VCONST08220 | Zero-rating the ‘approved alteration’ of a ‘protected building’: is the work to a ‘protected building’: identifying the building
From HM Revenue & Customs · VAT Construction
Group 6 of Schedule 8 refers to a ‘protected building’ in the singular (but check VCONST08240 for garages). To qualify for zero-rating, the works in question must be to that building.