Flexible multi-purpose garden annexe in Sheffield
An 8m x 4.5m SIPs annexe on a sloping Sheffield garden — guest room one week, creative retreat the next — clad in two textures of Millboard.
Heritage Living Group recently completed a bespoke garden annexe in Sheffield, designed as a comfortable year-round space to serve multiple uses. Working closely with their clients from the earliest design stages, the Heritage team developed 3D visuals and mood boards to ensure the finished building would be everything the couple envisaged.
The 8m x 4.5m building was created as a multi-purpose annexe-part guest accommodation, part creative retreat. With a generous living space, stylish kitchenette, and modern shower room, the building offers a self-contained environment while maintaining a strong connection to the surrounding garden.
At a glance
- Size: 8m x 4.5m — a generous living space with a sofa bed, a kitchenette and a modern shower room.
- Built for: a couple who wanted part guest accommodation, part creative retreat, designed from 3D visuals and mood boards.
- Construction: SIPs floor, walls and roof on ground screw foundations, with matching steps up to the door on the sloping site.
- Outside: vertical Burnt Cedar and horizontal Coppered Oak Millboard, aluminium bi-folds, a glazed side door and a square black-framed window.
- Inside: plastered and painted walls, underfloor heating, LVT flooring, black switches and sockets; a Doncaster team working across Yorkshire.
Built with SIPs for year-round comfort
As with all Heritage Living Group projects, this annexe was built with Structural Insulated Panels (SIPs) for the floor, walls, and roof. At the heart of a multi-layer build-up, SIPs form a robust core structure and, when paired with house-quality doors and windows, create a highly insulated envelope that makes the space comfortable to use in all seasons.
The annexe sits on ground screw foundations, a system well-suited to the slightly sloping site. This approach minimises groundworks while ensuring the building remains stable and level. The Heritage team carefully detailed the cladding to follow the contours of the site and constructed a set of matching steps up to the entrance.
Millboard cladding adds texture and depth
Externally, the annexe features Millboard composite cladding, chosen for its durability and low maintenance. Two different Millboard finishes were combined to create texture and visual depth.
- Burnt Cedar Batten and Board – installed vertically, this premium cladding replicates the look of charred timber created with the Shou Sugi Ban technique. As real timber is used in the moulding process, it captures the authentic tones and grain of natural cedar.
- Coppered Oak Decking Boards – installed horizontally on the opposite elevations, these boards provide a softer contrast.
The crisp intersection between vertical Burnt Cedar and horizontal Coppered Oak, along with the mix of tones, board directions, and textures, has resulted in a striking yet balanced exterior.
Glazing enhances indoor-outdoor living
A large set of aluminium-framed bi-fold doors connects the main living space with the garden. The sofa, which converts into a bed, has been positioned to maximise the view through these doors. At the opposite end of the room, a glazed side door by the kitchenette frames another garden aspect and offers convenient everyday access. A square opening window on the front wall completes the glazing, its black frame pairing smartly with the Burnt Cedar cladding.
High-spec interior finish
Inside, the annexe has been finished to house-like standards with plastered and painted walls, underfloor heating, and durable LVT flooring laid over marine ply. The kitchenette includes a sink, under-counter fridge, and storage, while the modern shower room has been fitted with the clients’ choice of sanitaryware and tiles. Premium black switches and sockets add to the refined finish.
Turnkey service in Yorkshire
Heritage Living Group handled every stage of this project, including final service connections, as part of their turnkey service. Based in Doncaster, they focus their attention on projects across Yorkshire, offering a bespoke design process supported by detailed 3D modelling and careful material selection.
Learn more about Heritage Living Group
If you’d like to know more about this project, reach out to Heritage Living Group by calling 01709 865 392 or emailing hello@heritageliving.co.uk. You can also head over to their website to learn more about their services and try their design tools to start shaping your own garden annexe ideas.
