Green Woodworking Shelter | Invisible Studio

The project, by Invisible Studio and Pearce + is an innovative green woodworking shelter at Westonbirt Arboretum, complementing a pre-existing community shelter by Xylotek and Invisible Studio. Merging traditional green oak framing with advanced fabrication, it exemplified modern green timber construction. Traditional arboretum practices were blended with contemporary methods, creating a precedent for sustainable architectural design using unprocessed green timber in a modern structure.

The green woodworking shelter is a six-meter diameter structure with six raw tree limb legs and a triangular, green oak superstructure with stainless-steel flitch plates. Some 85 varied-angled holes were drilled and chiselled into the main frame, with each accommodating a 60x60mm green oak pole – each one set at a bespoke angle and individually lengthened accordingly to hold the domed roof across a series of slender columns. The poles were slotted and wedged into the holes, then hammered into the mainframe to secure them in place. Aluminium shingles, riveted over the pole ends, created a waterproof monocoque shell roof.

This project combined traditional, green timber construction with advanced digital fabrication, thereby streamlining the traditional, multi-layered shingle method for a double-curved form. Hemispherical washers were used to adapt to the movement inherent in the drying of green timber, and the structure itself acted as both the final structure and formwork for the curving roof. Over 10 months, the design was developed through iterative concept, prototyping and fabrication stages, allowing for responsive, on-site design evolution, even in the final build. This enabled the waste reduction and the pioneering of a flexible cladding connection for drying green timber.

Structural engineer Lean Structures Ltd

Photography: David Butler

Website: https://www.dnbutler.com/