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, Lower Chichester Township, in Delaware County, takes building permit applications at its Township office, 1410 Market Street, Linwood, on its own "TOWNSHIP OF LOWER CHICHESTER" building permit application, and its Officials page lists "Code Enforcement and BCO:" "BNO Inspections", a third-party code firm. Part Fourteen of the Township's Codified Ordinances, posted on its site and compiled "Complete to March 1, 2011," was read in full. Section 1428.01 adopts "The Uniform Construction Code, contained in 34 PA Code, Chapters 401 – 405, as amended from time to time" as the Municipal Building Code, and Section 1428.03(a) keeps in force building code ordinances "adopted by the Township on or before July 1, 1999, and which equal or exceed the requirements of the code." Section 1442.01 (Ord. 288, 1954) says "No person shall proceed with the erection, alteration or enlargement of any building or structure, or any part thereof, in the Township, unless application for a permit shall have been made"; Section 1442.02 (Ord. 86-6, 1986) sets "A fee for building permits for construction, alteration or repair"; and Section 1442.13 says "No person shall erect, remove, alter or repair, or do or cause to be done any work in the erection, removal, alteration or repair of any building, without first obtaining the proper permits required by this chapter." None of these sections names roof work, and this record does not decide whether they reach a house reroof or how they sit with the Uniform Construction Code. Section 1420.03 (Ord. 2010-01) adopts the "International Residential Code, 2009", Section 1428.01 adopts the Uniform Construction Code "as amended from time to time," and no Township page read names a current edition; this record has not read the 2009 edition's text and does not decide which edition the Township applies to houses.
Permit process
Lower Chichester Township's code has general permit clauses for alteration and repair work that name no roof work, and its pages do not say whether a house reroof needs a permit; call the Township office at 610-485-1472 before starting. Part Fourteen of the Township's Codified Ordinances, posted on its site and compiled "Complete to March 1, 2011," was read in full. Section 1428.01 adopts "The Uniform Construction Code, contained in 34 PA Code, Chapters 401 – 405, as amended from time to time" as the Municipal Building Code, and Section 1428.03(a) keeps in force building code ordinances "adopted by the Township on or before July 1, 1999, and which equal or exceed the requirements of the code." Section 1442.01 (Ord. 288, 1954) says "No person shall proceed with the erection, alteration or enlargement of any building or structure, or any part thereof, in the Township, unless application for a permit shall have been made"; Section 1442.02 (Ord. 86-6, 1986) sets "A fee for building permits for construction, alteration or repair"; and Section 1442.13 says "No person shall erect, remove, alter or repair, or do or cause to be done any work in the erection, removal, alteration or repair of any building, without first obtaining the proper permits required by this chapter." None of these sections names roof work, and this record does not decide whether they reach a house reroof or how they sit with the Uniform Construction Code. The Township's building permit application is headed "APPLICATION FOR PERMITS: FOR ADDITIONS, ALTERATIONS, REPAIRS, ONE STORY STRUCTURES, DEMOLITION, ETC." and has no roof box, and its Permits page lists residential permit fees by estimated cost with no roof line. Pennsylvania's Department of Labor and Industry lists, for Lower Chichester Township, a filing that "Proposes requiring a building permit for all alterations and repairs to residential buildings as required by the IBC 2009," with an approval letter mailed 01/02/2015; its listing shows no enactment date for that filing, and this record has not found or read such an ordinance. 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." Read for this answer: Part Fourteen of the Township's Codified Ordinances in full; the Township's Permits, Officials and Ordinances pages; and its building permit application.