Preservation Procedure

Performed on dry timber (less than 30% moisture content).
Once the autoclave is loaded with timber, it closes hermetically and vacuum is applied to pump out the air from the interstices on the wood pieces.

The autoclave is flooded with wood-preserving liquid and pressure is applied up to the required limits (between 8 and 18 kg per sq cm).

Upon saturation, when the preserving liquid ceases to penetrate, the excess is unloaded on to the auxiliary deposit and a final vacuum is applied to speed up runoff.


Wolman preservative is a water-soluble chromate copper arsenate stable oxides compound (CCA). It is the most used product worldwide for wood preservation. And Wolman is the number one selling brand in the U.S.A. and Latin America. This preservative is applied through autoclave, by a vacuum and high pressure system that forces it to penetrate timber. The CCA combines with wood sugars forming an insoluble precipitate which does not evaporate or leach.

It is absolutely clean and it may be painted, varnished, etc. And it does not attack either nails or metallic accessories.

Concentration of preservative applied varies according to the purposes of timber and the deterioration risk is determined by its use.


The amount of oxide, active component, present in wood (retention is measured in Kg x m3).

See Retention Regulations


Under ordinary use, exposed to weather conditions, MATRA guarantees a duration of over 25 years. This statement is based on the quality of the preservative used, the correct application method of the same and the vast experience of Wolman CCA manufacturers in the U.S.A. and in our country.