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, The City of Clairton elects to administer and enforce the Pennsylvania Construction Code Act (Section 171-1 of the City Code) and takes building permit applications on its own form at the City offices, 551 Ravensburg Boulevard, approved by the City's Code Enforcement Officer; no City page read for this record names a third-party agency for the code work. Section 171-2 adopts the Uniform Construction Code, "as amended from time to time," as the municipal building code of the City, and Chapter 171 changes nothing in the code's roofing provisions. Chapter 163 of the City Code adopts the "BOCA National Building Code, Twelfth Edition, 1993," and the City's pages name no code edition; this record has not read that code's text and does not decide which code the City applies to a house reroof.
Permit process
No City of Clairton page or form read for this record says whether a residential reroof needs a building permit. The City's application for a permit leaves the permit type blank ("APPLICATION FOR: _____________________________PERMIT") and names no roof work, and the City's Forms page lists a Building Permit, a Contractor License Application and an Occupancy Permit Application and nothing on roofing. Chapter 171 of the City Code, Construction Codes, Uniform (Ord. No. 1752, 2004), adopts the Uniform Construction Code "as amended from time to time" and adds no permit clause of its own; Section 171-5A keeps in force building code ordinances adopted on or before July 1, 1999 "which equal or exceed the requirements of the code." Chapter 163, adopted in 1994, adopts "for the purpose of establishing rules and regulations for the construction, alteration, equipment, fire protection and safety of buildings and structures, including administration, building permits and penalties," the "BOCA National Building Code, Twelfth Edition, 1993," and its amendments set a fee schedule for "Single-Family Residential Building Permits" by construction cost with no roofing line. This record has not read that model code's permit sections and does not decide whether Chapter 163 is kept in force for house repairs. No section of the City Code read names roof work as permit work or as exempt. 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." Inside the district the City Code designates the "Restricted Fire Limits," Section 199-5 says that "the roof, when damaged or repaired to the extent of 50% or more of the area thereof, shall be wholly covered with tin, sheet iron, slate or other incombustible material." Chapter 215 of the City Code says "It shall be unlawful to engage in business in the City of Clairton as a home/commercial contractor without first having obtained a license therefor," defines that contractor to include home improvements "such as roof, siding, soffit and fascia," and sets the licence fee at $25. The City's permit conditions ask for "A signed copy of the contract between the property owner and the contractor" and say "Contractors must submit Worker's Compensation and Liability Insurance coverage certificate issued to the Municipality." The City offices are at 412-233-8113. Read for this answer: Chapter 171 of the City Code, Construction Codes, Uniform, Chapter 163, Building Construction, Article I of Chapter 199, Fire Limits, and Chapter 215, Home Contractors, in full; Article I of Chapter 195, Fees; every page of a search of the whole City Code for "roof," "roofing" and "reroofing"; and the City's Forms and Contact pages, building permit application and contractor license application.