ENGINEERED WOOD PRODUCTS
When we think of using wood, we often first think of solid wood. The traditional post and beam method of construction comes to mind. These days, however, if we opt for solid wood, we may find we are selecting a very expensive building product. Indeed, if our solid wood comes from an old growth forest or a rainforest. our choice may be unfavourable on environmental grounds as well.
Recent developments in wood technology are bringing alternative wood products onto the market that manipulate the basic properties of wood to our advantage. 'Engineered Wood" is a generic term used to describe this range of new products. The common characteristic is that they all maximise the utility of wood's basic elements to minimise wood waste. in other words, engineered wood products enable us to do more with less.
Engineered wood products are also important from an environmental point of view because they allow us to use our smaller plantation trees for a wide range of structural applications. This is helping us with the necessary transition from native forest logging to plantation based forestry. There is also a world wide trend to investigate using alternative fibres such as hemp for use in engineered wood products, which in turn could make plantation based forestry a thing of the past.
The products we discuss in the following sections all require extra processing and the use of glues and resins, therefore, they should only be considered when the application we have in mind uses the engineered characteristics of the product appropriately. Contact the recommended Good Wood Supplier for product information sheets, span tables and safety information
Finger joining is a process whereby small pieces of timber and off cuts, which might otherwise have been discarded and wasted, are joined together to form longer pieces. The joints are made by machining wedge shaped fingers into the end of the small pieces, and then mating the fingers with another machined piece (like the way our fingers intermesh when we join hands). When glued, the wedge shaped ends lock to form a very strong bond. Finger joining has been used successfully for a number of years to produce long lengths of high grade timber from mixed low grade lengths.
joined lengths can then be used as they are, for example in picture
frames where a clear finish is important, or they can further processed
by lamination. In lamination, the finger joined pieces are glued one
upon the other to form structural beams, posts, joists, and a wide range
of other timber products. The lamination of finger joined pieces randomises
defects and creates a stronger end product. Thus, not only do we utilise
what was once waste, we use less timber overall to meet our specification.
The lamination and finger joining process is also very efficient at the sawmill. Timber specifications can be customised and lengths of timber are not cut unnecessarily. Another advantage is that the process enables the manufacturer to make best use of our clear and knotty grade softwoods. Valuable lengths of high grade appearance timber are used only where they are most appreciated.
Finger joined and laminated timber can be used for:
beams joists pickets
floorboards lining boards framing timbersThere is no longer any real need to specify old growth or rainforest hardwoods, particularly in construction applications. Glued products engineered from privately owned softwood forests are now readily available. With thoughtful use, not only do we avoid logging forests of high conservation value, by using plantation grown timber we use less timber overall.
Beams are our primary load bearing members and one of the most important wood products for building. The recent innovations of finger joining and lamination we have discussed above are giving us new options to design and build with engineered beams. These new products have a number of benefits relevant to the context of this book. For example, engineered beams have a superior strength to weight ratio and they are available in long lengths (up to 27.6 metres for laminated beams). These characteristics allow us the opportunity to specify a plantation grown beam instead of the traditional old growth or rainforest solid timber beam. Some of the engineered beams available are:
>Stockspan II laminated beams are produced in Mount Gambier and utilise lower grade Radiata Pine core materials with specially graded top and bottom layers to give strength. The beams are produced with waterproof resorcinol glues to an appearance architectural grade that have a pleasing appearance when varnished. Stocked in 18.3 metre lengths, this product can be used for a side range of domestic and commercial building applications.
Supa Lam and Bilda Lam are laminated beams manufactured from Radiata Pine sourced from plantations in Western Victoria and South Australia. Available in lengths up to 18 metres, the beams are suited to a wide range of applications in commercial and domestic structures. The glues used are Resorcinol for external grades and PVA for internal grades.
Laminated Veneer Lumber ("LVL" or "Hyspan") are beams made from veneers of plantation Radiata Pine. Sheets of veneered wood are glued together with the veneer grain running in the same direction. The glued layers form a billet which can then be sawed to form the desired beam. One of the major advantages here is that the process randomises any of the natural weaknesses of the wood to produce a beam with a highly uniform strength.
Laminated Veneer Lumber is used to make I beams, trusses, hanging beams, strutting beams, under purlins, ridge beams, floor joists, bearers, lintels, rafters, truss member and wall girts. LVL also has a range of possible applications in the furniture, window and door industry. The glue used is usually phenol formaldehyde or Resorcinol.
Valwood is a material developed in Western Australia and utilises plantation grown Blue Gum or regrowth native tree species. The wood is used in such a way as to eliminate the stresses inherent in young wood. Small sawn pieces of immature hardwood 10mm thick and 80mm wide are glue laminated together. This enables quality sawn timber to be obtained from younger trees.
Hynebeam 17C is an engineered rectangular beam made from slash pine. Three grades exist and maximum length is 18.4 metres, and the cross sectional dimensions range from 130 by 38 mm to 800 by 115 mm. Hynebeam 18C is made from native timbers and is best avoided. Another product Edgebeam is made from slash pine and comes in lengths of up to 12 metres.
A truss is a framework of timber constructed to form a firm support for a load such as a roof. Prefabricated Radiata Pine roof trusses are now a common product on the Australian market. This is desirable as the use of plantation grown timbers for trusses is replacing the native forest timbers traditionally used, particularly the green scantling grades. This will take some of the pressure off our native forests. Also desirable is the trend to using the engineered plantation timber products in trusses. This helps us to make the most efficient use our plantation timber resource.
The timber trusses we use in Australia are manufactured under a number patented joining systems. One of the most common of these joining systems utilises metal "nail plates' with punched teeth. Nail plates have been used in the manufacture of trusses for at least twenty years and nail plate trusses typically span six to eighteen metres.
Wood based panels can be divided into four main product types: plywood, medium density fibreboard, hardboard and particleboard. During 1993 94, Australians consumed around 1.3 million cubic metres of logs in the form of wood based panels approximately 7 per cent of all the logs produced (ABARE 1995). another way, we use about a million trees in this sector of the forest products market each year.
Plywood is made from high quality sawlogs using a number of glued layers of wood veneer. The major uses of plywood are wall panelling, door skins, concrete formwork, flooring, bracing, fabricated beams and cladding.
Rainforest plywood veneers presently constitute around 12 to 18 per cent of our total Australian consumption by volume. In 1997 98, Australia imported $61 million worth of plywood, with over 50 per cent of which was manufactured from tropical rainforest timber with Indonesia being the largest supplier.
Our heavy reliance on rainforest plywood imports should be reason for concern on at least three grounds. First, it shows that Australia does not produce enough high quality, locally grown Radiata Pine, Hoop Pine or Slash Pine to meet even our current domestic demand, let alone supply a growing export market for sustainably managed timber products. Second, it demonstrates our shortsightedness: we are meeting nearly three quarters of our domestic shortfall from an unsustainably logged source. Third, our continued reliance on rainforest plywoods shows that we are not realising an opportunity to develop a value adding segment of our domestic plantation industry.
Friends of the Earth recommends the use of Australian plywoods manufactured from plantation grown, trees in preference to imported rainforest plywoods manufactured from unsustainably logged trees. Australian substitutes are readily available at competitive prices for structural grades. Substitutes for appearance grades are also readily available, although staining may be required to render an equivalent finish. We need to make our preference for sustainably managed forest products known to the market so it can respond to our wishes.
Medium Density Fibreboard (MDF) is a glued timber product usually manufactured from plantation thinnings or lower grade pulplogs. The product machines well and has a smooth surface, characteristics that make MDF a versatile substitute for many of the solid hardwood components traditionally used in our furniture and construction. For example, MDF is increasingly being used for doors and door surrounds, decorative mouldings, rails, skirtings and cornices. Windows made with a new high performance MDF are now being manufactured in Germany. All these products have traditionally been manufactured from tropical rainforest species.MDF products can be given a solid wood appearance by wrapping the MDF in a wood veneer
BEWARE: While we recommend coating MDF with a veneer, some veneered MDF products labelled "Australian Made", "Environmentally Responsible" or "Specialty Veneers" are in fact rainforest species (both Australian and Imported). Be sure to ask for a veneer made from a sustainably managed good wood, such as Poplar, Hoop Pine or Radiata Pine.
All MDF is pressure bonded with urea formaldehyde resins. Most MDF is not moisture resistant and can only be used in dry interior locations. Some types of MDF are now specially produced for use in moist interior situations, such as bathrooms, laundries and kitchens (e.g., CSR's Fibron). Asbestos free fibre cement is a suitable alternative to MDF in these situations.
MDF is one of the few value added forest products Australia manages to produce enough of to export. 90% of Australia's imported MDF however (worth $31 million) comes from New Zealand where the fibre source is plantation grown. Australia also imports about $3 million worth of MDF from Malaysia. However, most of the MDF we use is manufactured in Australia from the residues obtained from milling our local >softwood plantations. The strong demand for MDF, like most forest products, is now beginning to cause some in the industry to turn a wistful eye toward our native forests. This is surely another sign that we should be planting more native hardwood trees on degraded land.
Listed below are common brand names for MDF products and a short account of the fibre source.
Craftwood is manufactured by Laminex Industries. Its plant in Gympie, Queensland, uses Slash Pine thinnings and its plant in Wagga, New South Wales, uses Radiata Pine thinnings. (Beware of using Craftwood bonded to the Laminex Natural Timber Veneer range as some of these "Australian Made" veneers are in fact imported rainforest species.)
Customwood is manufactured by Canterbury Timber Products in Rangiora, New Zealand. Eighty per cent of the chip in this material is Radiata Pine. The balance is made up of a mixture which includes Douglas Fir, Corsican Pine, Ponderosa Pine, Willow and Poplar.
CSR MDF (Fibron) is manufactured by CSR Wood Panels at its plant in Oberon, New South Wales. It is made from Radiata Pine thinnings.
GoldenEdge is made by Nelson Pine Industries in Richmond, New Zealand. It is manufactured solely from plantation grown Radiata Pine thinnings.
Lakepine is manufactured by Fletcher Wood Panels in New Zealand. It is manufactured solely from plantation grown Radiata Pine thinnings and sawdust.
Particleboard is similar to fibreboards except that the constituent wood is present as small chips, not reduced down to fibre. The material also typically contains urea formaldehyde and paraffin wax, which are combined with the wood fibre _and bound together under heat and pressure. Particleboard can be used raw when appearance is unimportant. Veneered with hardwood, it is the basis of much wooden furniture. Most particleboard, however, is used in construction. Australia's main source of imported particleboard is from plantation sources in New Zealand (almost 97%) although we did import $163,000 of particleboard from Malaysia in 1997-98.
Superfine and Bisonboard are particle boards manufactured by Fletcher Wood Panels in New Zealand. They are manufactured from plantation grown chips from thinnings or residue.
Pyneboard, Texpan and Fineline are manufactured by CSR Wood Panels in two locations: Mount Gambier and Tumut. The source fibre at both locations is Radiata Pine.
Hardboard is a denser form of fibreboard. In 1997 98, Australia imported about $5.6 million of particleboard, with Brazil being our biggest supplier. In locally produced hardboard, the increased density is achieved through using hardwood sourced from native forest residues rather than softwood plantations (hardboard is typically about 95 per cent native forest hardwood). In Victoria, most hardboard was manufactured by CSR Wood Panels at Bacchus Marsh sourced from hardwood waste from the Wombat Forest. The Bacchus Marsh mill closed down in 1996. The products made at Bacchus Marsh were called Masonite (braceboard and underlay) or Weathertex (wall shingles and exterior wall cladding). Masonite is still made by CSR in Ipswich Queensland from native hardwoods. Weathertex is made from Australian hardwood at Raymond Terrace in New South Wales and is not recommended.
Fibre cement might also be classed as a wood based panel product and may be worth considering for a number of building applications. For example, fibre cement can be used for external wall cladding, caves and ceiling lining, external decking, structural bracing, roofing, internal wall linings, wet area flooring, floor underlay, lattice screening and fencing.
The fibre component of fibre cement products used to be asbestos. These days, locally manufactured fibre cement products use wood as the fibre reinforcement. Some imported fibre cement may still use asbestos fibre and should be avoided. Asbestos is known to be hazardous, particularly if inhaled as dust.
The largest manufacturer of asbestos free fibre cement products in Australia is James Hardie & Co Pty Ltd. This company uses unbleached plantation grown Radiata Pine from New Zealand as fibre in its fibre cement range of building products.
A product called Ecopanel has recently been developed made from 100% agricultural waste (wheat straw). It is binded together by a fomaldehyde free resin making it very environmentally friendly. Ecopanel can be used in any application where chipboard would normally be used. Ecopanel comes in sheets of 2400 by 1200 mm and comes in a range of thicknesses from 4, 6, 9, 12, 16 and 18 millimetres. Ecopanel can be used for flooring.
Much of the following information comes from a final year research project at RMIT by Andrew Gemmell.
Industrial hemp has a myriad of uses. It has well known uses such as for paper and fabric as well as obscure uses such as in paint and concrete. Roulac, 1996, p 11, states: 'Anything that can be made from a hydrocarbon can be made from a carbohydrate*. Roulac, 1996, p24 suggests 25,000 products can be made from industrial hemp. Canadian research has shown that in a 20 year period just 1 acre of this crop could produce as much pulp and paper as 4.1 acres of trees, thereby preserving native forest habitats for the species which inhabit them. Hemp paper can be recycled 7 8 times while wood pulp paper can usually be recycled 3 times.
The manufacture of particleboards in the early days was similar to the wet process used to manufacture paper. Hemp has been used in the manufacture of particleboards in eastern Europe as well as in Holland and France and in the state of Washington, USA, sample particleboard panels have also been manufactured from hemp. Robinson, 1996, p43 states: 'The high tensile strength of hemp fibre makes it suitable as a low density reinforcing material in applications such as fibreglass"..
The leaves of the Cannabis plant can be used as nutrients for the soil and the seed has been used for centuries as food. The extraordinary number if uses of Cannabis is complemented by the environmental benefits of its growth. The plant produces a M to 12" root in only 30 days (Herer, 1993, p48) thus making it suitable for binding of soil damaged by erosion. The current legal status of Cannabis makes the creation of a hemp industry difficult although change in the UK (in 1993), USA (state of Nebraska legalised industrial hemp in 1998), Canada (1996 the Canadian House of Commons approved Bill C8 removing mature hemp stalks from a list of controlled substances in Canada) and Australia is occurring. In Victoria the laws have changed to allow strictly regulated commercial and research crops although these laws remain as amendments to the Drugs, Poisons and Controlled Substances Act, 1966 and Regulations. In the Cannabis sativa trials undertaken in south eastern Australia, the Victorian authorities set the THC limit at 0.35% and the NSW authorities set the THC limit at 0.3%.
Based on results by Lolicato, Bluett and Blackstock, 1996, p4 yields of 10 tonnes per hectare can fairly easily be achieved now using European seed in Victorian conditions grown by farmers with minimal hemp growing experience. Furthermore existing particleboard factories could easily handle the hurd and hemp stems to be made into particleboard. Experiments based on hemp procured from five sites in Echuca, Warragul, Ballarat, Benella and Moulameia (NSW) show that hemp can successfully be used as a substitute for plantation wood in particleboards. It can also be concluded that hemp could also be successfully used as a substitute for wood in medium density fibreboards, although a binding agent such as formaldehyde would have to be used. What is needed is the political will to support the hemp alternative.
What has recently happened in Canada could provide Australia with a model to work from. In late 1996 government grants were successfully awarded to hemp growing groups for 1997 98 for research, educational and agricultural purposes. A comprehensive report was published summarizing the results of those learning experiences. By 1999 more and more farmers are obtaining hemp licences and seeds are in high demand. in 1997 a Kent county firm called Kenex Ltd began building Canada's first hemp fibre processing plant. By 1998 the processor was up and running. Now that raw hemp can be processed domestically and there is likely soon to be a surge in Canadian made hemp products, such as food, cosmetics, bags, clothing, paper and building materials.
The Good Wood and Paper Guide FRIENDS OF THE EARTH 1999