The only real uncertainties are the things that cannot be viewed until the roof stripped off. We will perform an extremely though inspection of the existing system and attempt to identify things like soft decking that may need to be replaced, high or low trusses, improper or inadequate attic ventilation, rotten fascia boards, damage to chimneys and flashing where the roof meets the wall. By preforming a detailed inspection will be able to take most of the uncertainty out of the process.