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, Steelton Borough administers the code itself: Section 108-3 of the Borough Code says "The Borough of Steelton hereby elects to administer and enforce the provisions of the Pennsylvania Construction Code Act," residential permits are filed in person with the Borough's Codes Department at 123 North Front Street, Steelton, on the 3rd floor, and the Borough's Permits FAQs page says "Commercial permits are processed and inspected by CCIS (Commonwealth Code Inspection Services)." Section 108-4 adopts the Uniform Construction Code, contained in 34 Pa. Code Chapters 401 to 405, "as amended from time to time," as the municipal building code, and Chapter 108 changes nothing in the code's roofing provisions. The Borough's Permits FAQs page answers "What codes does the Borough of Steelton utilize?" with "The 2015 International Building Code 2015 (IBC 2015)" and names no residential code edition, and the Borough's residential permit application, revised in 2014, lists "Applicable Codes: 2009 IBC/IRC"; the text above is the 2021 edition's, the 2009 edition's text was not read for this record, and this record does not decide which edition the Borough applies.
Permit process
Steelton's code requires a permit to repair a building but exempts minor repairs not involving structural work to roofs, without defining a minor repair. Section 2-5 of the Borough Code, part of the Code Enforcement Ordinance (Ord. No. 82-5, 1982), says "Permits are required to repair, construct, enlarge, alter or demolish a building or structure" and "Permits are not required for minor repairs not involving structural work to floors, walls, ceilings and roofs." The Borough Code does not define a minor repair. Section 108-7A keeps in force building code ordinances adopted on or before July 1, 1999 "which equal or exceed the requirements of the code"; this record does not decide whether Section 2-5 is one of them. The Borough's Codes Department and Permits FAQs pages (read October 9, 2026) say nothing on roof work, and the Borough's residential permit application lists "Repair/Replacement" among its improvement types with no roofing box. The Borough publishes no permit fee schedule; Section 2-7 sets fees "by resolution of the Borough Council." 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." Because whether an ordinary reroof is a minor repair turns on a word the Borough Code does not define and the Borough has not applied to reroofs, this record does not decide whether the Borough requires a permit for an ordinary reroof. Ask the Codes Department at 717-939-1146 before work starts. Section 2-7B says anyone who starts work needing a permit without one shall "pay double the permit fee fixed for such work," except for emergency work and first-time offenders. Permits must be submitted in person; the Borough office is open Monday to Thursday, 7:00 a.m. to 4:30 p.m., and Friday, 7:00 a.m. to 4:00 p.m. Read for this answer: Chapter 2, Code Enforcement, Chapter 44, Building Construction, and Chapter 108, Uniform Construction Codes, of the Borough Code, in full; every page of a search of the whole Borough Code for "roof" and for "reroofing"; the Borough's Codes Department, Permits FAQs and Contact pages; and its residential permit and zoning permit applications.