How much should a roofer charge to replace the bad ones and fully treat the shake roof? I know that it all depends on the size of the roof but is there a basic price per sq. foot that y'all go by? I have a roof that is 25 years old on the house I just bought. I was there when my home inspector did the roof inspection and he said it looked really good. He estimates at least about four years of life left. Would this roof be worth trying to preserve? We are saving for a new one though. My homes sq footage is 2300. It is a two story home with an attached two car garage that is fully shaked. Thank you.