Putting it into practice

The waste hierarchy below shows the process that should be considered when looking at the use of materials both during construction and during the operation of a building:

Figure 1: Hierarchy of materials

The design of new developments and refurbished buildings can be carefully considered to use materials and resources as close to the top of the hierarchy as possible. We have considered the prevention and minimisation of energy in the earlier sections, but re-use and recycling can play an important role in improving the sustainable performance of property:

Grey water and water recycling:

• grey water is usually defined as rainwater that is harvested for use for flushing of toilets and landscape irrigation;
• toilet flushing typically uses 33% of water use in buildings;
• grey water from dishwashers, sinks and showers can be used for landscaped irrigation - some plants love the extra nutrients;
• use of grey water involves less energy to clean and pump the water and less chemical use;
• grey water from sinks, showers, etc. needs to be chemically or microbiologically treated and should have minimal storage to prevent microbe build-up;
• in trials by the Environment Agency, water savings of between 5% and 36% were achieved by using grey water.

Reclaimed construction materials:

• aggregates make up >50% by weight of all construction materials;
• in the last years, natural forest cover has been reduced by 11%;
• the use of reclaimed construction materials is far better than recycling, which itself is far better than disposing of old materials and sourcing virgin materials;
• current reclamation rates are typically 1% but it is estimated this could be between 5-10% with better waste management;
• the introduction of Site Waste Management Plans as a requirement for projects greater than £300,000 has really focused contractors’ processes in particular, as has the cost of sending material to landfill or waste processing;
• consider the source of the material - local sources means fewer vehicle movements to site;
• better waste management on site can reduce waste from 6% down to 0.5% - use segregated bins, ensure correct training of operatives and subcontractors, off-site manufacture also reduces waste;
• for example, reclaimed steel reduces the environmental impact compared to new steel (which typically has 40% recycled content) by 96% - a huge difference.

Typical reclaimed materials that can be used:

• reused timber sections of floorboards;
• bricks that are cleaned up and reused;
• steel sections can be shot blasted and refabricated;
• glass panels or windows can be reused.

Typical products that can be recycled:

• panel products can be bought that contain chipped recycled timber;
• crushed concrete or bricks can be reused for hardcore;
• steel with a higher proportion of recycled content may be available;
• asphalt can be reused as a road surface topping;
• recycled aggregate can be used for concrete - however, careful control is needed;
• newspaper, textiles and wool can be used for insulation;
• carpets can be made of recycled yarn - e.g. Interface's Transformation range of carpets.

Most construction sites should be able to achieve 95% recycling rates for their waste material produced.

Other materials with sustainable qualities include:

• Bubbledeck - a proprietary lightweight concrete containing plastic balls between a top and bottom layer of mesh, uses only 50% of the concrete used in a traditional form of construction;
• crushed glass can be used for the bedding of paving slabs, etc. instead of sand;
• a green roof - green roofs, such as 'Sedum', allow grass and other vegetation to grow on the roof providing a better aesthetic appearance and can have insulating properties.