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, Delmar Township takes permit applications at its Township Building, 610 N Lawton Road, Wellsboro (570-724-5482), and its Forms & Permits page lists a "Building Permit" form. The form is headed "Delmar Township Supervisors Building Permit" and says "Delmar township code officer will conduct inspections," and Section 1103 F of the Township's Zoning Ordinance says the Zoning Officer "shall forward the approved application to the Township Code Official." The Township's pages read name no outside code agency. The Township's ordinance adopting the Uniform Construction Code was not found on the Township's website, whose Documents page lists only its adopted Subdivision and Land Development Ordinance, Zoning Ordinance and zoning maps, and was not read for this record. The building permit form's "Type of project" list names new buildings, additions, a "Structural alteration," decks, garages and similar projects, and names no roof work. Section 1102 A of the Zoning Ordinance (adopted December 2, 2019) says "A zoning permit shall be required prior to the erection, construction, reconstruction, conversion, alteration or replacement of structural bearing, relocation, change in height, square footage, roof line, basic structure, lot coverage, dimensions, repair, maintenance, addition, alteration, enlargement, razing or removal of any building or portion thereof," and Section 1103 E says "No zoning permit shall be required in cases of normal maintenance activities, minor repairs and alterations to existing buildings or structures, provided that no structural changes or modifications are involved." The Ordinance does not name reroofing or roof replacement, and does not define "minor repairs" or "normal maintenance"; this record does not decide whether a house reroof is a minor repair, normal maintenance or an alteration, or needs a zoning permit. The Township's pages name no code edition.
Permit process
Delmar Township's pages read for this record do not say whether a house reroof needs a permit. The Township's ordinance adopting the Uniform Construction Code was not found on the Township's website, whose Documents page lists only its adopted Subdivision and Land Development Ordinance, Zoning Ordinance and zoning maps, and was not read for this record. The building permit form's "Type of project" list names new buildings, additions, a "Structural alteration," decks, garages and similar projects, and names no roof work. Section 1102 A of the Zoning Ordinance (adopted December 2, 2019) says "A zoning permit shall be required prior to the erection, construction, reconstruction, conversion, alteration or replacement of structural bearing, relocation, change in height, square footage, roof line, basic structure, lot coverage, dimensions, repair, maintenance, addition, alteration, enlargement, razing or removal of any building or portion thereof," and Section 1103 E says "No zoning permit shall be required in cases of normal maintenance activities, minor repairs and alterations to existing buildings or structures, provided that no structural changes or modifications are involved." The Ordinance does not name reroofing or roof replacement, and does not define "minor repairs" or "normal maintenance"; this record does not decide whether a house reroof is a minor repair, normal maintenance or an alteration, or needs a zoning permit. 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." Ask the Township secretary (570-724-5482) before starting; the Township's Office Hours page gives secretary hours of Monday to Friday 7:00 AM to 11:00 AM. The building permit form says "If construction is not started within six (6) months the permit will be null and void." Read for this answer: the Township's home, Forms & Permits, Documents, Office Hours and Contact pages; its building permit form and setbacks sheet (scanned, read by text recognition); and its Zoning Ordinance of December 2, 2019 (searched in full for roofing, building permit, repair and alteration provisions).