Today you can see preservative treated wood everywhere in your life, courtyards, communities, squares, parks, riversides, sidewalks, decks, railings, grape vines, flower boxes, flower stands etc. But why this material become more and more popular recently? One reason is that preservative treated wood furniture can withstand the damp and harsh from environment, The other reason is that it still keep natural wood beauty feature. Unlike solid wood, if directly exposed to outdoor environment, it will be mildewed and cracked after three or five months. The same lumber after CCA anti-corrosion treatment, its life will be extended by 10 times longer.

treated wood patio

Treated Wood, Anti-corrosion wood, It is one kind of wood come with outstanding anti-corrosion properties. Insects and mold can damage wood over time. Treating wood with pesticides can prevent wood from rotting as quickly.

There are 3 types of treated wood, natural anti-corrosion wood, thermally modified wood and artificial preservative treated wood. Usually when we talk about treated wood refer to artificial preservative treated wood, today we take a look at how treated wood is made.

(1) Natural anti-corrosion wood

Red pine cedar, and hardwood pineapple, bala wood. This type of wood does not require artificial preservation, no chemical, and it is non-toxic and eco-friendly.

pineapple wood

(2) Thermally modified wood

We have learn about thermally modified wood in last article, Thermally modified wood also known as physical treated wood, it was thermally modified at high temperature, without any addition of preservatives, completely green.

thermally modified wood

(3) Preservative treated wood

Untreated lumber is placed into a large horizontal treating cylinder. The door is sealed, and a vacuum is applied to remove most of the air from the cylinder, and the wood cells in the process. The preservative solution is then pumped into the cylinder, and the created pressure, The chamber forces the chemical into the wood fibers. The pressurized approach makes sure that the chemical makes it to the core of each piece of wood.

Preservative treated wood

At present, The most common chemical used to treat lumber is CCA preservatives and ACQ preservatives to prevent corrosion. Both are composed of preservative ingredients.

CCA preservative:

CCA wood preservative (mainly composed of copper, chromium, arsenic compounds), is currently recognized as the most widely used, oldest, best performing water-soluble composite protective agent, can be widely used in various industrial materials And wood products, such as pier bridge materials, wooden cooling towers, pile wood, electric poles, sluice wood and outdoor landscape wood, etc., anti-corrosion, insect-proof, termite-proof, waterproof parasite treatment. The service life of the wood treated by this agent can be maintained for more than 50 years.

In 2003, however, the Environmental Protection Agency restricted the use of CCA in residential settings due to health and environmental concerns about arsenic leaching out of the wood. The EPA arranged a voluntary agreement with manufactures of wood treatment chemicals to remove lumber treated with CCA from most residential construction uses. Chromated Copper Arsenate treated wood may still be used for permanent wood foundations, highway construction, fence posts, poles used as structural members on farms, marine construction, and lumber and timber for salt water use.

CCA preservative

ACQ preservative

The most widely used alternative to CCA is alkaline copper quat, or ACQ. ACQ wood preservative is a water-soluble wood preservative made of copper and quaternary ammonium salts.

Copper is toxic to various insects and fungi that might cause decay. ACQ binds to wood fibers very well and allows wood to last decades even when it is in contact with the ground.

ACQ wood preservatives, unlike CCA, do not contain substances that are toxic to humans (such as arsenic, chromium, etc. contained in CCA wood preservatives), which are banned in civilian use in Japan, the United States and the European Union.

The life of wood treated with ACQ can reach more than 40 years.

ACQ preservative

The chemicals in treated wood are generally not good for human health. This is why you see warnings advising you to wear gloves, avoid breathing the sawdust, and refrain from burning treated wood to prevent potential risks.

4 Steps for preservative treated wood manufacturing process

preservative treated wood manufacturing process
Step 1  Vacuum Air

Removed the air from the treating cylinder by Vacuum pump.

preservative treated wood manufacturing process

Step 2  vacuum high pressure impregnation

This process is a key step in the preservative treatment. Transfer the treatment solution from a storage tank to the cylinder.

The treatment solution consists of water and preservatives that are designed to help protect the wood from bacteria and insects and termite attack, effectively improves the outdoor anti corrosive wood performance.

Once the cylinder is completely full with the treatment solution, the next step is to pressurize the cylinder using a pressure pump. The increased pressure in the cylinder forces the treatment solution into the wood.

Stage 3  High temperature qualitative

Penetrate the preservative to the interior of the wood as evenly as possible by high temperature, chemical reaction between the active ingredients of the preservative and the starch, cellulose and sugar in the wood continues, Further destroy the bacteria and insects that cause wood decay.

When the pressure cycle is complete, the next step is to transfer the remaining treatment solution back into a storage tank.

Step 4  Naturally dry

Once complete, the door is opened and the preservative treated wood start natural dry, This process is to adapt to the changes in the structure of wood cells caused by environmental changes in outdoor.

Watch the video how preservative treated wood is made.