Building Codes, Standards and Permit Requirements
Which code applies
Michigan adopts the Michigan Residential Code for one- and two-family dwellings and townhouses, and the Michigan Building Code for everything else; both derive from the International Codes with state amendments. Roofing is permitted and inspected work in most jurisdictions - a re-roof normally needs a permit and at least a final inspection.
Requirements candidates must know
Slope limits for each covering; ice-dam protection extending from the eave to at least 24 inches inside the exterior wall line where the average January temperature is 25 degrees F or lower, which covers essentially all of Michigan; underlayment requirements by slope; attic ventilation ratios (commonly one square foot of net free vent area per 150 square feet of attic floor, split high and low); fastener schedules; and limits on the number of roof layers.
Permits and inspections
Expect a sheathing or in-progress inspection and a final. Keep the approved plans on site, post the permit, and call for inspection before covering anything that must be seen.
Licensing and standards
Michigan regulates residential contractors through LARA, and roofing on residential structures falls under the residential maintenance and alteration license. Manufacturers' published installation instructions are enforceable as part of the code - installing a product against its listing is a code violation.
Trap
Questions imply that a re-roof needs no permit, or that manufacturer instructions are only recommendations. Both are wrong.
Rule of thumb
When the code and the product label conflict, follow the stricter requirement and document the decision in the job file.