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Studio Ben Allen completes self-build geometric flatpack garden folly

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Using prefabricated geometric interlocking parts, the garden folly has been designed for assembly, disassembly and re-assembly

’A Room in the Garden’ provides space for family members – including two young children – to work, sleep or read away from the main family home: a garden flat in Putney, south-west London.

Designed for self-build assembly and disassembly, the product comes as a flatpack kit of parts which has been fabricated using a CNC machine. It uses materials with low VOC in assembly and use, and can be demounted and re-erected when needed.

Each element has been numbered, fixing holes pre-drilled and slots created, to eradicate the need for onsite cutting. Each piece has been cut using readily available digital fabrication – cut and notched to interlock smoothly.

A room in the garden 20190517 021 original

The structure uses a geometry of changing forms with an octagonal wall structure rising to form a hexagonal roof which frames a vertical skylight. Timber columns supporting the walls converge to form a truss which supports the roof. 

Internal and external linings are made with sheet material, requiring no wet trades and therefore no dust and little noise onsite during the construction process. The use of sprayed insulation means that it is airtight. Underfloor heating, lighting, rooflight and extractor fan with humidistat can be controlled remotely from a smartphone, meaning that the space can be naturally or mechanically ventilated when uninhabited to ensure it remains dry when needed.

The frame took two days to erect, and the external linings and cladding another four to install, using just a team of two people. Internal linings, underfloor heating, flooring and furniture took a further four days’ work. The only specialist required for the scheme was the spray insulation contractor and an electrician. In total it took 20 days to build.

A room in the garden bed

Architect’s view

Architecturally, ‘A Room in the Garden’ is designed to exude the playfulness of a folly – one inspiration was the Pineapple House at Dunmore park in Scotland – with the patterned green cladding intended to partially and surreally camouflage the building in its natural surroundings.

It is designed for a family who are outgrowing their current flat and trying to resist the urge to move out to the suburbs. So this was a solution to provide more space, at least for the short to medium term, that also allows them the possibility to take the structure with them if they move – hence the need for easy disassembly and reconstruction elsewhere.

The interior is designed to adapt with the seasons: providing a sense of tactile warmth during the winter months, the large double doors enabling it to be opened to the garden in summer. The exposed timber structure which rises to the ceiling converging and framing the skylight, gives a central focal point and top light, ideal when seeking a place to read or for quiet contemplation.

In addition, the building features a number of innovations:

  • It uses digital fabrication to produce not just efficient structures or essays in digital form but also a work of architecture that is geometrically elaborate and spatially engaging;
  • It uses modern machine production techniques to make architecture that is both easy to assemble and accessible/affordable;
  • Digital fabrication is used to put architects back in the centre of the building process, less reliant on contractors and fabricators and using our skill set to directly produce the construction components;
  • It is a demonstration project for digital fabrication, a technology that is already upon us, in this case in the form of 2D CNC cutting. This flatbed technology is readily available and uses a sustainable, inexpensive and readily available material – namely plywood and wood panel projects (such as MDF);
  • Its assembly is a cleaner, healthier way of building that doesn’t risk health either during construction or in use;
  • It is simple enough for a self-builder to assemble – this building is a prototype for a product that can be sold as is but also in a number of different affordable variants and configurations;
  • It can be dismantled either to be adapted or reused elsewhere.

We passionately believe that architecture must be a synthesis of a conceptualised approach to aesthetics and the practical art of making. ’A Room in the Garden’ achieves that synthesis. In addition, we believe that architecture must continue to learn: in this project our client enthusiastically gave us the freedom to use this project as a research vehicle for a number of significant avenues of investigation. In each of these areas we have attempted to push the boundaries and innovate, creating something beautiful on a very modest budget.

Ben Allen, director, Studio Ben Allen

A room in the garden assembly

Project data 

Start on site November 2019
December 2019 (total time three weeks) 
Gross internal floor area 11.7m²
Gross (internal + external) floor area 15m²
Construction cost £28,500 (excl. VAT) including all internal furniture, fixtures and fittings
Construction cost per m² £2,435
Architect Studio Ben Allen
Client Jonnie and Rachel Allen
Structural engineer Format Engineers
Landscape design Daniel Bell Landskip
Installer Sullivan and Company
CNC cutting Hub Workshop
CDM coordinator Studio Ben Allen
Approved building inspector Not required as less than 15m²
CAD software used Rhino

All parts

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