Adopted building code
The 2021 International Residential Code, as adopted by the State in the Pennsylvania Uniform Construction Code (UCC). 34 Pa. Code 403.21(a)(7) adopts "The 'International Residential Code of 2021,' except that:" followed by the State's list of exclusions and modifications, effective January 1, 2026 (55 Pa.B. 7701). None of the State's changes touches Chapter 9, Roof Assemblies, or Section R803, Roof Sheathing, so those apply as the International Code Council publishes them. Work on existing buildings is also pointed to the State's existing-building code: "The repair, alteration, change of occupancy, addition and relocation of existing buildings must comply with Chapter 34 of the 'International Building Code of 2021' or with the 'International Existing Building Code of 2021'" (34 Pa. Code 403.21(f)). The UCC is the minimum everywhere in the state: "no municipality may propose or enact any ordinance which is less than the minimum requirement of the Uniform Construction Code" (Pennsylvania Construction Code Act, Act 45 of 1999, section 503(b)). The Act also lists work it "shall not apply to", including "Alterations to residential buildings which do not make structural changes or changes to means of egress" or to "Repairs to residential buildings," in each case "except as might be required by ordinances" kept in force under section 303(b)(1) or adopted under section 503 (Act 45 section 104(b)(5) and (6); 34 Pa. Code 403.1(b)(8) and (9)). The Act defines a repair as "The reconstruction or renewal of any part of an existing building for the purpose of its maintenance." So whether the code's roofing rules reach a given house reroof depends on the municipality's own ordinances. Everything above is Pennsylvania state law, the same in every municipality. Locally, Marietta Borough administers the code through a retained firm: its Resolution 04-2026 says "the Building Code Official for the Borough of Marietta from January 5, 2026 through the date of the Organizational Meeting to be held in January of 2028, unless changed by Resolution of the Borough Council, shall be the firm of Commonwealth Code Inspection Services, Inc.," and the Borough's posted Uniform Construction Code page (a scan) says "Commonwealth Code Inspection Services, Inc. of Manheim, PA, has been contracted to provide UCC plan review and inspection services for Marietta Borough." The Borough office is at 111 East Market Street. Chapter 135 of the Borough Code, the Marietta Borough Construction Code Ordinance (adopted June 8, 2004, read October 12, 2026), says in Section 135-3 "The Borough hereby adopts the standards which the Pennsylvania Department of Labor and Industry has made part of the Pennsylvania Uniform Construction Code identified in § 403.21 of the L & I regulations as the Marietta Borough Construction Code," adds definitions and a few table entries, and in Section 135-4H adopts 34 Pa. Code 403.62 among the sections "to govern applications for and issuance of construction code permits for nonresidential and residential construction." It names no roof work and adds no permit clause of its own for house repairs, and its Section 135-2B says the chapter "does not adopt the International Property Maintenance Code." Every page of a search of the whole Borough Code for "roof" and for "reroofing" found no permit provision naming roof work. The Borough's Uniform Construction Code page lists the "International Residential Code 2003," while Chapter 135 names no edition; the text above is the 2021 edition's, this record has not read the 2003 edition's text, and this record does not decide which edition the Borough applies to a house.
Permit process
Marietta Borough's code and pages read for this record do not say whether a house reroof needs a permit. Chapter 135 of the Borough Code, the Marietta Borough Construction Code Ordinance (adopted June 8, 2004, read October 12, 2026), says in Section 135-3 "The Borough hereby adopts the standards which the Pennsylvania Department of Labor and Industry has made part of the Pennsylvania Uniform Construction Code identified in § 403.21 of the L & I regulations as the Marietta Borough Construction Code," adds definitions and a few table entries, and in Section 135-4H adopts 34 Pa. Code 403.62 among the sections "to govern applications for and issuance of construction code permits for nonresidential and residential construction." It names no roof work and adds no permit clause of its own for house repairs, and its Section 135-2B says the chapter "does not adopt the International Property Maintenance Code." Every page of a search of the whole Borough Code for "roof" and for "reroofing" found no permit provision naming roof work. The Borough's Application for Zoning Permit/Certificate (a scan) lists as types of permit "Alteration to existing building" and names no roofing, and its fee resolution lists under "CONSTRUCTION CODE (UCC)" a "Construction Permit" line without naming roof work. The Borough posts no residential roofing form or "do I need a permit" list. Under state law, Act 45 section 104(b)(5) and (6) list "Alterations to residential buildings which do not make structural changes or changes to means of egress" and "Repairs to residential buildings" among work the Act does not apply to, "except as might be required by ordinances in effect pursuant to section 303(b)(1) or adopted pursuant to section 503," and 34 Pa. Code 403.62(c) says "A permit is not required for the exceptions listed in § 403.1(b) (relating to scope) and the following, if the work does not violate a law or ordinance." This record does not state whether the Borough requires a permit for a house reroof; ask the Borough office (717-426-4143) before starting. Read for this answer: Chapter 135 of the Borough Code in full; every page of a search of the Borough Code for "roof" and "reroofing"; the Borough's home and Documents pages; its Uniform Construction Code page, zoning permit application and fee resolution; and Resolution 04-2026 (the three PDFs are scans, read from the rendered pages).