It can depend on the municipality for their permit lengths and required inspections. Taking out the permit and inspection process a shingle roof if materials are available can take 3-4 days. A tile roof because of tile lead times can vary anywhere from 3 weeks up to 3 months. However, the tile underlayment is the waterproofing part of the roof and can be left waiting for tiles up to 6 months before it begins to degrade. Metal roofs depending on the difficulty;ty of the roof and how cut up it is can take 1 week to a month to complete.