CA93700 | Structures and buildings allowance (SBA): qualifying expenditure: qualifying capital expenditure: qualifying capital expenditure on purchase of used building from a developer
From HM Revenue & Customs · Capital Allowances Manual
If a developer CA93600 has incurred expenditure on the construction of a building, and sold the relevant interest in that building in the course of their development trade after the building has been used, the qualifying capital expenditure is the expenditure incurred by the developer on construction.