Why does the building fail on Criterion 2, Walls or Floors, when all the external constructions are correctly insulated?
Posted by Andy Tindale on 06-Jul-16 10:23 AM
The failure is probably caused by a heated zone being adjacent to an unheated zone and the partition (wall or internal floor/ceiling) construction between them is uninsulated. To fix the problem either insulate the partition between the heated and unheated zones or heat the zones that are currenly unheated. Remember that 'heated' doesn't only cover zones that actually have a heat emitter installed but also covers zones that are indirectly heated by the adjacent zones. Do the 'unheated' zones really not benefit from heat from the heated zones, or are they really cold in winter? If they are cold in winter then the rest of the heated space must be insulated from them.
Also you find that even though the Criterion report seems to indicate a failure by showing the walls in red, the building may still pass Part-L.