We rounded a corner of the Ligna Group factory and there it was. Our order of Timbercrete (Ligna Stone) blocks was sitting on pallets, waiting for delivery. We could actually see and touch one of the key materials going into our home after talking about the possibility for nearly three years.
What is Timbercrete?
Timbercrete is an Australian invention which is a sustainable alternative to the bricks traditionally used in building homes.
The main ingredient is sawdust or wood waste from a timber mill. This byproduct of a sustainably managed tree plantation is not burned or allowed to decompose. Instead, the carbon in the wood is locked up for many years inside a Timbercrete block.
Wood waste is combined with sand and special binders to make a slurry. Once all the ingredients are completely mixed, the slurry is poured into moulds. After a few hours of air drying, the blocks are stacked and allowed to cure outdoors. Three months later, the blocks are ready to use in construction.
Why did we choose Timbercrete?
We selected Timbercrete from the Ligna Group instead of standard bricks for several reasons.
A building material made from a renewable resource (mostly) fits nicely into our sustainable design philosophy.
Making Timbercrete blocks consumes much less energy than kiln firing clay bricks. Energy from the sun is all that’s needed to complete the manufacturing process. Local production also helps to reduce the carbon footprint. The Ligna Group factory is only a couple of suburbs away so the transport distance is quite short.
Good thermal performance is a useful feature. These blocks add thermal mass to our home as well as providing another layer of insulation. Tests show that Timbercrete has a higher specific heat than other construction materials. On a sunny day in winter, the blocks absorb more energy than concrete (per kilogram) to raise their temperature by one degree. The energy in the walls is released at night to help keep rooms warm. In summer, the specific heat works in our favour to reduce the chance of a room getting uncomfortably warm. The blocks are slow to increase in temperature as they absorb heat caused by activities inside the well-insulated family room.
Using a reverse-brick veneer construction method of our homes means we take advantage of these thermal properties. A thick layer of insulation between the blocks and external cladding stops heat going in or out. On a cold winter’s night, heat from inside can’t get out. During one of those 40+ degree scorchers in summer, heat can’t easily find its way inside.
We like the appearance.
We also like the look of Timbercrete blocks. They have an earthy, natural look and colour. From a distance, they are reminiscent of sandstone blocks. However, up close, you can see small flecks of wood in the surface so there is a clear connection to something made from natural materials. The reverse brick veneer means the blocks are a feature in the kitchen and family room. They’re too attractive to hide!
Building with Timbercrete blocks.
Much as we’d like it to be, Timbercrete isn’t a product commonly used by brickies in Melbourne.
Fortunately, David found a firm that met all our requirements for doing this work. Melbourne Brick and Block have the required skills and experience working with Timbercrete blocks. They are also interested in what we’re doing and keen to participate in a sustainable home build.
In late-April, the blocks will arrive on site. Then it’s over to Melbourne Brick and Block to do their thing and construct the walls. We can’t wait to see the result.