VCONST04460 - Zero-rating major interest grants after a non-residential conversion: is the building the subject of a ‘non-residential conversion’: past use of the building
Even if a building is designed, or adapted for, residential use and is over 10 years old, it will still qualify as a ‘non-residential’ building if it has not been used as a dwelling or for a ‘relevant residential purpose’ in the 10 years prior to the grant.