Regulation 4

one or more dwelling-houses are existing at the time of the application for planning permission or conservation permission for the development and the existing dwelling-house or dwelling‑houses are to be demolished; or

one or more dwelling-houses had existed at any time before the application for planning permission or conservation permission for the development.

entitles a person to carry out a development to add floor area for residential use to an existing dwelling‑house erected on one or more lots of land where there is no other dwelling‑house erected on such lot or lots of land; and

is given in relation to an existing dwelling-house in respect of which the initial period, where applicable, has ended.

entitles a person to carry out a development to add floor area for residential use to an existing dwelling‑house that was erected on one or more lots of land where there is no other dwelling‑house erected on such lot or lots of land;

is given in relation to an existing dwelling‑house in respect of which the initial period, where applicable, has not ended; and

on completion of that development, the total floor area of the existing dwelling‑house does not increase by more than 20 square metres over and above the total floor area of the existing dwelling‑house as authorised in the planning permission or conservation permission for the erection of the existing dwelling‑house.

a dwelling-house erected on one or more lots of land where there is no other dwelling‑house erected on such lot or lots of land has an initial period if the erection of the dwelling‑house was authorised by the same chargeable consent as for one or more other dwelling‑houses on other lot or lots of land; and

the initial period of any dwelling-house mentioned in sub‑paragraph (a) is 3 years starting after the date the following were granted for its erection:

a temporary occupation permit;

a certificate of statutory completion where no temporary occupation permit had been granted.