What are building and works?

The definitions of building and works:
Building includes-

(a) a structure and part of a building or a structure; and
(b) fences, walls, out-buildings, service installations and other appurtenances of a building; and
(c) a boat or a pontoon which is permanently moored or fixed to land;

Works includes any change to the natural or existing condition or topography of land including the removal, destruction or lopping of trees and the removal of vegetation or topsoil.

Source: Planning and Environment Act 1987- Section 3 by the Department of Transport and Planning