CCA is one of the world's most popular wood preservatives, in use for more than 75 years.
A water-borne preservative, it offers timber long-term protection against attack by wood-destroying fungi, insect larvae and termites. Permacure CCA can be used for structural timber, agriculture poles (pine and eucalyptus) and transmission poles.
It is applied by impregnation into the timber by vacuum pressure at a timber treatment plant. CCA can be used for hazard classes H1 to H5.
Permacure CCA, or Chromated Copper Arsenate, is a waterborne wood preservative introduced into wood by pressure impregnation.
The active ingredients are chromium (47.5%), arsenic (34.0%) and copper (18.5%). The extraordinary effectiveness of Permacure CCA as a wood preservative lies in the combined action of these three elements.
Copper has been known since ancient times and is one the most abundant metals in the earth’s crust. It inhibits the reproduction of bacteria and also acts as a fungicide, preventing the growth of many fungi, including Lenzites trabea, Poria monticola and Lentinus lepideus. Copper is used in Permacure CCA as a primary fungicide and bacteriostatic agent. It does not directly kill fungicidal or bacterial organisms, but prevents them from using preserved timber as a potential food source.
During the preservation process, the bivalent copper ions bond to the cellulose and hemicellulose in wood via a redox reaction.
Chromium (often called chrome, though this is more appropriate when referring to the pure metallic state of chromium) is another abundant metal, known to have been used in ancient China by the Qin dynasty thousands of years ago for decoration and weapons manufacture.
When oxidised it has a bright red colour, which has led to its extensive use as a pigment and dye. It is also used an oxidising agent in many redox reactions and in analytical laboratories, among many other applications. Chromium is essential to allow Permacure CCA to penetrate deeply into the wood, and for the arsenic and copper to form permanent bonds with the wood.
The greenish hue of trivalent chromium can be seen in the pale green colour of Permacure treated wood.
Arsenic has been known since the 13th century and has many uses as a herbicide, fungicide and insecticide. Arsenic is used in Permacure CCA as a secondary fungicide, making the wood resistant to even copper-resistant fungi. It also functions as an insecticide, leaving wood resistant to attack from xylophagous and detrivorous wood borers.
The product consists of a range of long-chain hydrocarbons (molecules consisting of a chain of carbon atoms as a backbone, with hydrogen atoms), which form an insoluble barrier against water molecules.
The picture on the left is a scanning electron micrograph of a section of pine, showing the tubular structure of wood. These tubes consist of xylem and phloem cells. Preservatives manufactured by Dolphin Bay penetrate deeply into the structure of wood to ensure lasting protection (see the next photo for contrast).
The picture on the right is a scanning electron micrograph of wood which has not been preserved with Dolphin Bay products, undergoing dry rot. As can be seen, the tubular structures in the wood are fragmented and cracked, resulting in wood that is easily breakable and unsafe.
Timber treated with Permacure CCA can be used where there is low to very high exposure to the elements and weathering. The South African National Standards describes this as exposure levels H2 to H5. H2 refers to timber with limited exposure to the elements, such as timber inside a house or under a roof, whereas H5 refers to timber in direct contact with the ground and fresh water.Permacure CCA must be applied using industrial vacuum-pressure equipment at a timber treatment plant.Permacure CCA treated timber can be used on:
- Structural timber: Used in the construction of homes, e.g. roof trusses, indoor and outdoor decking.
- Agricultural poles: Used in vineyards and orchards. Permacure CCA poles are safe and easy to handle as the preservative is fixed within the timber and does not leach out.
- Transmission poles: Electrification or telecommunications transmission lines.
- Building and fencing.
CCA is the oldest and most widely used wood preservative in the world. Many studies have found it to be the most effective wood preservative. Its broad spectrum of usage and its efficacy makes it a difficult product to replace, and it still offers still the best value for money.It has a service life of up to 25 years, although Permacure CCA-treated wood can last for 40 years and longer.Permacure CCA-treated timber is odourless and easy to handle after treatment, and requires no special equipment during installation.It can be painted, although this is not necessary. If you choose to paint this timber, ensure that you use the correct type of paint.
The cost of Permacure CCA is fairly low compared to the cost of the final product. Nevertheless, it is the most important element of the product, as it ensures that the timber has a long service life.
The price of Permacure CCA is determined by the cost of the raw materials required to manufacture it, and delivery costs. For customers paying a local currency, the cost is influenced by the exchange rate of the country.