Contracts for setting equipment on towers, grain bins, etc..

I currently have a contract to model on placing a new tower on landowner’s property.

I need some kind of agreement for existing structures such as city water towers and grain bin type structures.

Can anyone point me in a general direction or might have a contract that I can model after.

I understand that I would not be able to view the entire contract, but if some one could point out some highlights of such contract would greatly appreciate.