To celebrate this anniversary, we’ve taken a look at how to treat timber for architectural façades.
In 2022, Maple installed over 12 miles of timber fins onto the car park at The Christie Hospital in Manchester. The project was a great achievement for Maple, as Peter Dodd, Senior Project Manager for VINCI Construction UK, recognised its success in bringing the architect’s vision to reality, meeting an “accelerated programme, and delivering a quality product.”
Before installation began, Maple had to ensure the timber was a suitable façade option. Without treatment, timber would not have the longevity needed for an architectural façade and is naturally combustible therefore contrary to fire regulations.
Timber is a worthwhile consideration for modern architectural façades as it satisfies both aesthetic and sustainable objectives. However, the reality of specifying timber can lead to some costly additions, such as stronger fixings and treatments.
HOW TO TREAT TIMBER FOR ARCHITECTURAL FAçADES?
Without the required weather treatment, timber façades will deteriorate quicker due to exposure to external elements, resulting in frequent repairs. Timber is a natural resource which is a plus in terms of sustainability but a potential con in terms of maintenance. Façade upkeep is inevitable, but treating timber can help reduce the amount of repairs needed.
In the case of The Christie’s timber façade, Maple chose brunnea-treated timber to ensure the longevity of the façade. Brunnea treatment is a process that involves impregnating the wood with a mixture of brunnea and a water-based preservative to protect it against insects, rot and fungal decay.
Also, brunnea inhibits UV rays and prevents the timber from losing its natural colour over time.
Fire retardancy is also a vital consideration when treating timber. Although timber will never reach an A1 fire rating, it is possible to achieve Class B by using a fire retardant. The process involves impregnating wood with a fire-retardant chemical before installation in a controlled, factory environment. It works by preventing oxygen from reaching the timber thereby slowing the rate of ignition and fire spread. In compliance with fire regulations, treated timber must be tested to meet Euro Class B or Class C in line with EN 13501-01 standards.
Overall, a timber façade is a great option for a natural, rustic aesthetic and demonstrates a commitment to sustainability by using natural resources. On the other hand, many variables (cost, weatherability and fire regulations) must be considered during specification to achieve a long-lasting, impressive façade that adheres to Building Safety Regulations.