Since Roman times the sweet chestnut – prevalent in southern England – has served a small but useful purpose. Mainly coppice grown, it has been used primarily for fencing and hop poles, with some going to the joinery sector – often in southern Europe.

But while these markets have declined, sweet chestnut is undergoing a renaissance thanks to the vision of Nigel Braden and Edward Stenhouse of Inwood Developments Ltd in East Sussex.

To put it simply – they take long pieces of sweet chestnut, cut them into small pieces and glue laminate and finger-joint them to make a stable structural timber.

An architect by profession, Mr Braden set up a hardwood sawmilling plant at the Woodland Centre at Whitesmith, East Sussex after the great storm of 1987 in partnership with Tony Penrose.

However, that business came to an end in the mid-90s and Inwood Developments was born. Mr Braden, who was involved for seven years in getting the British standard for sweet chestnut, explained: “It was set up with very strong environmental criteria specifically to develop a system for gluing and finger-jointing small diameter British hardwoods.

“We developed the technology for the Woodland Enterprise Centre at Flimwell and mainly use 30 to 40-year growth chestnut, all coppice grown mostly in the south of England, and all about 150-250mm diameter. We produce sawing blanks from 2m lengths then grade it and cross-cut it.”

Highly sustainable

Mr Braden said there are 18,000ha of sweet chestnut in southern England. “We take a small proportion of the annual increment growth and it is highly sustainable. With coppicing, the tree regrows from the same rootstock, so we are not killing the tree but maintaining a historic silvicultural system.”

“Chestnut over a certain size develops ring shake which is a major problem for the timber. But you can take smaller logs and really upgrade it into a number of different forms.”

The logs are sawn at a commercial sawmill before going into stock to air dry.

At the Woodland Centre the logs are processed through a modern cross-cutting system. They are then visually graded and the knots are taken out to the BS standard for grading hardwoods for structural use. An Omga machine cuts the timber into defect-free pieces ranging from 250mm up to 1.5mm and 6m lengths are finger-jointed and glued on a Grecon machine in one operation. The company is looking at investing £250,000 in a fully automated plant.

Mr Braden said: “The gluing and finger-jointing came about around seven years ago. We were the first manufacturers to use green gluing technology – you can use high moisture content timber which reacts with the glue to give a very strong joint. We did the R&D to find the right glue which is a polyurethane system.”

A contact layer of glue is put between each layer of timber to make up the beam which is then pressed from the side and the top in a Stromab vertical press. After two hours the beam is ready to be sanded and sealed.

Mr Braden said it is the only structurally rated process of its kind in the country and, as there are no knots or defects, the resulting beams have more weight-bearing capacity than a solid oak beam.

Building components

Now Inwood Developments has begun to prefabricate building components in its framing yard – the latest being the components for a building at Shorne Wood Country Park near Gravesend.

“We are creating 16 frames for the building which is 50m long and 15m wide, like a curved snake. It was designed by the Lee Evans Partnership in Canterbury and we had input about what we could make so the design could be modified to any limitations.”

Inwood supplied finger-jointed lengths of laminated oak for the debating chamber in the Scottish Parliament and larch for the Saville Gardens Gridshell in Windsor Great Park – but Mr Braden said: “Sweet chestnut is what we are passionate about; it is a local resource and a good timber that needs to be used in a creative way.”

Mr Braden believes there is a good future for British timber if it is marketed correctly. “We need to focus on the home-grown and sustainability issues which will get people back to appreciating a local product.”