Losp Treated Timber

Wood - the renewable building material

Growing trees are an essential element in the carbon cycle; absorbing and storing carbon. By prolonging the durability and therefore the life of wood we can increase our carbon storage capacity.

We can increase the durability of wood and timber products by a preservative treatment known as LOSP.

LOSP treated timber products such as framing, fascia, weatherboards, sills and window and door joinery will last much longer than it takes for replacement trees to grow.

LOSP treatment process

LOSP is a white spirits based wood preservative.

LOSP treatment of timber involves the impregnation of preservative into wood using controlled vacuum processes in such a manner as to ensure that preservative is not spilled nor personnel placed at risk.Timber can be LOSP treated to the following hazard classes;

  • H1.1 and H1.2 for timber framing
  • H2 (Australia only) for timber framing
  • H3.1 for use outdoors out of ground contact where there is no possibility of water entrapment such as fascia and weatherboards.
  • H3.2 (CuN only, refer to NZS 3640 for retention specification) for use outdoors out of ground contact but with a risk of water entrapment such as joists and decking.

Safety and the environment

Because your safety and the safety of your family and friends is important to the producers of LOSP treated wood we want you to have all the facts.

Our recommendations are intended to reflect common sense and good hygiene practices as apply when building with any wood product.

  • Avoid working with LOSP treated timber in a confined space.
  • When power-sawing/machining any timber wear goggles to protect your eyes from flying particles and a mask to avoid dust inhalation.
  • If sawdust accumulates on clothes, launder before re-use. Wash work clothes separately from other household clothing.
  • After working with LOSP treated timber products wash your hands before eating, drinking, smoking or otherwise placing your hands near your mouth.
  • LOSP treated offcuts and sawdust should not be burnt for firewood or any other reason nor used in barbecues. Disposal to a designated landfill is appropriate.

Use of LOSP Treated Timber

  • LOSP preservative treatment will not swell or otherwise affect timber dimensions. It is therefore ideal for treating timber in its final shape and form thus reducing timber waste and preservative use.
  • LOSP treated timber is used for structural purposes such as wall framing and roof trusses.
  • High value timber building components such as fascia, weatherboards, door and window joinery, panelling and sills are LOSP treated in their final shape and form.
  • Correct use of all treated timber in building is specified in the New Zealand Building Code and in NZS 3602 : The Use of Timber & Wood Based Products.

Non-solid wood products such as LVL, glued laminated timber and plywood are frequently LOSP treated. These products are treated in accordance with AS/NZS 1604 Parts 2 to 5.

Care in use

  • LOSP treated timber should not be used in the manufacture of beehives.
  • LOSP treated wood should not be used where it may come into contact with public drinking water.
  • LOSP treated wood should not be used in the manufacture of toys for young children or for use as cutting boards, counter tops, food bins or similar applications involving direct contact with food.

WOODmark® branded timber - your assurance of quality treatment

Reputable LOSP treaters are licensed to use the WOODmark® brand. The WOODmark® brand signifies that timber has been treated to the requirements of the New Zealand Standard NZS3640:2003 and that the treater follows the quality assurance procedures laid down in the New Zealand Timber Preservation Council's Timber Preservation Quality Manual.

Make sure you buy and use only WOODmark® treated timber and wood products.