Shingle replacement does not require a permit. Minor repairs to decking during shingle replacement is permitted and does not require a permit. If roof decking is being replaced in its entirety, a Miscellaneous Permit Application is required and must comply with the 2018 International Residential Code (IRC). In most cases the Span Rating is 24/16, so the decking thickness required is 7/16” (Refer to Table R503.2.1.1(1) of the IRC).
Commercial roofs can be complicated because there are so many variations of them. If you have questions about commercial roof repairs or replacement, please begin with an email to firstname.lastname@example.org. Please provide the address and explain the nature of the issue/project.