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, Towanda Borough takes permit applications at its Borough office, 724 Main Street (570-265-2696), and its Building / Zoning Permits page offers "Residential & Commercial Building Permits / Sign & Zoning Permit Applications / Zoning Hearing Board Applications" and an online application portal. Section 112-32 of the Borough Code says the Borough "hereby elects to administer and enforce the provisions of the Pennsylvania Construction Code Act," and Section 112-34 lets it do so through "the retention of one or more construction code officials or third-party agencies." The Borough's residential construction permit application says that "Code Inspections, Inc. requests a minimum of the primary contractor information to be provided in case correspondence or contact is necessary," and the Borough's fee schedule says "3rd party fees are actual cost + admin fees." Section 112-33 of the Borough Code (Article VIII, adopted May 3, 2004) says "The Uniform Construction Code, contained in 34 Pa. Code, Chapters 401-405, as amended from time to time, is hereby adopted and incorporated herein by reference as the municipal building code of this municipality," and Section 112-36 keeps in effect building code ordinances adopted on or before July 1, 1999 "which equal or exceed the requirements of the code." Section 112-37 B of the same article says "Although a permit is required, there shall be no fee for work valued at under $500." Article II of Chapter 112, a Building Code article adopted in 1969 that names the "2006 International Building Code," says in Section 112-11 B(2) that "There shall be no fee for any work that is routine maintenance and upkeep, for example, painting, siding repairs, replacing sidewalks, blowing insulation into the house, replacing roofing or any internal work, such as carpentry that does not exceed $500, provided that this does not include electrical or plumbing work." Both lines speak to fees; neither says whether a house reroof needs a permit, and this record does not decide whether it does. Chapter 325 of the Borough Code (Zoning) says in Section 325-66 A(1) that "A building and/or zoning permit shall be required prior to" "The erection, addition or alteration of any building or portion thereof"; it names no roof work and gives no relief for repairs, and this record does not decide whether a house reroof is an "alteration" under it. The Borough's residential application says "Project design shall conform to the 2003, International Residential Code," and Section 112-10 of the Borough Code adopts the "2006 International Building Code" and says "all future additions and revisions of the International Building Code shall be deemed to have been adopted by reference"; the Borough's pages name no other edition; this record has not read the 2003 or 2006 editions' text and does not decide which edition the Borough applies.
Permit process
Towanda Borough's code and pages read for this record do not say whether a house reroof needs a permit. Section 112-33 of the Borough Code (Article VIII, adopted May 3, 2004) says "The Uniform Construction Code, contained in 34 Pa. Code, Chapters 401-405, as amended from time to time, is hereby adopted and incorporated herein by reference as the municipal building code of this municipality," and Section 112-36 keeps in effect building code ordinances adopted on or before July 1, 1999 "which equal or exceed the requirements of the code." Section 112-37 B of the same article says "Although a permit is required, there shall be no fee for work valued at under $500." Article II of Chapter 112, a Building Code article adopted in 1969 that names the "2006 International Building Code," says in Section 112-11 B(2) that "There shall be no fee for any work that is routine maintenance and upkeep, for example, painting, siding repairs, replacing sidewalks, blowing insulation into the house, replacing roofing or any internal work, such as carpentry that does not exceed $500, provided that this does not include electrical or plumbing work." Both lines speak to fees; neither says whether a house reroof needs a permit, and this record does not decide whether it does. Chapter 325 of the Borough Code (Zoning) says in Section 325-66 A(1) that "A building and/or zoning permit shall be required prior to" "The erection, addition or alteration of any building or portion thereof"; it names no roof work and gives no relief for repairs, and this record does not decide whether a house reroof is an "alteration" under it. 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 (570-265-2696) before starting. The Borough's permit pages give office hours of Monday to Friday 7:00 a.m. to 4:00 p.m. Read for this answer: the Borough's Building / Zoning Permits, ordinances and departments pages; its residential construction permit application (five pages, scanned; pages 1 and 5 read from the rendered page images), zoning permit application, 2026 fee schedule and contractor registration letter; and on eCode360 Chapter 100 (Building Permits), Chapter 112 (Construction Codes, Uniform, in full), Chapter 122 (Contractors, Registration of), Section 325-66 of the Zoning chapter, and every page of a search of the whole Borough Code for "roof" (13 results, none a permit provision for roof work) and for "reroofing" (no results).