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, Quarryville Borough administers the code: Section 150-1 of the Borough Code says "Quarryville Borough hereby elects to administer and enforce the provisions of the Pennsylvania Construction Code Act," Section 150-3 allows "the retention of one or more construction code officials or third-party agencies," and Section 150-7 C says "The municipal code official designated by Quarryville Borough is hereby authorized to conduct plan reviews and inspections, issue building permits." The Borough's Zoning and Building page lists Solanco Engineering Associates, 103 Fite Way, Suite C, Quarryville (717-786-0355), under "Zoning and Building Permits" with its building code official's credentials, and Commonwealth Code Inspection, 176 Doe Run Road, Manheim (717-664-2347), under "Plan Review and Code Inspections." The Borough office is at 300 St. Catherine St., Quarryville (717-786-2404). Section 150-8 says the chapter "specifically incorporates by reference the various codes adopted by the Department of Labor and Industry in the Pennsylvania Uniform Construction Code including, without limitation, the International Building Code 2003 and the International Fuel Gas Code 2003," and the Borough's pages name no code edition; this record has not read the 2003 editions' text and does not decide which edition the Borough applies.
Permit process
Quarryville Borough's Code and pages read for this record do not say whether a house reroof needs a permit. Chapter 150 of the Borough Code, Construction Codes, Uniform (effective July 8, 2004), says in Section 150-2 that "The Uniform Construction Code, contained in 34 Pa. Code, Chapters 401 through 405, as amended from time to time, is hereby adopted and incorporated herein by reference as the municipal building code of Quarryville Borough," adds no permit clause of its own for house repairs, and names no roof work. Section 150-5 keeps in effect building code ordinances adopted on or before July 1, 1999 "which equal or exceed the requirements of the code"; the Code's Disposition List shows a former Chapter 121, Building Permits ("Building Construction; Tree Removal; Roofing Materials; Privies," Ord. No. 100 of 1956), repealed June 1, 2020 by Ord. No. 439, and this record has not read its text. Chapter 420, Zoning, says in Section 420-1605 A "A zoning permit shall be required prior to the erection, construction or alteration of any building, structure or any portion thereof" and that it "shall be issued simultaneously with the required building permits"; it names no roof work, and Section 420-106 B defines "ALTERATION" as "Any change in or addition to the supporting members of a building or structure such as beams, bearing walls, columns, girders, joists, or rafters; enclosing walls; doors or windows, in exterior walls; or changing outside physical dimensions of the building or structure." This record does not decide whether a house reroof is an "alteration" under that definition or needs a Borough zoning permit. Section 420-1609 says the fee schedule "shall be posted in the office of the Zoning Officer"; none was found published. 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 Borough office (717-786-2404) or the code office on the Zoning and Building page before starting. The Borough office is open Monday to Friday 7:00 to 3:30 PM. Read for this answer: the Borough's home page and Zoning and Building page, and on eCode360 Chapter 150, Chapter 300 (Property Maintenance), Chapter 420 (Zoning, Article XVI Administration and the Section 420-106 definitions), former Chapter 121 as shown in the Disposition List, and every page of a search of the whole Borough Code for "roof" (18 results, none a permit provision for roof work) and for "reroofing" (no results).