Danish and Canadian partners have developed a new laminated timber board that could ‘stretch’ the available volume of clear grade western red cedar and provide extended income potential for the forest industries.

Named ‘DoubleWood,’ the product comprises a cedar face bonded to a backing of Douglas fir. It is designed for interior and exterior cladding applications – and particularly for external ‘sidings.’

Western red cedar is highly regarded for exterior applications because of its natural stability, durability and attractive appearance. However, the availability of long, clear lengths is reducing – hastened by areas of old-growth forest being designated as national parks where felling is not allowed. Newer plantations give far less yield of clear timber than trees of 100 years or more.

This situation is not restricted to western red cedar, but with other species it is often possible to overcome the lack of natural long, clear lengths using technology such as finger-jointing. A specific problem with cedar cladding is that in many cases a natural, rather than painted, finish is required and finger-jointed material would not be visually acceptable.

The price of western red cedar has tended to increase steadily, without the usual fluctuations caused by changes in supply and demand or economic factors. While high prices often lead to falling demand as markets seek alternatives, the special characteristics of cedar mean that demand is increasing. And while strong prices benefit the Canadian forest industries in the short term, rising demand hastens the time when clear grade western red cedar simply won’t be available.

Rather than wait until then, the inventors of DoubleWood are seeking to address it.

The project started in 1999, when Peter Schroeder, chief executive officer of Danish company Schroeder & Co A/S International trading in forest products, joined forces with Dan Olsen, president of Danfor Export Ltd of Canada.

‘All my life I have been involved in the international forest products trade,’ said Peter Schroeder, ‘and western red cedar has been a special favourite of mine.’

Mr Schroeder was responsible for introducing solid western red cedar bevel and TGV sidings in Denmark 10 years ago. Since then demand has continued to grow: more than two million bd ft were sold in Denmark in 2000.

‘When I learned that supplies of clear western red cedar were expected to decline markedly,’ he said, ‘I decided something had to be done so that the timber would not suffer the same fate as other species which had once been commercially available but which are now non-existent.’

Lamination technology

The initial idea of Peter Schroeder and Dan Olsen – subsequently developed with technical and manufacturing assistance from Bob Gardner at Sawarne Lumber Co Ltd of British Columbia – was to create a laminated board with clear western red cedar for the ‘face’ and another species for the ‘back.’ This would reduce the volume of cedar used for any given level of demand and thereby postpone the time of serious shortage – or even better, help to balance supply and demand and extend availability until newer plantations matured to provide additional sources of clear grade cedar.

In theory the idea sounded simple. After all, lamination is hardly new technology, and the combination of two different materials, each with particular advantages but which complement each other, is a well-established scientific and natural principle.

However, as the partnership found out, it was far from simple in practice. Several months were spent in concentrated research to establish the most suitable timber for the ‘back’ and find the best manufacturing facilities. The fact that the final product was conceived, developed, protected by international patents and put into production within around one year is impressive.

Increasing demand

DoubleWood started selling in Denmark last year and, although initial uptake is slow (as expected), around a dozen 40ft containers have been sold and demand is increasing at a satisfactory rate.

DoubleWood comprises two, parallel laminated pieces of wood, with clear grade western red cedar bonded to a ‘backing’ of Douglas fir.

The first part of the process is to glue three pieces of wood to produce a ‘blank,’ with western red cedar in the middle and Douglas fir top and bottom. The wood is bonded under high pressure and heat, using phenolic WBP (weather and boil proof) glue – the same type of glue used in the manufacture of marine plywood.

After lamination the 3-ply blank is surfaced on all sides, profiled, and a groove is rebated along one edge. The blank is then split on a bandsaw, with the blade cutting at an angle to give two pieces of cladding each measuring 25mm in thickness on one edge and 12mm on the other.

The western red cedar that was at the centre of the 3-ply blank thus becomes the attractive sawn face of the finished cladding. When installed, the thinner edge slots into the rebated groove on the thicker edge so that only the clear grade cedar is visible.

‘Western red cedar is considered one of the best timbers for exterior siding,’ said Mr Schroeder. ‘In addition to its attractive appearance it is naturally resistant to insect attack and rot, and the structure of its fibres makes it very stable which greatly reduces the risk of splitting. It takes stain or paint well – and painted or stained western red cedar siding is known to last much longer than any other softwood siding.’

Although the initial driving force behind the development of DoubleWood was the desire to prolong the availability of clear grade cedar, the final product has proved to have a number of other benefits. For while cedar has many advantages it also has some disadvantages in use. As a lightweight and soft timber it is easy to damage and can split when nailed; the fact that solid cladding is cut thinly in order to eke out supplies adds to these problems and means that the cladding has to be supported at fairly close centres when installed.

The ‘backing’ timber in DoubleWood is construction grade Douglas fir supplied under Schroeder & Co’s ‘TREETOPS’ brand. The timber has greater strength and ‘stiffness’ compared with cedar and it holds fixings well. The combination of the two timbers therefore means that DoubleWood is more robust and easier to handle than solid cedar cladding – with minimum risk of the board splitting when nailed or screwed. Further, lamination results in a stable and strong board construction.

DoubleWood is manufactured in Canada and Schroeder & Co is the exclusive importer into Europe. The company has appointed wholesaler/distributor DDT – the largest in Denmark – to carry a stock of the product so that customers throughout Europe can place relatively small orders, perhaps as a sample. Larger volumes would be handled by Schroeder and delivered direct to customers.

With the investment in manufacturing, the opening price of DoubleWood was higher than for the equivalent cladding in solid cedar. However, even with the relatively limited volumes already sold in Denmark, the price has come down and is now on a par with solid.

Facing the future

Canadian companies that have seen the product have been impressed – but there is a feeling that many are still not facing the reality of cedar shortages and are putting off the need to seek a solution. As Mr Schroeder points out, if they act now they still have the chance to delay the inevitable, but if they wait too long it may be too late.

‘We are seeing growing demand in Europe, and as production volumes increase the price will fall to below the level of solid western red cedar clear grade cladding.

‘DoubleWood is fully developed and ready to fill a market need. During the development process it was interesting to see and realise the additional advantages that the product offers in terms of usability.

‘However, the environmental benefit is more important than anything else: DoubleWood can help save British Columbia’s diminishing resource of sought-after first growth western red cedar tree. The name DoubleWood not only describes the construction of the board – it also stands for the fact that the same volume of cedar can clad double the number of houses.’