"When you have this beautiful timber, you don't have to do anything to it."
If you read our first Journal post with Corr’s founder Adam Storey, you might have noticed Adam referencing the use of cross-laminated timber, CLT. Corr Cabins is the only cabin company in the UK that is building with home grown CLT – in our case, sustainably and locally sourced Sitka Spruce that’s grown and felled just 30 miles from our factory in Invergordon in the north of Scotland. The use of CLT lies at the centre of Corr’s commitment to sustainable building and design, and to using innovative products and techniques.
So what is it, and how is it made?
CLT is an engineered wood product that consists of layers of kiln-dried dimension lumber (usually three, five, seven or nine layers) where each layer is oriented at right angles to the previous layer, and then glued to form structural panels. Think of a Jenga tower with its perpendicular layers of blocks, and the stability of this structural approach – until you start removing blocks, of course.
By using this perpendicular arrangement, each panel delivers excellent structural rigidity in both directions. CLT also offers a significant benefit in terms of sustainability when compared with traditional building materials such as steel and concrete, being lighter, with a better strength to weight ratio, and with a much lower embodied carbon footprint. Also, unlike concrete and steel, timber is clearly a regenerative material.
“One of the key elements of using CLT is that it gives you the finish and the structure all wrapped into one,”
Explains Graham Currie, Corr’s Director of Architecture and Interiors.
“You’re building using natural materials that are also forming the structure, so quite quickly you have a weathertight box.”
This approach requires that every detail of the structure is designed up-front, with any openings – for doorways and windows - cut into the CLT slab before the cabin is constructed. Because each cabin is built in the factory, there’s minimal time on-site as the structure arrives completed, ready to be lifted onto its foundations.
“This means that you’re reducing on-site labour, and also the environmental impact of this as you don’t have a muddy or messy building site to manage,” - Graham says.
“There’s a lot of flexibility in terms of the foundations – a cabin can sit on low-impact Jackpad® foundation pads, or on screw piles, and this in turn impacts on the types of locations where cabins can be sited.
Quite often we find ourselves looking at sensitive woodland areas, and when you’re working around tree roots or protected trees you can’t use traditional concrete slab type foundations.
The lightweight nature of CLT enables us to work more sensitively within the landscape.”
Adam and Graham had been discussing the use of mass timber for some time.
“From a sustainable perspective, we didn’t want to import materials, especially timber. When we came across the team at Ecosystems in Invergordon, we realised that we shared the same ethos and values.” - Graham reflects.
By using CLT as an internal finish, each cabin feels connected to its natural setting, both outside and in.
“You have to be inside a cabin to fully appreciate the benefits of this material, but imagine having 100mm of natural timber around you. It’s a dense product, which offers a fantastic acoustic quality as it absorbs sound, and when you touch the surface, it feels warm and substantial.
When you have this beautiful timber, you don’t have to do anything to it. Most of the cabins are centred around a picture window, so you’re looking out towards a natural environment while being within a natural environment. People really enjoy this aesthetic.”
