• Green Guide 2008 ratings

    Green Guide 2008 ratings

    Building type >
    Category >
    Roof Construction


    Separate Roofing ratings are the provided for the following building types:
    Domestic, Education, Commercial and Industrial, Health and Retail

    Functional unit for Roofs for Commercial/Industrial:
    1m² of roof area, (measured horizontally), to satisfy building regulations and a U value of 0.16 W/m²K (pitched) or 0.25 W/m²K (flat). Based on an overall span of 15m with support at 7.5m.

    Variation for Education
    As for commercial buildings and based on a span of 15m with supports at a central corridor.

    Variation for Retail/Health
    As for commercial buildings with a span of 8m.

    Functional unit for Roofs for Domestic:
    1m² of roof area (measured horizontally), to satisfy England & Wales Building Regulations, particularly a U value of 0.16 W/m²K (pitched) or 0.25 W/m²K (flat). Span of 8m to include a plasterboard ceiling and emulsion paint finish.

    For commercial building of a domestic scale, i.e. 1-3 storeys, 8m roof span; the Retail/Health ratings should be used.


    A roof has greater impact for low rise buildings in comparison to high rise buildings. This is as would be expected as the roof area would be equivalent to 33% of the floor area for a 3-storey building and only 5% of the floor area for a 20-storey building.

    Roofing specifications have been arranged into subsections for ease of use by designers. However, ratings have been arrived at through comparison of all roofing types shown across all subsections. The subsections are:

     - Flat roofs - 'cold deck', 'inverted deck' and 'warm deck', the position of the insulation being the primary difference between the systems.  A flat roof is a roof having a pitch not greater than 10° to the horizontal (BS6229:2003).

     - Low pitched roofs - e.g. profiled roof decking, composite cladding panels, etc up to a 15° pitch.

     - Pitched roofs - e.g. roofs with a pitch of greater than 15°, including tiled roofs on a timber roof structure and profiled sheet roofing.

    For Attic Roofs, where the space within the pitched roof is occupied, please use the pitched roof ratings. These will underestimate the material used in the pitch, due to the increased pitch but overestimate the material used horizontally as this is assessed as a floor.

    BREEAM 2008 Schemes to which this element applies:
    roofs chart
    View this as a full page (PDF file)

    Please select the element type of Roof Construction ratings you wish to review:


    For more information

    Call us on 0333 321 88 11 if you would like to know more, or email enquiries@bregroup.com.