Sustainable construction materials are a critical factor in reducing the amount of waste and pollution we create. A recent report by the United Nations found that the construction industry accounts for 38% of energy-related C02 emissions. By switching to sustainable building materials that release less carbon, we can save significant amounts of pollution.
What Are Sustainable Materials?
Sustainable materials are made from renewable raw resources, produce little waste during production, can be recycled, and help create an efficient home. Other important factors include the lifespan and durability of the material and shipping distance; imported products have lower sustainability due to pollution created during transportation.
There is no one set definition or award that states a building material is sustainable, and in many cases, you may need to weigh up contrasting factors. For example, if a material creates pollution when it is manufactured but then saves significant energy during its lifetime and can then be recycled, is it sustainable? Examples of sustainable materials include rammed earth, straw bales, bamboo, slate roof tiles, and wool insulation.
Below, we’ve provided an overview of sustainable options for construction, roofing, flooring, insulation, and more.
Sustainable Building Materials for Eco-Friendly Homes
Sustainable building materials such as rammed earth, straw bales, structural insulation panels (or SIPS), and mass timber enable home builders to create an energy-efficient home from eco-friendly materials that are durable, renewable, and can be recyclable or biodegradable once they reach the end of their useful life.
Below, we’ve looked at eight materials you might want to consider when planning the construction of your home. This section just concerns materials used for the walls of your home – there are separate sections below for insulation, roofing, and flooring.
Rammed earth construction is a traditional form of construction that involves filling a framework with earth and/or aggregates such as sand, gravel, and clay, and then ‘ramming’ them down with a wooden pole or pneumatic ram before moving the framework. Some modern rammed earth structures add 5-10% cement to increase stability.
Rammed earth construction is very eco-friendly: the materials it uses are plentiful and they can be reused if the structure is demolished. While its distinct appearance is popular with some, it isn’t for everyone. Rammed earth does not insulate well, so outer walls require additional insulation, and there are some concerns over the long-term durability of structures made using this method.
Straw bale construction is a sustainable building technique that produces thick, airtight walls with a high thermal mass for a low cost. Straw bale buildings stay cool in summer, retain heat in winter, and are at no greater risk of fire than other types of building. Straw bales are easy to work with and can be carved using a chainsaw, allowing the creation of curved walls and other pleasing designs.
Straw bales are extremely eco-friendly – they use an easily obtainable waste product that will biodegrade if the building is demolished. However, straw bale construction does have a few downsides: the thickness of the walls restricts the available square-footage of the building and they must be protected from damp both during and after construction. Excess moisture leads to rotting and expansion, which can allow mold to infiltrate the walls.
Clay bricks are durable, recyclable, and made from an abundant material. As a construction material, bricks are strong, low maintenance, and a good insulator for both heat and noise. They can also be used in a wide variety of styles and are fire-resistant.
Bricks are sometimes described as an eco-friendly construction material, but this depends on how the clay is baked (many kilns use natural gas to heat them) and whether the mining of the clay is good or bad for the environment. Recycled bricks are a good option for an eco-conscious builder, or there are some companies that produce green bricks from recycled products and/or using eco-friendly baking processes.
Bamboo is a fast-growing and sustainable grass that can be used to create construction materials. It is strong, durable, and abundant, and is commonly used in both Asia and the Americas, although the wetter, colder climate in Europe make it less suitable for use there.
Bamboo is considered highly eco-friendly. Not only can it absorb a lot of greenhouse gases, but compared to trees it can grow back incredibly quickly, and can often be harvested every few years (annually for some types). In comparison, a hardwood planation might only be harvested once every 50 years.
Structural Insulation Panels (SIPS)
SIPs, or Structural Insulation Panels, are pre-built storey-high insulated panels made from two sheets of either oriented strand boards (OSB) or cement particle board (CPB) with a layer of insulation between them. They enable builders to maximize room space, build quickly, and create a highly efficient, highly insulated building.
SIPs are considered an eco-conscious choice because they can be used to create highly-insulated homes which improve energy conservation and reduce energy bills. Additionally, the manufacturing process used to create them is nearly waste-free as they are made to size for each project. This does, however, mean that the design of the home must be locked-in before production begins.
Mass timber is a general term for a range of building materials created from engineered wood. Multiple layers or pieces of wood are stuck together to create load-bearing panels, columns, or beams that can be used instead of steel or concrete. The most common type of mass timber is CLT, or cross-laminated timber, but there are many other types including laminated veneer lumber (LVL) and glue-laminated beams (glulam).
Mass timber has plenty of benefits as a building material. It can compete with steel and concrete in terms of strength, is quick and easy to build with, and is considerably better for the environment. Where steel and concrete production adds C02 to the atmosphere, mass timber actually reduces it. All that wood sucks up carbon and keeps it there for the lifetime of the building. There has been considerable interest in mass timber, and successful projects such as the 18-storey Mjøstårnet have received considerable press-time.
Recycled Shipping Containers
Recycled shipping contains can be upcycled into a modular building material that can be used to create anything from single rooms to large buildings. They are tough, stackable, quick to build with, and affordable, and can make a great alternative to traditional building materials like concrete.
Bark, typically discarded as a waste product, is a sustainable cladding solution. It looks great, has a low impact, and requires no chemicals to create. It is also durable and requires no maintenance. The main downside of bark siding is that it isn’t the cheapest solution, something that holds it back from widespread use.