Appendix A: Work to thermal elements

  1. Work to thermal elements

    Work to thermal elements

    1 Where the renovation of an individual thermal element constitutes a major renovation; or amounts to the renovation of more than 50% of the element’s surface area, an opportunity exists for cost-effective insulation improvements to be undertaken at marginal additional cost. This appendix provides guidance on the cost- effectiveness of insulation measures when undertaking various types of work on a thermal element.

    2 Table A1 sets out the circumstances and the level of performance that would be considered reasonable provision in ordinary circumstances. When dealing with existing dwellings some flexibility in the application of standards is necessary to ensure that the context of each scheme can be taken into account while securing, as far as possible, the reasonable improvement. The final column in Table A1 provides guidance on a number of specific issues that may need to be considered in determining an appropriate course of action. As part of this flexible approach, it will be necessary to take into account technical risk and practicality in relation to the dwelling under consideration and the possible impacts on any adjoining building. In general the proposed works should take account of:

    a. the requirements of any other relevant parts of Schedule 1 to the Building Regulations;

    b. the general guidance on technical risk relating to insulation improvements contained in BR 262¹¹;

    c. for buildings falling within the categories set out in paragraphs 3.7 to 3.8, the guidance produced by English Heritage.

    Where it is not reasonable in the context of the works project to achieve the performance set out in Table A1 the level of performance achieved should be as close to this as practically possible.

    3 Table A1 incorporates, in outline form, examples of construction that would achieve the proposed performance, but designers are free to use any appropriate construction that satisfies the energy performance standard, so long as they do not compromise performance with respect to any other part of the Building Regulations.

    4 General guidance is available from such sources as the Energy Saving Trust and relevant British Standards.

    [11] BR 262 Thermal insulation: Avoiding risks, BRE, 2002.

    [12] Specification of thickness of insulation is based on lambda values (conductivity) of 0.04 W/(m.K).

    Table A1 Cost-effective U-value targets when undertaking renovation works to thermal elements

    Table A1 Cost-effective U-value targets when undertaking renovation works to thermal elements

    Table A1 Cost-effective U-value targets when undertaking renovation works to thermal elements

    Table A1 Cost-effective U-value targets when undertaking renovation works to thermal elements