The main idea of using sustainable building materials is to construct a property which has longevity, resulting in lower maintenance costs and fewer annual up-keep issues.
But what does “sustainable” really mean? Well, it’s generally accepted that sustainable means using materials which are plentiful in supply or adopting methods which do not completely use up or destroy natural resources. As a result, the finished product is able to last for a very long time. A key tenet of sustainability, therefore, is to use material where the supply can be replenished and ensure that scarce resources last for future generations.
Sustainability, in the context of designing and planning buildings, is quantified in terms of various measures of environmental, social and economic performance. In the UK, offices and public buildings are assessed using BREEAM, and housing and residential buildings are assessed according to the Government’s Code for Sustainable Homes. Similar sustainability assessment procedures exist in other countries, such as Leadership in Energy and Environmental Design (“LEED”) in the USA.
So, whilst cost reductions and extended life-spans are strong enough reasons to convince anyone building property to make it a sustainable home, what sort of materials should be used to make a sustainable property last so long and make it cost-efficient?
It may not be well-known but steel is one of the most environmentally friendly materials for use in building and fabrication processes.
Steel is an alloy made from iron with typically a small percentage of carbon added to improve its strength and fracture resistance compared to other forms of iron. One of the key advantages to using steel over wood or other materials is its durability. Steel is much stronger than wood products and is not susceptible to termites and other pests or even decomposition or rot as the material ages.
Light steel, sometimes known as cold-formed steel or cold-rolled steel, is a material which is used to make construction processes smoother and products stronger. It is not bulky, like structural steel nor heavy like concrete.
Light steel framing comprises galvanised cold-formed C sections, typically, of 70mm to 100mm depth for wall panels, and 150mm to 300mm deep C sections or lattice joists in floors. Spans of up to 6m can be achieved, which can eliminate internal load-bearing walls and therefore allows flexibility in internal space planning.
The sustainability benefits of light steel framing and modular construction are based on the off-site nature of the construction process, plus the fact that the embodied carbon in the building fabric is reduced by up to 20% when light steel framing and modular construction is used.
Some sustainability benefits of light steel framing and modular construction
Such benefits include:
- Embodied carbon in the building fabric is reduced by up to 20% when using light steel framing and modular construction.
- High levels of thermal insulation and air-tightness are achieved.
- The light weight of such construction systems means that foundation loads and sizes are reduced by over 70% relative to concrete and block-work construction.
- Light steel structures can be modified and extended easily and modular units can be dis-assembled and re-used; long spans and large openings can be created.
- Light steel is ideal for building extensions and in renovations, due to its light weight and speed of installation.
- Generally, productivity and speed of construction is increased by over 30%, which reduces the impact of site works.
- Transportation needs are greatly reduced; for example, a single delivery of light steel is usually sufficient to build three houses.
- Site safety is improved by a factor of five or more according to HSE statistics due to the off-site construction process.
- Site waste is virtually eliminated by the use of pre-fabricated light steel and modular components compared to the industry average wastage rate of some 10% in construction materials.
- Use of components rolled to length results in no production waste.
- Renewable energy technologies can be attached to and built-in the light steel and modular components.
Some applications of light steel framing
Light steel framing and modular construction are used for housing, residential buildings, educational and health sector buildings where achieving high levels of sustainability according to the Code for Sustainable Homes and BREEAM is important. They may also be used in renovations, such as roof-top or other extensions to buildings.
The benefits of light steel construction in relation to residential buildings are speed of construction (up to 40% faster than traditional methods) and excellent performance characteristics e.g. fire resistance, acoustic insulation, and thermal insulation.
There is also a high level of quality control, accuracy and freedom from shrinkage, reducing call-backs for defects, as well as waste recycling in manufacture and reduction of on-site waste.