CG64719 - Private residence relief: letting: building not a dwelling-house
The instruction at CG64320 explains that a person who has a residence in a building which is not a dwelling-house may be allowed private residence relief by treating the rooms occupied as the person’s residence as if they were themselves a dwelling-house.
If some of these rooms are let for a time as residential accommodation, then lettings relief will be available under s223B TCGA92/(or s223(4) TCGA92 where the disposal was before 6 April 2020). But if any part of the rest of the building not forming part of the dwelling-house is let as residential accommodation lettings relief will not be due.