WHILE timber construction has a relatively small footprint in South Africa, the building material is enjoying increasing popularity and interest among the general public and trade alike. Even so, misconceptions about timber as a construction material are still commonplace, limiting potential users from enjoying the manifold benefits of this unique, renewable building material.
That’s according to Dr Brand Wessels, Chairperson of the Department of Forest and Wood Science at the University of Stellenbosch, who said the three most common myths that circulate among the general public and even the professional trade about timber as a building material are that using trees to manufacture products is not environmentally responsible; that wood structures are not as structurally safe and durable as steel or brick and mortar structures; and that wood structures are an obvious fire hazard.
Plantations, not natural forests
On the notion that using trees to manufacture products is environmentally irresponsible, Wessels said there was a distinct difference between harvesting timber from sustainable and well-managed plantations and the deforestation and degradation of natural forests that should be protected.
“In South Africa, we use timber grown in responsibly managed plantations, which are like working factories with the sole purpose of growing timber in a controlled environment for the market. Managed by reputable bodies like the Forest Stewardship Council (FSC), these plantations are operated in line with the highest standards for ensuring sustainability.”
He cited recent studies, including one carried out in South Africa, which show that tree planting and forest restoration are the most cost-effective strategies with the greatest potential of combatting global climate change.
Strength and durability
Contrary to the misconception that timber structures are not structurally safe and durable, timber has a higher strength-to-weight ratio than either steel or brick and mortar, said Wessels.
“This misconception may be linked to perceptions around low-cost, poorly built informal housing of wood. On the contrary, in some applications, such as for housing in earthquake-prone areas, wood is preferred above other materials. There are structures that are 1200 years old in Japan (an earthquake-prone country), which attest to the material’s durability and strength.
“As with any other material, a well-designed and built wood structure will last a lifetime; conversely, a poorly designed and built structure – of any material – will not endure.”
According to Amanda Obbes, General Manager of the Institute for Timber Construction South Africa (ITC-SA), timber frame construction is a standard construction methodology under the National Building Regulations (NBR), which provide the necessary building codes for the manufacture and construction of safe, legal and durable structures that are built to standard.
Timber under fire conditions
According to the ITC-SA, structural timber for roofing is both commonplace and performs well under fire conditions.
As with every aspect of building, timber roof trusses must be manufactured and erected in line with the National Building Regulations and SANS 10400, which provide for fire safety. Building regulations, set in place by bodies such as the South African Bureau of Standards (SABS) after extensive research and consultation with industry experts, consider all aspects of a given building material’s composition and properties to ensure that it meets the same safety and performance standard as any other building material in the same application.