Green Guide to Specification

The Green Guide is a tool for assessing some of the embodied impacts
of construction elements as part of an overall environmental or
sustainability assessment for a project or development. For some
projects, use of the Green Guide is effectively mandatory due to client
requirements or as a component part of a Code for Sustainable Homes
or BREEAM assessment.

The interdependence between operational and embodied impacts of construction materials will remain essential to sustainable design, and this requires them to be considered together. Good design will consider the A+ to E scores in conjunction with other information about the construction element and the overall design, such as air tightness, thermal bridging, thermal mass, overheating requirements, acoustics, and moisture control.

Part L of the Building Regulations is changing to accommodate new factors, including the thermal mass of a structure and its relationship to overheating and passive solar gains. Thermal mass is an important factor in the design of energy efficient low-carbon dwellings – the recognised benefits of thermal mass are currently not accounted for in the guide.

The concrete industry is well placed to demonstrate the highest level of responsible sourcing performance based on effective management systems, local availability of materials and well managed supply chains. Within the Code for Sustainable Homes, responsibly sourced materials are encouraged and credited, for both basic building elements and finishing elements.

Developing a sustainable design involves maximising the points scored in all the other parts of the sustainability assessment whilst optimising the score in the Materials section. Where a designer or client has chosen to use concrete products as part of their design solution they will find that there are many concrete construction elements in the Green Guide, many of which score well against the rating system of A+ to E. There are also sections of the guide where concrete scores extremely highly. For instance, in cavity walls for all building types it is quite easy to score an A or A+ rating. There are a number of design strategies that can be considered when selecting concrete elements, each of which can influence the overall rating positively. Examples of these strategies are:

• Optimising cementitious materials.

• Use of recycled or secondary aggregates.

• Optimising mass.

• Use of admixtures.

• Contacting suppliers for product specific information.