Hi Claire
CIL Regulation 6(1)(d) states that for the purposes of CIL the conversion of any building previously used as single dwellinghouse to use as two or more seperate dwellinghouses is not to be treated as development.
This means that it is outside the scope of CIL and can be ignored (i.e. no need for a £zero CIL Liability Notice).
Therefore if someone has a building that is currently, or was last, used as a single dwelling, and they want to convert it to flats then it is outside the scope of CIL. There is no need for them to provide evidence of lawful use. Bristol's take is that provided that the previous use of the building was as a single dwelling and that it still has all its external walls and a roof and is watertight it can be converted to two or more dwellings with no need for CIL. You may want to check whether the building was last used as a single dwelling but if you're happy that it was then there is no CIL on converting it to two or more dwellings.
It is worth noting that if the building is in lawful use and the conversion also involves an extension, then CIL is payable on the extension because there is new build and the development involves the creation of a new dwelling. However if the building is not in lawful use and the development also involves an extension then CIL is payable on the whole lot (existing building and extension).
So to summarise:
Conversion of building last used as a single dwelling (irrespective of whether it is in lawful use) to two or more dwellings - outside the scope of CIL
Conversion and extension of a dwelling in lawful use that involves the creation of an additional dwelling - CIL payable on the extension
Conversion and extension of a dwelling not in lawful use that involves the creation of an additional dwelling - CIL payable on the lot.
Hope this helps - of course I may be wrong but this is the approach we have been taking for the past three years.
Jim
