Using wood in water applications

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Wood in Water

Wood is a beautiful and versatile renewable, recyclable natural resource. It is energy-efficient and most importantly, it stores carbon. Wood stores carbon for a longer period of time. This gives wood an important role in reducing carbon emissions. We need to motivate consumers to use wood in their construction projects rather than other kinds of material. Some construction projects require wood to be in the water.

The big question is, can we use wood in water and how long will it last if placed in water?

The use of wood in water

Generally, all wood absorbs water to a certain degree, however, the amount of water it absorbs depends on the species of the wood. It’s mostly about the grain of the wood, with open-grained woods absorbing more water than closed-grained woods. 

At Sabie Poles, we deal with the Eucalyptus Grandis tree species, a hardwood, for our timber products for underwater-under-ground contact. There are various reasons why Eucalyptus is the best hardwood option for construction.

Water is known to be a true friend to Eucalyptus Grandis, according to Wikipedia, “It is the dominant tree of wet forest and rain forest margins.” Even though these trees love water so much, it is still very important that it is treated for protection against weathering conditions and wood-destroying organisms. 

How the Eucalyptus handles water

It is never a good idea to plant an untreated Eucalyptus pole in the water. If it is untreated and used in wet conditions, it will start to rot significantly faster than CCA treated poles.

Though it handles water very well, it is still exposed to wood-destroying organisms. The pole will remain solid under the water, but once it is exposed to air, it results in rapid deterioration of the pole. The wood will start rotting from the inside above the water level while the lower part of the pole will remain solid. This is because the combination of water, sun and oxygen is the perfect recipe for causing the wood to rot. 

When Eucalyptus poles are subjected to the CCA Tanalised pressure treatment process, it is protected against wood-destroying organisms such as insects and weathering conditions. Our poles at Sabie Poles are treated with Hazard Class 5 for use in wet conditions.

Additional protection is added to make the treated timber more water and weather-resistant.

You should know that nothing beats Mother Nature, any building material you may choose can get damaged due to the weather elements. For wet applications, CCA treated timber always wins as being the best option.

Piles in water

5 Main reasons to use wood in water

–              Steel, which is a common building material, is highly susceptible to corrosion caused by water. It will rust and debris will be released into the water.

–              If completely exposed to the sun, plastic eventually becomes brittle. The UV radiation in the sunlight interacts with the carbon bonds in the polymer and breaks them down over time. Plastic is not a natural resource.

–              Our CCA Tanalized timber is specially treated for under water-in-ground contact. With our treatment process, our timber is strong and highly durable.

–              Timber is a natural resource, if a pole reaches the end of its lifetime, it decays and becomes part of nature once again, so there are no environmental issues.

–              Timber is an optimal storage place for CO2. As long as a pole stands, carbon is locked away. This makes the role of timber use in building applications around the world very important. 

Bridge over water

Top 6 Wood in water applications

For timber to last in wet conditions, it should be treated with Hazard Class 5 CCA. There are many in-water applications for timber. Over time we have realized that there are a few favourite applications for timber. Here are 6 top uses:

Cattle Pen and feeding lots

Cattle farming are a popular way to make a living in South Africa. Generally, there are two different kinds of pens namely Holding pens and sorting pens. Not just any wood can be used for cattle pens and the wood that is used should be treated. You can read more about constructing a cattle pen here: Cattle Kraal Pen Construction

The wood used for Cattle pens and feeding lots will be moist most of the time. The moisture is caused by rainy weather and mainly cattle urine. If the timber is not treated, it will rot exceptionally fast. When the timber is CCA Pressure Treated, the wood is protected to a certain degree making it a lot more durable.

Fruit & Nut Farms

Poles are used mainly on Citrus farms and Macadamia farms. Fruit is generally covered with netting to protect it against weathering conditions and birds. Poles are needed to set up these nettings. The poles needed for this application should be CCA treated because the wood will be moist most of the time. If the wood is treated, it is protected and a lot more durable.

CCA Treated Timber is a long-term cost-effective method of protecting your trees without having to worry about the effects it will have on your ground, water and fruit trees. There is no bleeding, leaching, or evaporation of chemicals into the ground.

Jettys and walkways

Jetties are used to connect the land with deep water farther away from shore for the purposes of docking ships and unloading cargo. Jetties can also serve as a walkway into the water. Walkways allow you to reach certain hard-to get places.  Timber decking is normally used for a jetty or walkway, because of its low cost, relatively easy construction. It’s ideal because a wet walking area should be built with material that offer non-slip qualities.

Timber retaining walls

Retaining walls work well when you want to bring order and change to your landscape. It is often found in areas where extra support is needed to prevent soil from sliding all over the place such as backyards and garden areas. Generally if retaining walls will get exposed to moisture and this is why treated timber must be used.

Structure Piles

Timber piles are poles that are used to transfer extreme weight (gravity) either directly or indirectly to the earth. Foundations that are built high above ground are always strong enough to handle the weight; this is where timber piles are very effective. Piles are generally under foundations, where the grown is mostly moist. Timber piles make it possible to build timber structures in the most remote places. For instance, on dunes where concrete foundations are not permitted, timber will work well.


Hazard Class 5 CCA pressure treated poles with lengths of up to 3 meters are used for this application. There are two types of vine support structures namely vertical trellis and horizontal trellis.

  • With vertical trellis, two wires are used, the first one is a meter above ground and the second wire is placed another meter higher than the first one. This is for good ventilation between the vines. Poles are used as support structures to attach these wires to.
  • Three wires are used with the horizontal system. For trunk support, one wire attaches to the post about 1 meter above ground. By attaching two parallel wires horizontally to the ends of 1,2-meter long cross arms secured to poles 2 meters above ground, you hold the canes in place.

If you use timber that is not properly treated you can end up with vineyards literally falling apart because of termites and rot. That is why it is essential that you use the correct materials for setting up the structures for your vineyards.

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