material change in the use of a building (3) For the avoidance of doubt in determining, for the purposes of this Act, what constitutes a material change in the use of a building, it is declared that- (a) any increase in the number of units in a building to more than the number originally approved by any authority empowered under any written law to give the approval involves a material change in the use of the building; (b) the use as a dwelling-house of a building not originally constructed for human habitation involves a material change in the use of the building; (c) any alteration or addition to that part of the building, whether in the interior or attached to the exterior of the building, that abuts upon any regular line of street as prescribed by or defined in any written law relating to buildings involves a material change in the use of the building; (d) any use of a building or part thereof that contravenes or is inconsistent with or contrary to any provision of the development plan involves a material change in the use of the building; (e) the use for other purposes of a building or part thereof originally constructed as a dwelling-house involves a material change in the use of the building. ACT 172 - TOWN AND COUNTRY PLANNING ACT 1976 2. Interpretation.