How is the sustainability of a house rated under the Code for Sustainable Homes?
The sustainability rating of a home represents its overall performance across the nine code design categories.
Minimum standards exist for a number of categories. These must be achieved to gain a one star(*) sustainability rating. Energy efficiency and water efficiency categories also have minimum standards that must be achieved at every level of the code, recognising their importance to the sustainability of any home. Apart from these minimum requirements, the Code for Sustainable Homes is completely flexible; developers can choose which and how many standards they implement to obtain credits under the Code in order to achieve a higher sustainability rating.
The Code for Sustainable Homes uses a sustainability rating system indicated by stars to communicate the overall sustainability performance of a home. A home can achieve a sustainability rating from one (*) to six (******) stars depending on the extent to which it has achieved Code standards. One star (*) is the entry level above the level of the Building Regulations; and six stars(******) is the highest level reflecting exemplar development in sustainability terms.
What are the key issues in the Category 3 – Materials element of the CSH?
The aim of this design element is to encourage the use of materials with a lower environmental impact spread over the lifecycle of the building.
Credits are awarded where an assessment is made of the number of credits awarded in at least three of the five key elements which achieve a relevant BRE Green Guide rating of A+ to E (roof; external walls; internal walls; upper and ground floors and windows). Between 1 and 15 credits can be achieved, depending on the Green Guide rating – the higher the rating the lowest overall environmental impact.
This category also recognises and encourages the specification of responsibly sourced materials for the basic building elements. Points are awarded where materials are used in the key building elements below. They represent 80% of the total assessed materials. Credits are also awarded for responsibly sourced materials used in the finishing elements of the building.
What are the maximum points available for the roofing and wall elements within the CSH?
The total number of points available for the Materials category is 24 which accounts for 7.20% weighting of the maximum number of credits available. The Environmental Impact of Materials accounts for a maximum of 15 points with Responsible Sourcing of Materials – (basic building elements). Using the generic 'Green Guide' A+ rating for concrete tiles and clay tiles, a maximum of 3 credits is achievable for a conventional pitched roof, using 100mm mineral wool between joists with a further 200mm over joists. Choosing products which achieve a lower rating, will reduce the credits awarded A+ = 3 points; A rating = 2 points; B rating =1 point; C, D or E = 0 points.
Our range of concrete and clay tiles achieve an A+ rating in the BRE ‘Green Guide’, and as such provide the maximum number of credits available for the roof and walls when using the calculation methodology in the CSH. In addition, all of our UK manufactured clay and concrete roofing products are assessed under BES 6001 responsible sourcing and qualify for an additional 2 points.