Stihl Treetop Walkway

Winner: Commercial & Leisure Award

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The grade I-listed Westonbirt Arboretum is home to one of the finest tree collections in the world. The Stihl Treetop Walkway provides stunning new views over this landscape, enhancing the appreciation of the estate’s natural heritage. At almost 300m in length, it is also the longest structure of its kind in the UK.

Using the land’s natural topography, the walkway crosses a valley, giving easy ground-level access without the need for stairs or lifts. At four points along the route it gently widens from 1.9 to 3.7m, providing spaces for pausing, reflection, and interpretation of the surrounding woodland.

This is a hybrid timber and steel structure. Great efforts went into ensuring that when touching the handrail on either side, walking on the decking, or viewing the ­visible columns seen under the walkway, the visitor’s experience would be of timber. Larch was chosen as the main material, for its durability and attractive colour, with Scottish larch used for the decking and handrail and, for the columns, Siberian larch which has a tighter grain and higher strength-to-weight ratio.

 

 

  • Although this is a hybrid timber and steel structure, timber dominates the visitor’s experience...
    Although this is a hybrid timber and steel structure, timber dominates the visitor’s experience...
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Glenn Howells partnered with Ventis & Brasker Masten, a Dutch maker of ships’ masts, to deliver strong, light and elegant timber columns. The mastmaker was able to achieve in timber what could otherwise only have been done in steel. It created specially tapered columns, notching and reinforcing the ends with steel plates to ensure they could manage the loading and height. The legs were then oiled to slow the drying of the timber and to minimise cracking. Micro­nised copper was used to treat the decking and handrail, providing a 30 year warranty.

The judges said: ‘Not only is this a striking composite structure of wood and steel in which wood is doing all the exciting bits; it is also an educational response in itself. It has the ability to inspire all generations to learn more about wood.’


Location Westonbirt, The National Arboretum, Gloucestershire

Architect Glenn Howells Architects

Client/owner Forestry Commission

Structural engineer Buro Happold

Main contractor/builder Speller Metcalfe

Joinery company S H Structures

Wood suppliers CTS Bridges, Ventis & Brasker Masten, Russwood, Heseltine Design

Wood species Scottish and Siberian larch


 

Highly commended 

Mottisfont Welcome Centre

 

Location Mottisfont, Hampshire

Architect Burd Haward Architects 

Client/owner The National Trust

Timber frame consultant Constructional Timber

Structural engineer Thomas Consulting 

Main contractor/builder Beard Swindon

Timber frame contractor Sylva Group 

Wood supplier Vincent Timber

Timber decking supplier Hoppings Softwood Products 

Timber flooring supplier Orlestone Oak 

Wood species European spruce, European larch, Canadian western red cedar, thermally modified Scandinavian redwood, European oak, plywood & OSB sheathing


 
Shortlisted
Shortlisted: Alconbury  Weald Club
Shortlisted: Alconbury Weald Club Credit: Location Alconbury Weald, Huntingdon Architect Allford Hall Monaghan Morris
Shortlisted: Gloucester Services
Shortlisted: Gloucester Services Credit: Location Brookthorpe, Gloucestershire Architect Glenn Howells Architects
Shortlisted: Sky Health & Fitness Centre
Shortlisted: Sky Health & Fitness Centre Credit: Location Osterley, London Architect dRMM