Sustainable Timber Pressure Treatments

The need to preserve

Wood is a versatile and beautiful material that has been used for centuries in construction, furniture-making, and other applications. However, wood is also susceptible to decay, rot and insect damage, which can shorten its lifespan and reduce its usefulness.

The accepted thinking is that softwood doesn't last when left outdoors, and that hardwoods should be used in places where durability is key. The shear expense of hardwood has meant that alternative ways to preserve timber have been explored for hundreds of years. 

In the early days, timber was treated with natural substances such as creosote, which is derived from coal tar, to make it more resistant to decay and insects. 

However, as time went on, it became clear that natural substances were not enough to protect the wood from the elements. In the 1930s, researchers began to experiment with chemical treatments for timber, which led to the development of the first synthetic preservatives.

Early adoption of this method was widespread and it was seen as a revolution in sectors such as construction, where huge quantities of softwood are used. However, primarily driven by cost savings, the environmental impact of this early technology was never considered to the extent that it has more recently.

The chemicals used in traditional pressure treated timber can pose risks to human health, not just to the environment. In this blog, we will explore environmentally safe pressure treated timber and why it is an important option for today's construction and outdoor furniture needs.

The Risks of Traditional Pressure Treated Timber

Traditional pressure treated timber is treated with chemicals such as chromated copper arsenate (CCA), pentachlorophenol (PCP), and creosote. These chemicals are effective at preventing decay and insect damage, but they also pose significant risks to human health and the environment.

The chemicals in traditional pressure treated timber can leach into the soil and groundwater, contaminating drinking water supplies and harming plants and animals. They can also release toxic fumes when burned, posing risks to air quality and human health. In addition, people who work with or come into contact with pressure treated timber, such as construction workers and homeowners, may be exposed to the chemicals through skin contact or inhalation.

Exposure to these chemicals has been linked to a variety of health problems, including cancer, respiratory issues, and skin irritation. Children are particularly vulnerable to the risks of traditional pressure treated timber, as they may be more likely to play on or around outdoor furniture made from this material.

Fortunately, there are now alternatives to traditional pressure treated timber that are safer for human health and the environment.

Change in UK Law

The UK has a long history of using pressure treated timber in construction and outdoor furniture. However, as the risks associated with traditional pressure treated timber became better understood, the government took action to ensure that these products were safe for human health and the environment.

In the UK, the use of chromated copper arsenate (CCA), one of the most common chemical treatments for pressure treated timber, was phased out in 2004 due to concerns over its toxicity. The use of pentachlorophenol (PCP), another commonly used chemical, was also restricted in the 1980s due to concerns over its toxicity.

In 2012, the UK government introduced new regulations to govern the use of pressure treated timber. These regulations, known as the Timber and Timber Products (Placing on the Market) Regulations 2013, require that all pressure treated timber sold in the UK meets certain safety standards.

Under these regulations, pressure treated timber must be treated with preservatives that have been approved. These preservatives must be safe for human health and the environment, and they must be used in accordance with strict guidelines to ensure that they are effective and do not pose a risk to human health or the environment.

In addition, pressure treated timber must be labelled to indicate the level of protection it provides against decay and insects. This information is important for consumers, as it allows them to make informed decisions about the safety and durability of the products they are purchasing.

Overall, the UK government has taken significant steps to ensure that pressure treated timber sold in the country is safe for human health and the environment. By regulating the use of preservatives and requiring clear labelling, the government is helping to protect consumers and the environment from the risks associated with traditional pressure treated timber.

Environmentally Safe Alternatives to Traditional Pressure Treated Timber

One alternative to traditional pressure treated timber is acetylated wood. This type of timber is treated with acetic anhydride, which changes the chemical structure of the wood and makes it more resistant to moisture and decay. Acetylated wood is non-toxic and has been shown to have a longer lifespan than traditional pressure treated timber.

Acetylated wood is created by chemically modifying the wood with acetic anhydride. This process changes the chemical structure of the wood, making it less susceptible to water absorption and decay. The process also increases the wood's hardness and stability, making it more resistant to warping and shrinking. Acetylated wood can be used in a variety of applications, including decking, cladding, and outdoor furniture.

Another environmentally safe option is thermally modified wood. This process involves heating the wood to high temperatures, which changes its chemical composition and makes it more resistant to decay and insects. Thermally modified wood is also non-toxic and has a longer lifespan than traditional pressure treated timber.

Thermal modification involves heating the wood to temperatures between 150°C and 240°C in the absence of oxygen. This process changes the chemical composition of the wood, reducing its moisture content and making it more resistant to decay, insects, and warping. Thermal modification can be used on a variety of wood species, including pine, spruce, and ash. The resulting wood is darker in colour than untreated wood and has a more consistent appearance.