The new v11.1 conventions for RdSAP will come into force on the 1st December and is split into two convention items. These will read as follows:
After applying Convention 1.01, for a conversion of a building originally intended to be heated (e.g. a non-domestic building converted into a house or flats, for example a school, a hotel, a community hall or other) or where a dwelling has been sub-divided (e.g. larger house converted to flats) always use the original construction date, and specify upgraded elements only where documentary or visual evidence is available.
After applying Convention 1.01, for a conversion of an unheated building (e.g. barn, farm building, warehouse, mill building, train station, workshop and similar) use the conversion date as the date of construction, based on the documentary evidence, e.g. the date of building control sign off or the date and details of installed insulation (if available) on the Local authority Planning Portal (England and Wales), relevant local authority Building Standards Register (Scotland) or relevant District Council Building Control (Northern Ireland). Specify details of elements upgraded after the date of conversion only where documentary or visual evidence is available.