What do builders use to knock down buildings?

It depends on the type of building, if you want to save any of the materials, and what tools you have available. - I have knocked down old buildings by hand, with hammer and crowbars to preserve old bricks, stonework and fine woodwork, -on the other hand if it was a cheaply built structure with nothing special about it, an excavator or back-hoe could simply crush it and put all the pieces in a demolition bin.