Square wood poles, also known as a square beam, are exactly what the name says, a round gum pole that has been cut into a square. But there is a lot more to Square wood poles than you might think. In this article, we will share a few interesting facts about square wood poles that will let you realize the value of this timber product.
The process from harvesting to the final product
The process from choosing the correct trees to cutting the pole into the correct size takes up much patience and precision.
Harvesting the Eucalyptus tree
Bigger trees are needed for square wood poles, e.g., for a 180mm x 180mm square wood pole, a tree of at least 350mm in diameter is needed (to achieve the correct square wood pole size, a tree of at least 100 times the size, is needed).
The challenge to this is that it takes up to 30 years for a Eucalyptus gum tree to reach that size. This means that stock is handled carefully. At Sabie Poles, we only cut these trees upon request for square wood poles to ensure that we do not run out of stock.
When trees are harvested for our general timber products, we leave certain trees behind allowing them to keep on growing to their most mature size.
Cutting the wood
The wood is cut into certain lengths and thicknesses in the plantation and then transported to the treatment site for further cutting. The wood must be cut into longer lengths than the required order, e.g., if there is an order for 5m square wood poles, the wood needs to be cut into 6m lengths at the plantation site. This is called an overcut.
Upon arrival at the treatment site, the wood is offloaded. With the use of a proper bandsaw, the sides are cut off to form the perfect required square. It is important to know that the wood needs to be cut while it is still slightly wet. This makes it easier for the machines to cut the wood.
The Square wood Poles are then air stacked to dry naturally. When the square wood pole reaches its desired moisture content the poles are cut back into the desired lengths The whole process, from harvesting the tree to preparing the poles for treatment, takes up to ten working days. This is why we give our clients 14 working days waiting period before receiving their timber product.
The use of cut-off slats
Little to no timber is ever wasted at Sabie Poles. The sides that are cut off to form the square, which we call slats, will be used for other timber products. This is also a process that takes some time and patience. The wood is air-stacked to dry for up to a year before it will be recut into saligna planks. The saligna planks are moulded into timber mouldings such as decking and flooring. Before the slats are cut, their moisture content has to be under 5%. The reason for this is so that the mouldings do not crack when installed.
How square wood poles are CCA treated
We treat all our timber because we know the importance of our treatment. We believe in top quality and durability when it comes to our timber products. Square wood poles may not use as many chemicals as our other timber products, but we still feel that it needs to be treated. When the sides are cut off to form a square, most of the sapwood is removed (the CCA chemicals are generally penetrated into the sapwood) and mainly the core wood is left behind. The core wood has no air pockets or cell chambers making it impossible to penetrate the chemicals through the wood. However, as mentioned, there may still be some sapwood left behind. we take that advantage by still treating these poles poles.
The square wood poles are added to other poles with more or less the same diameter with a treatment charge. Due to the fact that only the leftover sapwood is treated we speak of an “Envelope treatment”.
When most of the sapwood of the pole is cut off, a solid block of wood (the core wood) is left behind. There are no air pockets or cell chambers. This alone is an indication that the pole is strong and durable.
Sometime after treatment, natural surface cracking may form. This is nothing to be concerned about as it does not affect the strength and durability of the square wood pole.
These poles should not be in ground contact and can only be used for under-roof purposes. Below is an image that indicates the correct way of installing a square wood pole.
Make sure poles are strapped at the ends with stainless steel strapping, especially when anti-split end plates are sawn off. Take into consideration that when a CCA-treated product is cut after treatment the chemical guarantee expires. Should you decide to saw the pole after treatment, make sure to seal your sawn wood with Tanalised Enseal Green. We have this product available for sale at Sabie Poles.
The role of square wood poles
Places such as SPA’s and lodges make use of square wood poles in the construction of their buildings. This because of their authentic natural style, it adds a more natural feel to a building. They are brilliant for creating stunningly designed ceilings (in double storeys) patios, partitions, and outdoor bomas.
Two main applications square wood poles are used for:
Beams – Beams are mainly used in roof structures, it acts as a support structure to the whole roof. There are various kinds of beams that are important to know when requesting a quote:
- Simple support beam: this beam is simply supported on both of its ends.
- Continuous beam: It is similar to a simple support beam, however, one end has hinged support, while the other end has multiple roller support structures.
- Cantilever beam: This wooden beam is only fixed on one end, while the other end is free hanging.
- Fixed beam: Fixed beams are simply fixed in place on both ends.
A rafter extends from the roof ridge to the top plate of the exterior wall. Sometimes the architectural design requires the rafters to extend past the top plate of the wall. This is called an overhang. Rafters can be used as a base for attaching a roof cover. They support most of the weight of a roof.
Our square wood poles are extremely strong and durable. There are many ways these poles can be used in small and large construction projects. We wrote an article on the uses of square wood poles please read it by clicking on this link: Square wood poles for construction
Square wood poles available at Sabie Poles
Our square wood poles are made from Eucalyptus trees. We offer the following diameter classes – 60mm/60mm, 80mm/80mm, 100mmx100mm, 120mmx120mm, 140mmx140mm, 160mmx160mm, 180mmx180mm and 200mm/200mm. We can also custom cut the log to your desired dimensions. The maximum length we have available is 6.6m.