# The Town and Country Planning General Development Order 1988, Paragraph A.1: Development not permitted


Development is not permitted by Class A if—
(a) the cubic content of the resulting building would exceed the cubic content of the original dwellinghouse—
(i) in the case of a terrace house or in the case of a dwellinghouse on article 1(5) land, by more than 50 cubic metres or 10%, whichever is the greater;
(ii) in any other case, by more than 70 cubic metres or 15%, whichever is the greater;
(iii) in any case, by more than 115 cubic metres;
(b) the height of the resulting building would exceed the height of the highest part of the roof of the original dwellinghouse;
(c) any part of the resulting building would be nearer to any highway which bounds its curtilage than—
(i) the part of the original dwellinghouse nearest to that highway; or
(ii) 20 metres,
whichever is nearest to the highway;
(d) any part of the resulting building which is within 2 metres of the boundary of the curtilage of the dwellinghouse would exceed 4 metres in height;
(e) the total area of ground covered by buildings within the curtilage (other than the original dwellinghouse) would exceed 50% of the total area of the curtilage (excluding the ground area of the original dwellinghouse);
(f) it would consist of or include the installation, alteration or replacement of a satellite antenna;
(g) it would consist of or include the erection of a building within the curtilage of a listed building; or
(h) it would consist of or include an alteration to any part of the roof.

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Source: https://www.legislation.gov.uk/uksi/1988/1813/schedule/2/part/1/chapter/1/paragraph/A.1 (the official version)
Page: https://openlegislation.uk/town-and-country-planning-general-development-order-1988/schedule-2/part-1/chapter-1/paragraph-A.1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.