To translate the above simply – in mixed function buildings, the way to determine the type of benchmark used to compare with the whole building being assessed, is to use whichever function that takes up ≥50% of the building’s net internal area.

For example, if the NIA for a mixed use building is 85% residential and 15% commercial, the whole building will be compared with a residential benchmark. If the NIA is 50% commercial, 25% retail & 25% residential then a commercial benchmark will be used.