The costs to demolish a house are usually calculated by the square metre. In some cases, demolition work is calculated on an hourly basis. Depending on the size of the area that needs to be removed, the materials of the house and whether any hazardous materials need to be removed, the removal of foundations, site accessibility, the equipment and number of personnel needed to complete the job, the costs will vary. Before agreeing on a demolition, a quality home builder will provide you with estimated costs and timeframes based on rigorous site inspections