Timber foundations are a crucial part of a timber structure. the part where the timber foundation stands on is just as important, it should be able to handle all the weight of a timber structure.

It is quite obvious that as time goes by, bigger, better and more technical structures are being built. These structures prove just how versatile timber is. Furthermore, when you combine science with timber, you’ll realize just how much strength timber can have. I once saw a video on LinkedIn where the engineers built a bridge using timber only, with no screws or nails, timber only. To test the strength of the bridge, they drove an SUV vehicle over it. The bridge was so strong, it looked like it carried that SUV vehicle without any effort at all. Now let’s get back to the topic.

The fact of the matter is, that timber, if used in the right ways, can be exceptionally strong. In this blog, we will discuss the use of CCA-treated poles as piles for timber foundations.

What are timber foundation piles?

Piles refer to long, slender posts driven into the ground to provide a stable base for structures. They act like anchors, transferring the weight of the building down through soft soil or water to a layer of firmer soil or rock below.

2 Main benefits of using CCA-treated poles as timber foundation piles.

Stable Support

In Africa, many structures, especially lodges in remote locations, are built on challenging terrain. Uneven slopes and soft coastal soils pose unique construction problems. CCA poles offer an effective solution. Their variable lengths can accommodate these uneven ground conditions, providing stable and reliable support to securely anchor structures.

Natural Strength

In South Africa, you’ll find two species of poles that are treated with CCA namely Pine and Eucalyptus(gum). Pine poles can be used in construction however, there are limitations. Eucalyptus (gum) poles are mostly used in construction, especially in heavy load-bearing applications. Eucalyptus Gum poles consist of their natural strength. The inherent strength of these poles is primarily due to the distinctive properties of eucalyptus wood. Eucalyptus species are characterized by their high density and hardness, which contribute significantly to the wood’s structural integrity. The dense, compact nature of the wood fibers ensures that the poles are solid and capable of supporting substantial weight.

Note that CCA pressure treatment does not influence the strength of timber but increases its durability by protecting it from elements such as weather, rot, decay, and insect attacks.

The typical lifespan of CCA poles used as timber foundation piles.

Under typical conditions, CCA-treated timber foundation piles can last between 40 to 70 years. In some cases, especially where conditions are less severe, they can last even longer. For example:

• Normal Soil and Climate Conditions: In typical soil and climate conditions, CCA-treated piles can easily last 50 years or more.
• Challenging Conditions: In harsher environments, such as in waterlogged areas or very acidic soils, the lifespan might be on the lower end of the range, around 40 years, but this is still significantly longer than untreated wood.

Proper maintenance and periodic inspections can help in maximizing their longevity.

The most used pole sizes used for timber foundation piles

CCA pressure treated poles used as foundation piles come in various sizes to accommodate different structural requirements and soil conditions. The most commonly used sizes for CCA-treated foundation piles typically vary in diameter and length, with specific dimensions chosen based on the load-bearing needs and the type of structure being supported. Here are some of the typical sizes:

Diameter

• Small Diameter Poles: These are usually around 120 mm – 200mm in diameter. They are suitable for lighter structures or use in residential construction.
• Medium Diameter Poles: These poles range from 200mm to 300mm in diameter. They are commonly used in moderate load-bearing applications, including small commercial buildings and larger residential projects.
• Large Diameter Poles: Poles with a diameter of 300mm and above. These are used for heavy-duty applications, such as in industrial construction, bridges, and large commercial buildings. Finding poles with a diameter of 300mm or greater can sometimes be challenging. However, Sabie Poles can fulfil these special size requests.

Length

• Short Poles: Typically, 3m to 6m in length. These are used for shallow foundations or areas with less soil depth.
• Medium-Length Poles: Usually range from 6m to 12m in length. Suitable for standard building foundations where moderate depth is required.
• Long Poles: Poles longer than 12 meters. These are used in areas with deep foundations or where the soil conditions require deeper penetration to reach stable ground. At Sabie poles, we supply poles with lengths of up to 15m.

Factors Influencing Size Selection

1. Load Requirements: Heavier structures require larger diameters and longer poles to provide adequate support.
2. Soil Conditions: Soil type and conditions (e.g., sandy, clay, rocky) influence the necessary length and diameter to ensure the poles reach stable ground and can adequately support the structure.
3. Local Building Codes: Regulations and building codes may dictate minimum sizes and treatments for foundation piles to ensure safety and compliance.
4. Design Specifications: The specific engineering design and architectural requirements of the project also determine the appropriate size of the poles.

The treatment of CCA timber foundation piles

CCA poles used as timber foundation piles are treated to Hazard class H4 due to the demanding environment they endure. This H4 classification signifies treatment for wood in direct ground contact and exposed to high-hazard conditions. Foundation piles are constantly buried in the earth, facing constant exposure to moisture, rot, and insect infestation.

The H4 treatment for CCA poles ensures they can withstand these threats and provide the critical support needed for structures.

However, it’s important to remember that local building codes or project specifications might have specific requirements for CCA classification in foundation piles.

Always consult with a structural engineer or your local building department to confirm the exact CCA classification needed for your project.

Sabie Poles, supplying you with what you need.

When it comes to timber construction, we have all the materials you need. All our products are SABS-approved and treated according to all required specifications. Our products meet national standards.  

Here’s the bonus: We export our poles and timber to all SADC Countries and internationally. So, no matter where you are. Contact us to assist you. Contact us directly or simply fill in a form and we will get back to you, to fill in the form, click on the following link: Contact us