TIMBER TREATMENT

Waikato Independent, Volume XLIV, Issue 108, 1 October 1947, Page 2

TIMBER TREATMENT

PROTECTION AGAINST DECAY f A factory for the pressure impregnation of timber agairst borer, termites, and wood-destroying fungi has been built at Riccarton, and is expected to start operations shortly. The factory has been established by a firm which has its headquarters in Auckland, and which has been using a British process for some months at a factory in Onehunga. The same process is being ut:.ed in Britain, South Africa, Europe, the United States, and Australia. The supply of durable heart timber is now short in New Zealand, and the company claims that its process will give sapwoods the durability of heart-woods. Both the Housing Department ! and the State Advances Corporation have approved the use of pressure-treated non-heart timber as an alternative to heart timber, and pinus treated by the process may be used for external framework without building paper. Actual treatment can be performed in a few hours if the moisture content is suitable for treatment. The timber is air-dried to a moisture content of about 30 per cent, and is then loaded on to bogies which are run into a pressure cylinder. With the cylinder full, a vacuum of 28 inches is drawn to suck air out of the wood cells, and the cylinder is then flooded with a toxic solution, and a hydraulic pressure of 200 lb a square inch is maintained until the calculated j amount of liquid is absorbed.