First of all, the homeowner should always do their research to determine if the contractor they are hiring to perform the work is actually licensed and insured. They should always check the BBB for the company rating and any reviews posted online. This is a great tool to weed out shady contractors. The homeowner should always be presented with a scope of work and expectations of the job which will include a signed contract, work order and any other pertinent documents necessary to the job. In addition, all homeowners should ask for a copy of the business license and proof of insurance in the event this wasn’t already presented during their initial meeting with the contractor. This is standard practice with a reputable company. If the homeowner selects a reputable roofer to perform the work then they should have no problem providing the documentation. Again, this will identify who will be performing the work and their credentials.
Typically unless written in the contract otherwise, at the end of the job the roofer is responsible to clean up the debris and haul it away which would include but not limited to using a magnet to pick up nails. This is common practice across the industry. However, even when the magnet is used properly and thoroughly it’s not possible to get every single piece of metal that may drop in ones yard.
This is an unfortunate situation, however, this is a common problem among all roofing companies. If you will, the roofers are on top of the roof slinging debris over the edge to the ground. It’s likely debris can go just about anywhere and get lodged into the ground. My company policy has always been to have my roofers use the magnet after all debris is cleaned up and we do this for every single job. In addition, typically the same day or the following day my quality control lead does a final inspection of the roof which includes using the magnet a 2nd time to minimize stray metal that was previously missed by the roofers. This is our policy for every single job and we have the homeowner sign the final inspection showing this was completed to their satisfaction.