed by Swift Unlimited, provides a customised living space for a client moving in with family. The L-shaped layout includes a well-specified kitchen, a spacious living area with bi-folding doors, and a double bedroom with built-in storage. High-spec finishes, such as underfloor heating and pocket doors, enhance functionality. The exterior is clad in Larch tongue-and-groove for low maintenance. Swift Unlimited managed the entire process, from design and Planning Approval to construction and utility connections, delivering a fully commissioned annexe.
This 37.5 sqm garden annexe by Ark Design Build demonstrates how a modern, high-spec studio apartment can be seamlessly integrated into a long garden setting. Centrally positioned within the garden, the annexe benefits from garden views on both sides, with two sets of bi-fold doors allowing plenty of natural light. The open-plan space includes cleverly designed fitted furniture that defines living, dining, and sleeping areas, alongside a compact kitchen and shower room. Key features include integral blinds, external downlights, and space for a future wood burner. Ark Design Build handled the entire project, from planning to final connections.
This 37.9 sqm garden annexe, designed by Swift Unlimited, combines the functionality of a home office with the flexibility of guest accommodation. Measuring 8.15m by 4.65m, the building features extensive glazing, including large powder-coated aluminium sliding doors that create a striking corner of glass, connecting the interior with the garden. Fully complying with Building Regulations, the space doubles as a comfortable guest bedroom when needed. The annexe has an overall height of 2.9m, meeting the client’s vision for a taller, light-filled space.
This 38.28 sqm open-plan garden annexe, designed by Miniature Manors, offers a contemporary living space seamlessly connected to its rural Surrey surroundings. Measuring 8.7m by 4.4m, the annexe features black and oak Millboard cladding, creating a modern, barn-like appearance. Inside, the open-plan layout includes a bespoke Shaker-style kitchen with a picture window framing garden views, and a spacious shower room. Two sets of corner bi-fold doors connect the living area to the garden, enhancing the indoor-outdoor flow. Miniature Manors managed the entire project, from Planning Approval to final connections.
This 40 sqm garden annexe, designed by Timeless Garden Rooms, is a versatile retreat built with teenage independence in mind. Featuring a spacious main room, kitchenette, shower room, and a sleeping deck, this annexe serves as both a private hangout and guest accommodation. The asymmetrical roofline adds character while complying with planning requirements. Clad in weatherboard and Western Red Cedar shingles, the annexe blends seamlessly into the garden, with three sets of French doors connecting the indoors to the outdoors. Timeless Garden Rooms provided a full turnkey service, from design to Building Control sign-off.
This 40 sqm one-bedroom garden annexe by Swift Unlimited was designed to provide a modern, accessible home for an older relative. Featuring a spacious living area with bi-fold doors, a well-equipped kitchen, and a double bedroom with an en-suite shower room, the annexe is both stylish and functional. Built with SIPs panels for excellent insulation, it ensures year-round comfort and energy efficiency. Swift Unlimited managed the entire project, from design and planning approval to final utility connections, delivering a fully move-in-ready home in just four weeks.
This 40 sqm SIPs granny annexe, designed by Annexe Spaces, provides a self-contained, light-filled home for a family in Scotland. Measuring 8m by 5m, the one-bedroom annexe features an open-plan living area with large French doors and high-opening windows, creating a bright and airy space. The well-equipped kitchen and contemporary shower room add to the home's comfort and functionality. Built using Structural Insulated Panels (SIPs), the annexe benefits from excellent insulation, ensuring year-round comfort with low energy costs. Annexe Spaces managed all aspects of the project, including Planning, Building Control, and utility connections.
This 40 sqm one-bedroom garden annexe, designed by Executive Garden Rooms, provides a modern, independent living space for the clients' son. Measuring 8m by 5m, the annexe features an open-plan living area with a well-equipped kitchen, a spacious double bedroom, and an en-suite shower room. Built 60 metres from the main house, the project required extensive groundworks, including a reinforced foundation and trenching for utilities. The light-filled annexe includes French doors, floor-to-ceiling windows, and a well-specified electrical package. Executive Garden Rooms managed the entire process, from design to Planning and utility connections.
This 41 sqm mobile home, designed by A Room in the Garden, fits perfectly into an irregularly shaped garden, maximising living space without compromising the garden's layout. Built under the Caravan Act, the wedge-shaped structure features a concave front elevation with a combination of treated Redwood and white render. Inside, the annexe includes a well-proportioned kitchen and living area, a double bedroom, and a stylish shower room. A large skylight fills the living space with natural light, and oak-effect flooring with underfloor heating adds warmth and comfort. A Room in the Garden managed the entire project, tailoring every detail to the client's preferences.
This 42 sqm one-bedroom annexe in Tunbridge Wells demonstrates Ark Design Build's expertise in overcoming challenging sites and creating bespoke, habitable spaces. Designed for a sloped garden, the annexe sits on a groundscrew foundation cleverly concealed with black Thermowood cladding. Its contemporary barn-style design features a dual-pitched roof, standing seam metal roofing, and a decked veranda that contrasts beautifully with the dark exterior. The vaulted ceiling, remote-controlled roof windows, and bi-fold doors flood the living space with natural light, enhancing the treehouse-like atmosphere. A well-appointed kitchen, spa-like bathroom, and air conditioning system ensure year-round comfort in this turnkey project.
This 44 sqm two-bedroom holiday lodge, built by JML Garden Rooms in St Andrews, replaces an old garage and provides a stylish, high-spec annexe ideal for hosting family or renting to holidaymakers. Constructed using energy-efficient Structural Insulated Panels (SIPs), the lodge is designed for year-round comfort and low running costs. JML Garden Rooms managed the entire project, delivering a durable and attractive space that has become a valuable source of income for the owners. This project highlights JML’s expertise in bespoke design and SIPs construction, ensuring both efficiency and style.