Demolition

From Swikipedia

Introduction

Any building work which involves demolishing and rebuilding 50% or more of the external walls. Where a facade is retained (eg for heritage/building conservation reasons), this is still a demolition if a substantially new building is built behind the old facade.

Demolition is the tearing-down of buildings and other structures, the opposite of construction. Demolition contrasts with deconstruction, which involves taking a building apart while carefully preserving valuable elements for re-use.

For small buildings, such as houses, that are only two or three stories high, demolition is a rather simple process. The building is pulled down either manually or mechanically using large hydraulic equipment: elevated work platforms, cranes, excavators or bulldozers. Larger buildings may require the use of a wrecking ball, a heavy weight on a cable that is swung by a crane into the side of the buildings.