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New Zealand radiata pine is an excellent raw material for the LVL process. LVL is used mainly in beams, I-joist flanges, scaffold planks, truss stock and for joinery work. It is over 40% stiffer and stronger than stress-rated timber and 15-20% stiffer and stronger than glue-laminated timber. These properties make LVL preferable for structural purposes over other lumber products. With LVL the same structural integrity can be achieved using less material, and less weight to the structure.
Laminating improves the strength of wood by dispersing the weakness from defects (e.g. a knot) over a greater area. In effect, it increases the strength of the weakest part of a length of wood.
The production process for LVL is essentially the same as that of construction grade plywood, with three main differences: the sheets are much thicker than plywood (up to 75 mm); each veneer sheet is laid with the wood grain oriented in the same direction; and continuous lengths of up to 25 m can be produced. Continuous presses are used to manufacture LVL and the material is cut to the required dimension.
Laminated veneer lumber (LVL) production in New Zealand has increased dramatically over the past few years. Combined plywood and LVL production in 2004 was almost 350,000 m3. |