Jersey RdSAP Convention 3.14

Within RdSAP, it is not necessary to change the U-value of a building element from the default 'as built' values based on the dwelling age band.

If insulation is added, the retro-installed thickness can be entered, and the calculation engine will assume an appropriate U-value for the element.

Where these defaults have been overwritten, you must be able to provide specific documentary evidence that the U-value has been:

    1. Calculated for the whole element, not just insulation;

    2. Produced by a suitably qualified person;

    3. Produced in with BRE "Conventions for U-Value Calculations".