Understanding Hazard Classifications of CCA Pressure-Treated Timber

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CCA Pressure-Treated Timber

CCA pressure-treated Timber is a sustainable building material that is most preferred by many builders because of its durable qualities and other benefits such as cost-effectiveness compared to other building materials.

CCA pressure-treated Timber is versatile and suitable for various applications. However, each application presents unique risks that affect the wood’s longevity. Consequently, a Hazard class guide has been established to ensure appropriate treatment for different applications.

Emphasizing its significance, I cannot overstate the importance of using CCA pressure-treated Timber solely for its intended applications. When utilized correctly, this wood has the potential to endure throughout your lifetime.

In this article, we will explore the different hazard classifications of CCA pressure-treated timber. This will to help you to choose CCA-treated wood that is best suited for your project:

Understanding the CCA Hazard Classifications System

The South African Wood Preservation Association (SAWPA) and the South African Bureau of Standards (SABS) have collaboratively established a comprehensive hazard classification system tailored for wood treatment. This system takes into account the intended use of the timber. This information will then influence the chemical penetration and retention levels of the CCA solutions employed.

Level of Penetration and Level of Retention

The level of penetration refers to the extent to which wood treatment chemicals permeate the timber. Conversely, the level of retention pertains to the amount of treatment chemicals remaining in the timber after the treatment process. Retention levels are typically expressed in terms of the concentration of active ingredients present in the timber.

Distinct CCA Hazard Classifications of CCA-Treated Timber

CCA treatment hazard class guide

There are four commonly recognized hazard classes for CCA-treated timber, labeled as H2 to H5. It is crucial to understand these classes to ensure the maximum quality and durability of the timber. Let’s explore each hazard class in greater detail:

Hazard Class 2 – INTERNAL (Low hazard):

This classification is exclusively intended for interior applications where it will not be exposed to moisture or any wood-destroying elements.

Timber treated under this category finds its use in; aminated beams, structural timber for internal use, ceiling boards, flooring, paneling, doors, cupboards, skirting, window frames, and plywood.

door built with treated wood

Hazard Class 3 – EXTERNAL, ABOVE GROUND (Moderate hazard):

CCA-treated timber falling under this hazard class is suitable for above-ground, external use. Cladding is utilized on the exterior where it comes into contact with weathering elements and insects. However, it is not subjected to prolonged exposure like poles that are inserted into the ground.

Other examples of wood treated with H3 are: balustrades, fencing bearers and slats, outdoor decking and beams, garden furniture, laminated beams, weatherboard, steps, cladding, stairs, log homes, gates, fascia boards, and plywood.


Hazard Class 4 – EXTERNAL, IN-GROUND (High hazard):

This classification is intended for exterior in-ground applications. CCA pressure-treatment at this level helps prevent decay and termite infestation in agricultural posts and landscaping structures.

Examples include agricultural posts, playground structures, fences, pergolas, carports, flower boxes, decks, bridges, and stakes.


Hazard Class 5 – FRESH WATER, HEAVY WET SOILS (High hazard):

This hazard class is specifically assigned to timber that is consistently exposed to moisture or planted in damp soil. In such environments, the wood faces a significant risk from very severe decay, borers, and termites.

Examples of applications are: Piling, house stumps, power poles cooling tower fill, building poles, and retaining walls more than 1m high.

CCA Pressure-Treated Timber

Importance of CCA Pressure-Treated Timber on Coastal Wood Structures

When constructing wood structures in coastal areas, we highly recommend using CCA-treated wood. Timber structures that are build in coastal areas and especially exposed to moisture and other harsh environmental conditions. CCA treated wood can withstand these elements thereby increasing its durability.

Another good reason why CCA treated wood is ideal is because it is resistant to insect attacks. Let’s consider an example: The European House Borer (Hylotrupes Bajulus), is a type of beetle found in the low-lying regions of South Africa. This beetle specifically targets the sapwood of softwood, causing no noticeable symptoms until exit holes start to appear.

It thereby effects the strength and durability of the wood. With CCA Pressure-Treated Timber, this is generally not the case. This is because the CCA pressure-treatment process involves impregnating toxic chemicals into the softwood. It then effectively deters borers from attacking the wood.

CCA Pressure-Treated Timber

Applying Additional Protection to CCA Pressure-Treated Timber

There is a common misconception that applying a protective coating alone provides the same level of protection as pressure treatment. It is important to note that a sealer does not penetrate as deep as CCA-treated wood. Sealants safeguard the timber from weather-related damage but do not protect against insects and fungal attacks.
However, adding a sealant for additional protection would be wise. This is because, over time, the effectiveness of the CCA pressure-treatment may diminish, especially in high-exposure areas.
Applying additional treatments periodically extends the lifespan of the wood. This ensures continued protection against deterioration and preserving its structural integrity.

At Sabie poles, we supply sealants that are 100% compatible with all our wood products.

CCA-Pressure treated Timber at Sabie Poles

At Sabie Poles, we supply and export quality wood that is CCA-treated and untreated. Our Structural Timber and Timber Mouldings (namely; Decking, Ceiling, Flooring, Cladding, architrave, and Quarter-rounds) are primarily treated with Hazard Class H3. Our Building and Fencing Poles undergo Hazard Class H4 treatment, making them suitable for various applications.

We export to all SADC Countries and Internationally. We offer our products at all BUCO stores and can arrange delivery.

Accreditations and Quality Assurance

We pride ourselves on exceeding the minimum requirements as a CCA Pressure-Treated Manufacturer and supplier. All our CCA Pressure-Treated products bear the SABS and NRCS’ stamp of approval. This which indicates compliance with necessary specifications and regulations. These prestigious endorsements validate our commitment to meeting and surpassing industry standards.


The appropriate level of chemical treatment needed to protect wood against insects and fungi relies on using the hazard classifications of CCA-treated timber. These classifications take into account the intended use of the timber, the depth of chemical penetration, and the level of chemical retention.

Understanding the hazard classifications of CCA pressure-treated timber is essential for selecting the right type of wood for specific applications. By considering factors like hazard class, level of penetration, and level of retention, you can ensure the durability and longevity of your wood structures.

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