About Composite Products
Laminated Timber (incl. LVL)
Medium Density Fibreboard (MDF) incl. hemp board
Plywood and Outgassing
Natural vs Synthetic Timber
The shortage of high-quality timbers has led to a rapid increase in the cost of larger formats of timbers. Globally, large (and old) timber trees are becoming evermore scarce to the point of being endangered - particularly some of the favoured rainforest species. In order to avoid logging these rare tree types to extinction, the following glued-wood products could be considered.
There are various composite and reconstituted timber boards available - such as plywoods and hardboards. The conversion-rate from tree to useful material can be 80 to 90 percent for these composite products, compared with only about 40 percent for solid timber. The look of solid timber can be attained through the use of plantation-timber veneers.
In line with the trend towards more 'natural' wood products and in response to consumer demand, European chipboard makers have for some time been attempting to produce a Bio-board. Manufacturers are aiming to deliver a board which belies chipboard's traditional "groggy" image, consistent with high formaldehyde glue values 1.
There are three basic conditions which European (and hopefully Australian) manufacturers hope to fulfil in order to improve their products' quality and environmental-friendliness:
This would produce a product with a more natural colour, smell and appearance.
Researchers and product developers are very quiet about launch dates for Bioboards, but development is definitely under way at several locations 2. Also, most hemp based building boards qualify as bioboards, with the added advantage of being wood-free.
About Composite Products
Composite timber products have many advantages over ordinary timbers such as Oregon. They can utilise smaller dimensions of timber as the raw material, but can be manufactured to create large dimension composite beams and sheets, etc. Less timber overall is required to make products which are lighter and stronger than timber. Lower quantities and smaller sizes of timber means less pressure on native forest timber. Prices of imported timbers will continue to rise which will continue to make composites a more attractive proposition for builders and designers.
Composites products are manufactured using either epoxy or formaldehyde glue 3. Both of these can emit trace quantities of chemical vapours and gases in our homes and buildings. If they are to be used in living areas, then they should be sealed with a quality paint. If you can't find recycled or plantation timber to suit your needs, specify composite products made with phenol formaldehyde (or non-formaldehyde) glue, which gives off only minimal amounts of gas. Always follow the manufacturers safety instructions when working with glued-wood products or treated timber.
There may be a few responsible manufacturers who are using non-toxic glues, no formaldehyde and 100% sustainably-harvested wood - we hope so. The voice of the consumer must speak out and demand that non-toxic, lower-impact alternatives be made more readily available.
Remember if you do require a glued wood product, to ask for one made from either plantation-grown timber, plantation thinnings, or sawmill waste - these are readily obtained on the Australian market.
This product is created by a process whereby small pieces of timber and off-cuts, which might otherwise have been discarded, are joined together to form longer members. Finger-jointed floorboards are a better alternative to long, single-length floorboards because long boards usually have come from very large, very old, majestic trees - and there are too few of these left!
Laminating has long been used to make large pieces of timber even larger; for example, to cover large roof spans. Our recent need to maximize our economies of timber-use, combined with advances in glue technology, has led to the development of some innovative methods for combining small pieces into useful, workable sizes. Laminated Veneer Lumber 4 (LVL) is made from veneers of Radiata Pine or Slash Pine, glued under pressure (usually with phenol formaldehyde, also known as Resorcinol). Advantages of LVL includes its structural reliability, its strength and stability and ease of use.
LVL composite beams:
Glulam is made by laminating thick pieces of seasoned, dressed timber in order to make larger structural members, bench tops, stair treads, etc. This is best for interior use, where preservatives are not needed. Timber retailers may have to order-in supplies according to the buyer's request.
Because of new gluing and production processes, glue-laminated wood has almost the tensile strength of solid timber.
Valwood is a material developed in Western Australia and utilizes regrowth Jarrah thinnings from reclaimed farmland. The wood is used in such a way as to eliminate inherent stresses in young wood: small pieces of regrowth hardwood 10mm thick and 80mm wide are glue-laminated together. This enables quality sawn timber to be obtained from younger trees.
Medium Density Fibreboard (MDF)
MDF comes midway between Hardboards (such as Masonite) and Softboard, which is often used for insulation. MDF, which is more like a typical timber, is available as mouldings as well as sheets.
MDF is a glued timber product, usually manufactured from plantation thinnings. According to the Timber Trader Journal back in November 1992, MDF products were even then gradually replacing many hardwood components in the furniture industry. Indeed, Timber Trader reported that MDF production was then increasing worldwide as consumers took up new opportunities to make the most efficient use of wood.
MDF can be used as a substitute for rainforest timbers in a number of ways. For example, it is increasingly being used for doors and door-surrounds, decorative mouldings, rails, skirtings and cornices.
MDF products can also be given a solid wood appearance by wrapping the MDF in a wood veneer. This saves on the use of solid timber and offers an excellent means of avoiding the use of tropical plywood.
Most MDF is not moisture-resistant and can only be used in dry, interior locations. However, some types are now specially produced for use in moist interior situations, such as bathrooms, laundries and kitchens - check with your timber merchant. All known types of MDF are pressure-bonded with Urea Formaldehyde resins, making them all potentially dangerous.
NB: There is apparently a hemp-based, formaldehyde-free MDF board on the market in Australia, but no details yet. A product called Urban Waste MDF, made from demolition timber and old pallets is being sold in the U.S. and Canada. Please let the Guide know if you hear of non-toxic glues or glued timbers on the market.
Listed below are common brand names for MDF:
This is similar to fibreboards, except that the constituent wood is present as small particles and flakes, not reduced to fibre. It can be used raw, when appearance is unimportant. Veneered with hardwood, it is the basis of much wooden furniture.
A manufactured board derived from woodchips reduced to fibres, reconstituted to give flat, smooth-faced, evenly coloured building board in several grades and thicknesses. Being easily workable, it has many uses.
Plywood is made from a number of glued layers of wood veneer. The major uses of plywood are wall-panelling, door-skins and concrete formwork. It has also made a name for itself as a furniture building material of enormous strength and which can be moulded to produce interesting yet functional designs.
It has been estimated that in 1991-92, Australia imported $41 million worth of plywood, 67 percent of which was manufactured from tropical rainforest timber. Most of this rainforest plywood was manufactured in Indonesia.
The Good Wood Guide recommends the use of Australian-made plywood, manufactured from plantation-grown trees. Plywood suitable for Class 3, 4 and 5 formwork can be manufactured from 100 percent plantation Radiata Pine. Plywood suitable for Class 2 formwork (where a high-quality, architectural finish is required) can be manufactured from Radiata Pine with a plantation Hoop Pine outer veneer.
The EcoDesign Foundation 5 cautions that glues used in plywood manufacture can have emissions which are potential health hazards. They call this 'outgassing'. Interior-grade plywoods contain urea formaldehyde glues which outgas at room temperature, while the phenol formaldehyde glues used in exterior grade plywood do not. The Foundation says that many architects, therefore, specify exterior grades of ply for interior use.
The Plywood Association of Australia 6 has published an info sheet called "Formaldehyde Emission from Plywood Products". The Association's report tends to play down any potential hazards - as opposed to the Ecodesign Foundation, which strongly advises caution, and consideration of alternatives.
NB: Plywood is not the only source of formaldehyde emissions in modern buildings.
Formaldehyde is also emitted from:
It may be that the cumulative effects of the various sources of this gas can cause 'sick building syndrome' 7 which means sick people!
It must be said that chipboards, fibreboards and composite beams, etc, possess nothing like the beauty and natural feel of solid timber. Even if they are veneered, it's not quite the same, somehow. It seems as if the twentieth century's excesses have forced us all to embrace less than ideal options in order for us to work our way back to natural and cultural equity.
Yet, they (glued-wood particles and fibres, and finger-jointed composites) have made a niche for themselves in the marketplace, as much for their structural efficiencies as for their ability to lessen the load on native forests. There are many afficionados of plywood, for example, who have great respect for its strength, stability, and versatility in design, when compared with timber.
As a General Rule 8. . .
1. Whenever possible, choose recycled timber or a non-timber structural medium for your job.
2. If this is not a viable option, then look at using plantation timber 9.
3. Only then consider composite timber, particle board, fibreboard, etc. (Note that the bulk of materials for composite wood products come from plantations - the glues used are mostly petroleum byproducts. Question your supplier regarding any old growth forest timber component in their products).
1. See Plywood and Off-gassing, above. There is one U.S. company which manufactures a formaldehyd-free particle board called Resincore.
2. See also Hemp Construction Products
3. See also Glue
4. See Composite Beams and Trusses in the Directory.
5. See Ethical Advisory Groups, in the Directory
6. See Timber Industry Promotion Groups in the Alternative Directory.
7. See Healthy Home & Healthy Office, by Reinhard Kanuka Fuchs, in Books, Chemicals in the Alternative Directory.
8. See also Timber Recommendations for Australian Users.
9. Of course, the order of preference here might change if the structural superiority of composite materials is a high priority - such as with large roof or floor trusses.