Timber and the CCA pressure treatment process

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CCA Treated

CCA-treated timber has emerged as a significant advancement in the Forestry Industry, gaining popularity among construction projects as more individuals opt for timber as their preferred building material. Architects worldwide continue to favor timber due to its numerous benefits.

Given the pressing issue of global warming, the utilization of CCA-treated timber can have a profound impact. Timber is derived from a naturally renewable source and possesses the ability to store a substantial amount of carbon for as long as it is in use. As carbon emissions stand as the primary contributor to global warming, using CCA-treated timber presents a valuable solution. (Read more about this: Forest sustainability and timber).

What is the preservation of timber?

Timber preservation is the treatment of timber to protect it from wood destroying agencies such as rot, decay, insects and weathering thereby increase its durability by at least 25 years.

The effectiveness of the treatment is based on the following:

  • Whether it is treated with the correct biological hazard class to endure the conditions the timber will be exposed to.
  • Whether the chemicals used are potent enough to protect the timber against destroying organisms.
  • The penetration and retention of preservative chemical, i.e. the extent of the penetration of the preservative chemical into the cross-section of the timber and the amount retained in the penetrated zone per cubic meter of the timber.

What is CCA?

CCA is the abbreviation for Chromated Copper Arsenate, it contains compounds of 47.5% chromium (CrO3), 18.5% copper (CuO), and 34.0% arsenic (As2O5).

Every element of the mix serves a certain purpose:

  • Copper resists rot or decay caused by fungal attacks.
  • Chromium fixes the preservative to the cell walls in the timber so it doesn’t leach out.
  • Arsenate resists attack by insects such as borers and termites.

In South Africa, CCA Type C is used as it is internationally recognized as the most stable and effective type, i.e., apart from its efficacy as a timber preservative.

You can only CCA to timber using industrial high-pressure processes from where the familiar term “pressure-treated wood” hails. The manufacture and distribution of CCA is regulated by the Registrar Act 36 of 1947 and it is registered as an agricultural remedy under the category “Wood Preservative.”

What is CCA used for?

You can only use CCA as an industrial wood preservative as stipulated by the National Regulator for Compulsory Specifications (NRCS) approved and SABS or SATAS-certified industrial wood preservation plants, i.e., under-regulated and controlled conditions. CCA-treated timber is governed by the Department of Trade and industry.

We treat our wood according to different hazard classifications, ranging from H2 (dry interior above ground) to H5 (heavy wet soils and freshwater), and for H6 (Marine contact) when used as a dual treatment with Creosote.

Identifying CCA Treated Timber

You can identify CCA timber by its yellow/greenish to green colour that fades over time into a weathered silver-grey if exposed to the elements and not maintained with wood finishing protective product i.e., a suitable exterior sealer. 

Structural Timber
Greenish tint on wood

Preparing timber for the CCA treatment process

When we harvest our trees at the plantation, we choose only the best quality eucalyptus poles for the treatment plant. Our operators and other team players in the plantations fully equipped themselves while adhering to all the necessary South African harvesting rules.

Bark strippers will initially strip bark from the upright tree by pulling the bark from bottom to top, thereafter Chainsaw operators will cut down the tree, and once it lays on the ground, it is safe for people to work in the vicinity of the fallen tree, the bark strippers will remove the excess bark from the logs.

Manual debarking

Manual workers will debark the trees using a sharpened hatchet. They detach the bark either as long or short strips or small plates. For debarking they use Debarking spuds (a hoe-type piece of equipment) or shaped spades.

We leave the debarked trees (poles) in its natural state for approximately 2 weeks for the moisture to escape and for the cellulose to settle.  Once we see the poles have reached the desired moisture content, we start with the grading process. Afterwards, a checker will mark the log at the required lengths for the chainsaw operator to cut the log into a pole. 

Then we transport the wood to the Sabie Poles CCA Pressure Treatment Plant. Our quality control team at the treatment plant ensures that they accept only the best Eucalyptus poles.

Grading and quality control system

when we grade our timber, we ensure that it meets the required specifications to withstand certain challenges and adhere to specific safety purposes as set out in SANS 457/1288. A complete set of timber quality standards were developed and maintained over the last 7 decades by South African National Standards and industry players. 

These standards ensure uniformity across the industry. It is important that construction workers ensure the timber is suitable for their project’s/product’s end use.

When the poles enter the treatment plant territory, we grade it once again before we start with the treatment process. We treat them according to the following criteria:

Grading criteria before Eucalyptus pole treatment 

  • The poles must be straight
  • The poles must have the correct diameters
  • There should only be standard allowable cracks/splits with no spirality in the wood.
  • Knots should be tight and not protrude
  • There should be no sign of bark
  • The poles must not have physical damage, such as chainsaw cuts
  • The poles must have a sapwood of 13mm and more, but sapwood must not be more than 80% of diameter as this will weaken the pole.

Moisture Content and Drying

Drying is a key step in the process. Optimal drying before treatment is necessary to allow maximum absorption of the CCA chemicals. 

Air drying

we stack the timber with spaces in-between each other – usually, we stack the first layer from north to south and the next layer from east to west. We call this method air stacking.

Moisture from the interior of the timber generally moves to the surface. When air passes through the surface of the timber, it can pick up moisture and carry it away, thus leaving the surface of the timber slightly drier than it was before. We call this method air drying.

Drying times:

Drying times vary widely from 2 weeks to several months depending on species, dimensions, local weather conditions, and the time of year the material is stacked. When the moisture content has been reduced to the so-called “fibre saturation point” of approximately 25-30 percent (250 -300g/Kg), all free moisture has been removed from the voids in the wood (moisture held within the cell cavity) and the residual or bound moisture is contained in the cell walls only. 

Seasoning (of the bound moisture) below the fibre saturation point dries the cell walls and shrinkage may occur.

Air drying is the best way to control moisture in timber. Storing any sawn timber in a clean and dry area or stacking it on raised foundations will allow nature to take its course. The wood will eventually adopt the same moisture level as the air around it.

Kiln drying

We stack the timber in an insulated building or kiln where drying conditions are artificially produced by strict control of temperature, humidity, and airflow.

This method of drying can reduce the moisture content of timber to any predetermined level in the optimum time and with minimal drying defects and loss through checking, splitting, collapse or deformation. The moisture content of a piece of wood is always expressed as a percentage of the “dry weight” of that timber.

We dry our timber for the following reasons:

– Stability

– Maximum strength

– Decrease weight

– Reduce susceptibility to fungal attack

– Prepare it for preservation

Testing timber for moisture

Moisture content can vary between apparently similar pieces of the same species and in addition, there may be differences, between and within species, in the rates at which moisture is lost from timber during drying.

These inherent differences in timber mean that it is important during the drying process to be able to monitor moisture content and check that the drying process is proceeding correctly. Use practice this method using a moisture meter.

The standard moisture content of wood stands between 8% and 25% by weight. Kiln-dried wood usually shows a moisture reading of 10% on the outside and then 25% on the inside. The moisture content overall is almost always below 20%. ( average moisture content of pine timber should be 12%)

Moisture meter
Example of a Moisture Meter

CCA pressure treatment process

Pressure treatment processes are the most permanent method of preserving timber life today. a higher absorption of the preservative is achieved as well as a deeper and more uniform penetration using this method.  

Before treatment

We take the following steps before the timber goes in for treatment:

  • The person responsible for loading present counts the timber/pols.
  • We then treat the timber/poles with the correct retention and hazard class in mind.
  • We also mark the timber/poles for moisture control and sapwood penetration.
  • Before each charge we take a titration test to determine the concentration of the solution
  • We also check for any leaks or breakages of pumps, if any are visible, we notify the representative manager. 

Different Hazard Classes and their end-uses

The higher the hazard number, the greater the risk to the wood and the higher the chemical loading required. When buying timber in South Africa you can choose between five different hazard classes.

If South African timber suppliers want to guide buyers to make the best possible purchase decisions, they will need to know how the buyer wishes to use their wooden poles. Suppliers of CCA poles would do well to stock a wide variety of bulk timber for sale. This applies to sizes as well as different Hazard classes. 

At Sabie Poles, we offer Tanalized CCA-treated timber and poles in the following hazard classes: 

Hazard Classes

  • H2 – Suitable for internal applications which are not in contact with the ground. 

Examples are: 

–         When using Structural Timber; Laminated beams, roof trusses, ceiling, flooring paneling, doors, window frames, etc.

  • H3 – Suitable for external applications above ground. This timber can come into contact with the elements (weather), but not with the ground.

Examples are: 

–         When using Poles; Cross-arms and spacers, fencing rails, pergolas, playground structures, carports, vine trellises, droppers & laths, poles longer than 5.4m used for thatch roofs, etc.

–         When using Structural Timber; Balustrades, gates, steps, Outdoor decking, garden furniture, cladding, flooring, etc.

  • H4 – Suitable for in-ground contact applications. These poles can withstand decay well so it can come into contact with the ground.

Examples are: 

–         When using Poles; Rail bearers, agricultural poles, guard rails, playground structures, fencing, etc.

  • H5 – Suitable for wet soils or even in-water applications. Able to withstand severe decay and can handle wet conditions.

Examples are: 

–         When using Poles; Agricultural poles under drip and flood irrigation, bridges, piling, walkways, slipways, livestock pens, retaining walls, etc.

H6 – Suitable for application in sea (salt) water. Wooden poles in this hazard class can stand up to marine decay.

Examples are: 

–         When using Poles; Piling, retaining walls, slipways, groynes, jetties, and walkways.

We are proud to say that all our treated timber poles have SABS approval. We mainly treat our timber poles with H4, H5, and H6 treatment. Poles such as the droppers, and laths are treated with H3 treatment. For safety and quality reasons, we do not treat any of our timber with H2 treatment.  

Pressure treatment process

The pressure treatment process starts by transferring untreated timber/poles into the treatment cylinder. Once inside and adequately sealed. We use the Bethuel Full Cell method:

Step 1

Fill the cylinder to 90% with a solution.

Step 2

a Vacuum pump removes all the air from the treating cylinder. This takes approximately 5 minutes.

Step 3

Fill the cylinder to capacity with the CCA solution.

Step 4

With the use of a pressure pump, the cylinder is pressurized. The increased pressure forces the solution into the timber for the required retention.

Step 5

Next, the remaining treatment solution is transferred back into a storage tank.

Step 6

a Final vacuum is initiated for 15 minutes and the remaining solution is pumped into the working tank

Step 7

Take a final measurement after the overflow process.

Finally, the cylinder will be opened and the timber will be moved.

After treatment

At Sabie Poles, the timber will mainly have been treated with either H3 or H4 treatment.

Timber is moved and tested

After treatment, the timber is moved to an inspection ramp where every pole is measured and timber will be taken for testing. Testing is done by drilling into the timber with an increment borer; this method enables the tester to see how deep the chemicals have penetrated the timber. As mentioned above, the minimum penetration should be 13mm deep in the case of poles.

If the tests show that the penetration has not met the requirements expected, the whole treatment process needs to be repeated.

Once the test result shows all standards have been met, it’s approved, then permission will be given to mark the products.

Marking timber

The poles are marked with anti-split plates and Omni markers plus Colour Code for the different dimensions of the poles.

  • The Anti-split plates have to cover at least 80% of the timber.
  • The plates need to have the Year of treatment, Hazard Class, Business Trademark (STP- for Sabie Poles), and SABS Approved stamped on them.

– Once the timber is marked, it will be stacked respectively according to length and width.

Allowing timber to dry

The treatment of timber with water-borne preservatives reintroduces substantial amounts of water into the wood.

Re-drying is less critical in commodities such as fence posts or transmission poles than it is in sawn timber where dimensional stability and painting of the treated timber could be required.

However, where treated timber is to be used in building construction or for playground equipment or decorative landscaping purposes, it is recommended that the freshly treated timber be allowed to dry until the surface of the timber is dry to the touch before being transported from the treatment site.

Provided common-sense precautions are observed, preservative chemicals do not present a hazard to humans once fixed in the dried timber.

This takes about  7 days.  Sometimes a white powder will appear on the surface of CCA-treated timber. This is mostly sodium sulfate, a harmless substance that, if necessary, can be simply brushed or hosed off.

Health And Safety

– According to SAWPA, no monitoring by any authority in South Africa over the past decade has produced any evidence to suggest that commercially used preservatives are damaging to individual health or to the environment.

– The chemicals used for the protection of the timber are toxic to certain living organisms; however, the risk to humans is at a minimum as long as the timber is treated correctly. If treated correctly, following SANS 1005 regulations, the chemicals should not leach from the timber, as it will either be chemically bonded to it or physically immobile. 

– Impacts on human health depend on the type of chemical, whether we are exposed to the chemical by eating or drinking, breathing or absorbing it through the skin, and the period of exposure. 

The work environment

– Proper design and safe operation of the timber preservation plant are critical. Environmental factors need to be taken into consideration when selecting a site, designing the treatment area, storage and handling facilities for chemicals and treated wood, and managing waste. 

– Safe handling, machining, and transportation of the treated wood are important as workers can be exposed to the chemicals in the wood. Under some circumstances, chemicals can slowly escape into the environment. To reduce the impact of wood treatment on health and safety and the environment, the South African Wood Preservation Association (SAWPA) developed practical guidelines for safer practices in industrial wood preservation, which has now culminated into SANS 10255, “Health, safety, and environmental guidelines for the construction and operation of timber treatment plants”. The aim of the standards is to help reduce the exposure of workers to chemicals and to reduce or prevent the release of pollutants to the environment. 

4 Main safety precautions for CCA treated wood

Treated timber is significantly less hazardous than scores of items the public handles daily. If any risk is involved, it can be virtually eliminated if treaters ensure that at the time of distribution, the surface of the product is dry and free from preservative deposits or exudates.

The following safety measures should be taken:

1. Light gloves should be worn.

When you’re working with any type of wood, treated or untreated, it is wise to use gloves to avoid cuts and splinters. When you are working with treated timber, it becomes more important. A simple splinter from pressure-treated timber might result in a small infection. If you are unable to get the splinter out and the pain is persistent, we recommend you visit a doctor for the removal.

2. During any form of woodworking that generates dust e.g. sanding, respiratory and eye protection and a mask should be worn.

When you are working with CCA Treated Wood, it is always necessary that everyone in close proximity should wear a mask. This applies to everything from sawing and drilling to cutting the treated timber. This not only applies to treated timber, but also to any type of untreated timber.

Even when working with untreated timber, the dust from the wood can result in serious health effects. This is due to the fine dust particles that make their way into your lungs.

3. You should never burn treated wood waste in a barbecue or confined space.

You should only use treated wood as intended. If no re-use applications are available you should dispose of them at either a registered landfill site or waste disposal site, from where they will be disposed of by a registered landfill.

CCA-treated timber waste, i.e. demolition waste and/or off-cuts must never be burned for disposal, heating, or cooking purposes as it releases the fixed components which contain toxic and harmful substances. The aforementioned disposal methods apply.” – SAWPA

4. Wash your hands and face with soap and water before eating, smoking, and use of the toilet. 

Signs of exposure to CCA treated wood chemicals

If you are worried that someone might have been exposed to the harmful chemicals in CCA Treated Timber, always visit a doctor as soon as possible.

The most common symptoms of exposure to pressure-treated wood are as follows:

  •  Itching
  • Burning rashes
  • Neurological Symptoms
  • Nausea
  • Thirst

NOTE: Please do not self-diagnose. Always visit your doctor to confirm if you suspect any type of poisoning.

What NOT TO DO with CCA-treated timber

For safety reasons, you should not do the following:

– Make baby toys or furniture from CCA-treated timber that infants can chew on.

– Use CCA-treated timber for firewood or prepare food on it.

– Store food in direct contact with CCA-treated timber containers.

– Make food utensils for storing or drinking water from CCA-treated timber.

– Use CCA-treated timber in beehives where it may come into contact with honey.

– Use treated timber shavings or sawdust for animal litter or where it can become a component of animal feed.

CCA treated timber is environmentally friendly

When you select CCA-treated wood you not only build projects that last, you invest in the conservation of our forest resources. CCA-treated wood will last much longer than it takes replacement trees to grow and be converted into wooden products, thus extending the life of wood and whilst requiring fewer trees to be cut, furthers the carbon sink of the carbon captured in the wood when the tree was growing.

Life Expectancy of CCA Treated timber

Depending on the climate, the type of wood, its uses, and how well it’s maintained. While pressure-treated poles can stay up to 40 years without any signs of rot or decay. We have a lifetime guarantee on all our CCA-treated timber products.

Staining CCA Treated Timber

CCA-treated timber is already protected against various elements such as weather conditions, insect attacks, fungi, rotting, and decay, to name a few. However, applying stain and sealant to pressure-treated wood adds an additional level of protection that homeowners don’t want to be without. Staining also prevents it from cracking and splitting when seasons change.

The appearance of the wood can be enhanced and protected by the application of a surface coating of paint, stain or water repellent. Unlike most other wood preservatives, CCA readily accepts coatings and can actually help to increase the service life of some finishes.

Here are a few tips:

Most paint, varnishes and solid-color stains are not recommended for exposed horizontal deck surfaces, pressure-treated or untreated, because they are film-forming coatings, they have a tendency to peel, blister and mark when subjected to weathering and traffic.

Clear or pigmented water repellents, wood toners and semi-transparent stains are the finishes most often used on either treated or untreated timber. To work properly they must be able to penetrate the surface

It is important to seal the treated timber after it has been stained. By sealing it you protect the wood from elements such as water damage, weather and scratches.

At Sabie Poles we recommend using Timberlife products for CCA treated wood:

At Sabie Poles, Our CCA-treated is already protected against various elements such as weather conditions, insect attacks, fungi, rotting, and decay, to name a few. However, applying additional treatment such as sealant to pressure-treated wood adds an additional level of protection that homeowners don’t want to be without.

Here are a few suggestions:

  • UltraSeal is a Timberlife penetrating solvent-borne sealer that provides a durable high-sheen finish with good flexibility. UltraSeal is particularly suitable for use on exterior timbers such as wooden windows and doors. 

UltraDeck is also a Timberlife penetrating solvent-borne sealer that provides a durable high-sheen finish with good flexibility. It is particularly suitable for use on exterior timbers such as wooden decks and walkways. 

Both contain a unique blend of drying oils, high-quality resins, water-repellent wax components, and UV-resistant transparent iron oxide pigments. Both of these products are available in Teak, Golden Brown, Deep Brown & Oak.

  • CTX 108 is a Timberlife ready-to-use organic solvent-based solution that contains a specific blend of insecticidal and fungicidal active ingredients. This provides a colourless surface treatment for the protection of seasoned timber against wood borer, termite attacks, and discoloring fungi and mould growth.
  • Khuni Sealer is an oil/wax-based penetrating sealer that protects raw (uncoated) wood against water ingress, surface degradation, and contamination. The high-quality blend of drying oils and water-repellent wax components deeply penetrates, stabilizes, and nourishes the wood. It, therefore, acts as a transit stabilizer, and protective sealer that prevents excessive checking and splitting of pre-manufactured timbers during building construction.

We have CCA Treated timber products available at Sabie Poles

CCA Treated Poles

CCA Treated Poles is a great timber product to use for both domestic use and commercial use. They are ideal for anyone that is looking to build something that will last without any extra maintenance. These treated poles can last anything from 20 years (minimum, when you use them in suitable applications) to longer if you have taken extra precautionary measures like staining and sealing it again before using it. 

Sizes available are:

  • 32mm -49mm : 1.2m – 3.0m
  • 50mm – 74mm : 1.2m -6.0m
  • 75mm -99mm : 1.2m – 9.0m
  • 100mm -124mm : 1.2m -15m
  • 125mm -149mm : 1.2m -15m
  • 150mm – 174mm : 1.2m -15m
  • 175mm -199mm : 1.2m -15m
  • 200mm – 224mm : 1.2m -15m

Laths & Droppers

You can use laths for weaved baskets or for other decorative purposes. You can use laths to prevent the reeds from falling of a thatched roof.

We stack our in bundles of 10 and come in lengths of 3.0m, 3.6m and 4.5m with a diameter of 20-32mm on the thin side. 

Droppers are thicker than laths and and you can use it in all types of fencing. Whether it is to simply enclose space like a swimming pool etc. or use it as additional support for fencing around an agricultural land or game farm. we treat them to class H3. Therefore, it will be able to withstand outdoor conditions.

They are available in the 1.2m, 1.5m, 1.8m, 2.1m, 2.4m, 2.7m and 3.0m lengths with a small end diameter of 32-49mm.

Slabbed Bearers

Also known as Milled Logs, we cut them round with two flat edges to allow effortless stacking. Slabbed bearers have many uses. Building your log home with slabbed bearers is ideal, they can still give that charming feeling of a log home without all the hassle of fitting each log perfectly together.  You can use Slabbed bearers as pathways in gardens or on a tank stand as horizontal support for a water tank.  Some people use slabbed bearers to make rustic furniture and table tops.  Slabbed bearers are ideal to use as support for timber flooring in a double-story house. 

Square-cut Poles

We treat our Square cut poles with an envelope treatment. Thus, you can only use these poles under roof, above ground. No Ground Contact. You can use them for decorative purposes like pillars under a veranda roof. you can also use them as beams or roof rafters. Please read our blog on the do’s and don’ts of how to use square-cut poles.

Structural Timber / S5 Construction timber

Building Materials need to be of the highest quality. You should use timber graded according to the specifications and regulations enforced by the South African safety law for construction purposes. Our structural timber materials are SABS approved, under the “S5” Construction grade timber. Our timber is suitable for big and small projects.

You can use structural timber for; Laminated Beams, Roof Trusses, Structural Timber under decking or timber homes, Boards, Flooring, Panelling, Doors, Cupboards, Skirting, and Window frames. 

Available Sizes are:

  • 38mm x 76mm
  • 38mm x 152mm 
  • 38mm x 228mm
  • 50mm x76 mm
  • 50mm x152 mm
  • 50mm x228 mm

Lengths: 3.6m, 6m & 6.6m

Timber Mouldings

Decking – While the most obvious use for timber decking is building a deck, you can use it all over your home and garden to create unique and beautiful spaces. You can apply Additional products such as stains and varnishes to ensure that your timber deck will last a lifetime. We have two textures of decking available namely plain and non-slip.

Sizes available are:

22mm x 106mm 

32mm x 106mm


 Timber ceilings provide very good acoustics and soundproofing performance. It is an excellent option for social spaces, which include public or office spaces. Timber ceilings have air pockets that are naturally in the wood’s grain. Within the cellular structure, it retains cold and heat.


You can use Cladding for specific interior or exterior finishing. Or you can build a timber home or perhaps to create an accent wall, or to finish off a stylish room. In construction, you can use cladding for  thermal insulation and weather resistance, and to improve the appearance of buildings. You can stain or paint it to your preferred colour to match your interior. There are various styles of cladding available but at Sabie Poles, we deal with the half-log (shiplap) cladding profile. Half log cladding has a curved profile to the front of the timber, giving it the ‘log’ effect, and is flat on the back and is ideal for log cabins, garden rooms, summerhouses and garden sheds.

Sizes available are: 

  • 22mm thickness x 102mm width
  • 32mm thickness x 102mm width


A floor needs the best strength and durability as it has to withstand all the punches and pressure created by day-to-day human activities. With the correct care and maintenance, you can expect a timber floor to last for decades.

Pine flooring is highly durable and around the country, pine floors 100 years old or even older are still in use today. A pine floor will serve you well for the full life of your home. Pine rarely has problems with shrinking or swelling, although, in a humid climate, it will benefit from a coating of polyurethane.


You can use mouldings for doors and windows. Or you can use it for decorative purposes or to hide gaps between the wall and a door/window frame. Sizes available are: 22mm x 102mm

Quarter Rounds

Ideal for adding that finishing touch to your flooring. You can install quarter rounds between the base of a wall and the flooring and cover up gaps and imperfections. Available sizes are: 32mm

All our CCA-treated products have the SABS and NRCS stamps of approval. Furthermore, we have certification and membership with some of the top contributors in the CCA Manufacturing and forestry bodies like SAWPA (South African Wood Preservers Association).

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