Have a croof being removed and cedar shake roof beiing removed.And an asphalt shingle put in it's place.After removing the cedar shake roofinf material,new sub-roofing is being installed as I am writing this .It is being installed directly over top of the existing sheet,with no observable inspection for any water damage.Is this correct?They are useing 3/4 inch particle board.This is a southern Oregon project.The contractor is a well known individual,and very kind to speak with.I am watching over this project for my daughter and would like the best results for her.Is there anyone out there with some input?