When undertaking a house build project, there are lots of ways to dress up the exterior of your home. Particularly popular in rural builds, timber cladding is a clever way to help a home to blend into the landscape. However, when cladding is part of the design, then comes a sometimes overwhelming choice: what sort of cladding should I use? Timber is a renewable resource, but is it the most sustainable? The most practical?
Sustainable cladding refers to the use of environmentally friendly materials and practices in the construction of building facades. This approach aims to reduce the negative impact on the environment by using materials that are renewable, recyclable, and have a low carbon footprint. One example of sustainable cladding is timber sourced from responsibly managed forests.
Timber cladding in the UK has traditionally been sourced from Larch or Cedar. The best Larch comes from Siberia, and the best Cedar comes from Canada. A number of factors in recent years mean timber supplies and prices have been unpredictable. As well, many consumers have turned away from using Siberian Larch, out of a desire to boycott Russian products in the wake of Russia’s invasion of Ukraine. The carbon footprint associated with shipping timber from Russia or Canada to the UK must also be considered when evaluating these options.
British timber, either Larch or Cedar, tends to be of a lower grade than Russian and Canadian alternatives, requiring additional treatment in order to achieve the durability our British climate requires. It seemed to me a strange compromise to trade fewer miles in shipping for more heavy chemical treatment. I did start to wonder if I was robbing Peter to pay Paul, as they say.
When I investigated alternatives to cedar and larch, Thermowood kept coming up as a possible alternative. Our main contractor has warned us, however, that it can be quite brittle as a result of natural oils and moisture being removed from the wood during the heat treatment. This leaves it vulnerable and often means that a larger percentage of the wood becomes unusable at the point of installation. Accoya is another type of treated wood that is known for its high durability.
Accoya is virtually impervious to water, but comes at a very high cost: typically between three and five times higher than traditional timber cladding. That being said, if you can afford it, Accoya have achieved “Gold” status from Cradle to Cradle, and offer a lot of great tools for calculating and reducing your environmental impact, which you can see here.
Another alternative which I had previously discounted is composite cladding. At first I didn’t like the idea of cladding our house in plastic. However, the options available today can be quite good looking and environmentally responsible. Composite also tends to have a longer life than real wood.
Millboard, Envirobuild and Ecoscape, for example, offer composite cladding made with up to 95% recycled plastics. I ordered samples from all three, and I personally found Millboard to be the most aesthetically pleasing. It looks the most realistic of the three. Specifically, we selected the Envello Board and Batten in Burnt Cedar. It looks more like real wood than either Envirobuild’s Hyperion product range or Ecoscape’s slatted cladding. That aesthetic comes for a price, though, as Millboard is more expensive than Accoya.
Millboard cladding is made from a combination of recycled plastic (over 33%), biopolymers (a fancy way of saying plastic made from vegetable oil instead of petroleum oils), and traditional plastic raw materials. Their packaging is fully recyclable and all paper and cardboard materials they use are FSC Certified. They are also Carbon Reduce Certified (by my previous employer, Achilles! I didn’t even know that until I saw it on the website after ordering samples from them – promise!), which means they are on a journey to track and reduce carbon emissions. Their carbon reduction journey has been independently certified by an independent third party: Toitu Envirocare. Their products are manufactured in the UK, reducing shipping miles.
So, while I prefer to use natural materials, composite cladding from recycled materials could, on balance, provide the right alternative to timber that would have to be shipped in from a great distance, be heavily treated, or may not provide a durable exterior building material.