Wood: A cure for the world’s ills?

By Leon Louw

There are several reasons timber is becoming more popular in construction. However, using wood in any form, outdoors and indoors, requires a fair amount of maintenance and treatment, Frikkie Greeff, managing director of Woodoc, tells Timber iQ.

Many architects believe that timber is the building material of the future. With climate change and carbon emissions topping the agenda of most discussions about the future of humankind, timber provides a solution that is not only aesthetically appealing but also sustainable. Seen from a green angle, timber structures would allow us to draw carbon from the air and store it in our homes and offices.

One of the primary benefits of using timber, is that tons of concrete do not need to be poured into the ground as foundations. Timber buildings are a lot lighter than buildings made of bricks and mortar, which means the gravitational load is significantly reduced. If timber walls and timber floor slabs are installed, builders can also reduce the amount of steel used in the main internal support and in the reinforced concrete. Concrete is responsible for more than 8% of the world’s carbon dioxide (CO2) emissions.

But wood is not necessarily the magic cure for all the world’s ills. Concrete will continue to be used globally, even if it is on a reduced scale. The concrete- and cement sectors employ millions of people around the globe, something that the timber industry might not be able to do. There is also the ‘end of life’-question. Carbon only remains trapped in the wood for as long as the building remains standing or if the wood is reused. If the wood rots or burns away, all the stored carbon is released again. The aim should thus be to preserve, treat and maintain timber correctly, using the most effective materials to prevent its early demise.

Woodoc prevents the rot

According to Frikkie Greeff, managing director of Woodoc, it is essential that the most effective materials are used to treat wood products. The original Woodoc Sealers were formulated to penetrate and nourish the wood and enhance its texture and beauty. “It is especially important to treat wood in a country with a harsh climate like South Africa. The adverse effects of the climate, together with the deterioration of wood due to fungal and insect attack poses substantial challenges that can only be addressed with correct preservative- and protection treatment of wood,” says Greeff.

Wood is a living material. To preserve its natural beauty, it needs protection from the elements and the effects of time. The wood in living trees is protected by bark and nourished by natural sap. If these are taken away, the wood is left to the elements and will dry out and rot away. When trees are felled and turned into timber, the bark needs replacing to protect the wood and so does the natural sap that nourished it. Paint is one way to protect wood, but at the price of hiding its natural beauty.

To showcase the natural beauty of wood, transparent wood finishes are needed – wood finishes that last, protect the wood and enhance the lustre and grain by nourishing it. How soon the wood should be treated after felling depends on the type of treatment and the purpose of the wood.

Treating exterior and interior wood

Greeff says that if interior wood is treated with the correct product, and according to the manufacturer’s specifications, it should not be necessary to treat the wood again. He cautions, however, that a notable exception to this rule is a timber floor. “Depending on how often a floor is used and for what, and how well it is maintained, it may become necessary to sand and re-seal the floor,” he says.

Greeff advises that exterior wood should be maintained at least once a year to keep it in top form. “This is especially true for timber decks, as these are subject to deterioration both from the effects of the weather as well as from use,” he says.

An exterior sealer is formulated to be able to withstand extreme challenges like hot and cold weather, expansion and contraction, high- and low humidity and UV-radiation. Consequently, an exterior sealer must be formulated to be as flexible as possible and to remain flexible for as long as possible, it must be UV-stabilised and like Woodoc Sealers, it must be biodegradable to make maintenance as easy as possible.

Interior sealers are formulated to be able to cope with bumps, scratches and spills associated with an interior environment. Consequently, an interior sealer must dry quickly and hard. It need not be UV-stabilised nor be biodegradable. It has to, however, be resistant to water, alcohol, and acidic substances.

Deck Sealers take a middle course by having all the characteristics of an exterior sealer and as many of the characteristics of an interior sealer as possible. From the above it is clear that one should never apply an interior sealer on exterior wood, nor should an exterior sealer be applied to interior wood.

The importance of sealers

The importance of the correct sealers cannot be overemphasised. Sealers are made from resins derived from plant oils, like linseed or sunflower oil. Greeff warns that there could be products on the market that are not always the best option, although they might be more cost-effective. Products containing harmful chemicals should be avoided. The greatest culprits are heavy metals such as lead, copper and chrome, toxic substances, products containing carcinogens, products emitting toxic fumes (like formaldehyde) and especially N-Methyl-2-pyrrolidone (NMP).

To avoid these products, consumers should make informed choices and only purchase products from trusted manufacturers. “It is important to read the product label carefully to note any health- and safety warnings. Avoid products with little or no health- and safety information on the label. Do not be hesitant to contact the manufacturer to obtain information regarding the safety of the product and most importantly, if no information is forthcoming from the manufacturer or you cannot get hold of them, avoid their products like the plague,” Greeff advises.

South Africa does not have a specific standard for wood surface coatings. This means that the market can police itself; if a manufacturer’s products are not up to scratch, the product will disappear off the shelves. Therefore, it is so important to stick to a known and trusted brand.

By being able to penetrate wood, bind with it and build up on the surface, Woodoc Sealers create a microporous layer of sealed wood. The sealer is therefore part of the wood, can move with the wood and allows controlled moisture exchange with the environment.

A wood proponent

Greeff says that if a wooden item is treated correctly and cared for, it has the potential to become an heirloom and increase dramatically in value. “This is especially true of items made of scarce hardwood types. Woodoc is a proven market leader in the wood-coatings and -protection market and can be trusted to supply only the best products and after-sales service,” says Greeff.

Having lived in a timber-framed home for more than 27 years, Greeff is a proponent of timber houses and -buildings. “Timber is a wonderful medium for construction and in many ways superior to traditional brick-and-mortar,” says Greeff. But despite a growing number of people favouring timber above traditional brick-and-mortar around the world, South Africans have been hesitant to construct timber buildings, often citing safety and longevity as the major reasons why they will not live in a timber home. Greeff says there is an unfortunate knowledge gap about the use of timber for primary construction. “Building in brick and mortar was relatively affordable in the days of low labour costs. Moreover, South Africa is not blessed with an over-abundance of indigenous timber suitable for construction. Consequently, timber- and timber-frame construction never became the norm, resulting in a substantial lack of knowledge about the use of timber for primary construction,” he says, but adds that the timber and wood industry in South Africa has a bright future if managed properly. “This means that land owners must have security of tenure to develop their plantations to the fullest, timber millers must follow best practices with milling and treating and the industry must do what is necessary to promote the use of wood as a renewable resource, Greeff concludes.