Demolition in the construction sector means the bringing down of buildings and other structures that are load-bearing or otherwise related to the physical integrity of the structure. Demolition is often done in combination with site clearing i.e. disposing of the rubble and waste material. In the NACE (revision II) concept, demolition is a subcategory of construction, listed as specialised construction activities (Division F-43) further subdivided into Demolition and site preparation (Group: F-43.1) – indicating that demolition may precede the building of new structures – and having finally the lowest possible subcategory: Demolition (Class: C-43.11).
As a demolition and the following site clearance may involve unearthing the foundations, also excavation activities may play a role.
Dismantling is seen as a partial demolition, i.e. the removal of a component of a structure often with a replacement by a new part (e.g. exchange of boilers).
A relatively new term is deconstruction, meaning to take a building or structure apart in order to preserve valuable elements for re-use (“green demolition”).
There are three principal ways of demolition: take the structure down piecemeal; knock it or push it down; or blast it down using explosives. The choice of method is dictated by the condition of the structure, its surroundings, the reasons for the demolition and cost. Use of explosives will usually be the fastest way of demolition but may not be possible when other buildings are close by. In case demolition must not generate dust and noise usually manual processes will be applied.