Reconstituted wood panels are products made from wood particles bonded together to produce a flat sheet.
Particles range in size from fibres to large flakes. The main distinction between different products concerns the bonding between the particles. Bonding can be either through the addition of synthetic resin (particleboard, Medium Density Fibreboard) or through the refusion of naturally occurring lignin (wet process fibreboard).
There are four main groups of products manufactured in Australia:
- Particleboard, as defined in Australian/New Zealand Standard AS/NZS 1859.1:1997, is a panel product made from wood particles several millimetres in size. There are three types of particleboard. Standard particleboard is suitable for general-purpose interior use only where it will not be subjected to wetting or prolonged high humidity conditions. High moisture resistant (HMR) particleboard is suitable for areas of occasional wetting or high humidity. Particleboard flooring is manufactured specifically for use as structural flooring as defined in AS/NZS 1859.1:1997. Particleboard may be produced with fungicide, termiticide or fire retardant treatments. Such particleboard should comply with the appropriate Australian or Industry Standard and be designated "FT", "TT" or "RT" respectively;
- Medium Density Fibreboard (MDF), as defined in AS/NZS 1859.2:1997, is made from individual wood fibres compressed together with synthetic resin. It is denser and stronger than particleboard. There are two types of MDF. Standard MDF is manufactured for interior use only, such as furniture and general fit-out, while High Moisture Resistant (HMR) MDF is intended for use in areas of high humidity and occasional wetting such as bathrooms and laundries;
- Hardboard, as defined in AS/NZS 1859.4:1997, is produced by compressing wet individual wood fibres together. Refusion of natural lignins bonds the fibres together. Hardboard is often known by the trade name "masonite". The Standard classifies hardboard into four board types. Standard Hardboard Type GP is general-purpose board suitable for interior use. Type RD is reduced density board for specific interior use such as wall lining and floor underlay. Tempered hardboard is treated during manufacture to give a higher resistance to water absorption and a higher modulus of rupture than that of standard hardboard. It is intended for use in areas of high humidity or occasional wetting or applications where increased strength properties are required. Exterior hardboard is treated during manufacture to give a high resistance to weather. Hardboard is produced in Australia by the wet process, which gives sheets a screen back. This screen back may be planed off for certain applications and
- Softboard, a lightly compressed board composed of softwood fibres, water proofing agents and binders, complying with AS/NZS 1859.5:1997. Also known as fibre insulating board, it is very soft and is only used internally for heat and sound insulation.
Small quantities of wood panels under the designation "structural flakeboards" are imported into Australia. These products are termed Waferboard and Oriented Strand Board (OSB). They are engineered, mat-formed panel products made of strands, flakes or wafers sliced from small diameter logs and bonded with an exterior-type binder under heat and pressure. Strands are usually up to 150mm long and 25mm wide.
OSB panels consist of layered mats. Exterior or surface layers consist of strands aligned in the long panel direction; inner-layers consist of cross- or randomly-aligned strands. Waterproof and boil proof resin binders are combined with the strands to provide strength, rigidity and moisture resistance.
References: Timber Datafile P10 – Reconstituted Wood Panels of the NAFI Timber Manual
Structural Board Association Website: http://www.osbguide.com