A lot of the answers so far are rather idealistic.
The vast amount of construction demolition is thrown away into landfills.
Machines and equipment that remain are usually what’s left that the owner couldn’t sell or recover. Buildings that have wood or metal decorations may be visited by salvagers looking to resale parts, but this is as likely stolen as given away. Many contractors just think of it as one thing less that they need to haul away.
For the most part, any recycling done is forced on the owner and contractor by local cities or counties. While most people think you would recover money from recycling, this is less the case in construction. The labor to sort and haul the material generally outweigh the cost recovery. Plus, the local municipalities require greater record-keeping for recycling activities than demolition.
While it is good for the environment it just isn’t the money-making scenario most make it out to be.
MKDesign 