reg 5 Meaning of material change of use
For the purposes of paragraph 8(1)(e) of Schedule 1 to the Act and for the purposes of these Regulations, there is a material change of use where there is a change in the purposes for which or the circumstances in which a building is used, so that after that change— (a) the building is used as a dwelling, where previously it was not; (b) the building contains a flat, where previously it did not; (c) the building is used as an hotel or a boarding house, where previously it was not; (d) the building is used as an institution, where previously it was not; (e) the building is used as a public building, where previously it was not; (f) the building is not a building described in classes 1 to 6 in Schedule 2, where previously it was; (g) the building, which contains at least one dwelling, contains a greater or lesser number of dwellings than it did previously; (h) the building contains a room for residential purposes, where previously it did not; (i) the building, which contains at least one room for residential purposes, contains a greater or lesser number of such rooms than it did previously; ... (j) the building is used as a shop, where previously it was not ; or (k) the building is a building described in regulation 7(4)(a), where previously it was not .