ICC G14 Roofing Contractor Exam (2018 IBC/IRC/IPC)

Roofing Contractor Exam — 2018 International Building Code and 2018 International Residential Code

Key Concepts

Scope and applicability - Detached one- and two-family dwellings and townhouses not more than three stories above grade plane with a separate means of egress, and their accessory structures not more than three stories above grade plane, may comply with either the IBC or the IRC (IBC 101.2 Exception; IRC R101.2). - Appendix provisions do not apply unless specifically adopted (IBC 101.2.1); the IRC counterpart requires them to be specifically referenced in the adopting ordinance (IRC R102.5). - Existing structures/premises, light, ventilation, sanitation and life/fire safety hazards → International Property Maintenance Code (IBC 101.4.4); repair, alteration, change of occupancy, addition, relocation → IEBC (IBC 101.4.7). - Additions, alterations or repairs shall conform to the requirements for a new structure, without requiring the existing structure to comply (IRC R102.7.1).

Permits - Exempt (IRC R105.2, Building item 1): one-story detached accessory structures where floor area does not exceed 200 square feet (the IBC 105.2 threshold for structures regulated by the Building Code is 120 square feet). - Exempt (IBC 105.2, Building item 2): fences not over 7 feet high. Item 12: Group R-3/U window awnings supported by an exterior wall, not projecting more than 54 inches, and requiring no additional support — all three conditions. - No permit for utility generation, transmission, distribution or metering equipment under public service agency ownership and control by established right (IBC 105.2.2). - Annual permit only for alterations to an already approved electrical, gas, mechanical or plumbing installation (IBC 105.1.1); detailed records required (IBC 105.1.2). - Application abandoned 180 days after filing; extensions not exceeding 90 days each (IBC 105.3.2) — the IRC counterpart R105.3.2 allows 180-day extensions. - Permit invalid if work not commenced within 180 days or suspended/abandoned 180 days; extensions of not more than 180 days each (IBC 105.5). - Temporary structures/uses: not more than 180 days (IRC R107.1); temporary power may be allowed before the final certificate of completion (IRC R107.3, NFPA 70). - IBC 105.3 application contents do not include an anticipated completion date.

Key Concepts

Fire classification. Class A, B or C roofing is required in jurisdictions designated by law or where the roof edge is less than 3 feet from a lot line (IRC R902.1). Class A assemblies include slate installed over underlayment over combustible decks (R902.1 Exc. 4); metal sheets/shingles, clay or concrete tile and slate qualify only on noncombustible decks (Exc. 2); copper sheets must be not less than 16 ounces per square foot over combustible decks (Exc. 3; IBC 1505.2 Exc. 3). Fire-retardant-treated shakes and shingles are treated by impregnation using the full-cell vacuum-pressure process per AWPA C1 (IBC 1505.6). Special purpose wood shake/shingle roofs require 5/8-inch Type X water-resistant gypsum backing board or gypsum sheathing under the sheathing (IBC 1505.7). Rooftop rack-mounted PV panel systems: tested, listed and identified per UL 1703 and UL 2703 (IBC 1505.9).

Underlayment and ice barriers. Ice barrier extends from the lowest edges of all roof surfaces to not less than 24 inches inside the exterior wall line (IBC 1507.1.2); on slopes 8:12 or greater it must also extend not less than 36 inches measured along the roof slope from the eave edge (IRC R905.1.2). Cap nail shanks: not less than 0.083 inch (ring shank), 0.091 inch (smooth shank) — IRC R905.1.1 Item 3.4/Table R905.1.1(3). The 4-inch-wide self-adhering membrane strip over deck joints is limited to ultimate design wind speeds less than 140 mph (R905.1.1 Exc. 2). BIPV underlayment where Vasd exceeds 110 mph: fastened along the overlap at not more than 36 inches o.c. (IBC 1507.18.4.1).

Key Concepts

Secondary (emergency overflow) drainage — when required. Where roof drains are required, secondary drains or scuppers are required where the roof perimeter construction extends above the roof so water will be entrapped if the primary drains allow buildup for any reason (IBC 1502.2; IRC R903.4.1; IPC 1108.1). Installation and sizing follow IPC Sections 1106 and 1108.

Scupper minimums. Scuppers used for secondary drainage shall not have an opening dimension of less than 4 inches (102 mm), and the flow through the primary system shall not be considered when locating and sizing scuppers (IBC 1502.3). IPC 1106.5 and 1108.3 add that the opening width shall equal or exceed the circumference of a roof drain sized for the same roof area.

IRC overflow arrangement. Overflow drains the same size as the roof drains are set with the inlet flow line 2 inches above the low point of the roof; overflow scuppers shall have three times the size of the roof drains, a minimum opening height of 4 inches, and inlet flow 2 inches above the low point of the roof served. Overflow drains discharge to an approved location and shall not be connected to roof drain lines (IRC R903.4.1).

IPC drainage details. Single-assembly primary/secondary drains must have independent inlet and outlet for each drain (1108.1); secondary systems discharge separately, above grade (1108.2); roof drains conform to ASME A112.6.4 or ASME A112.3.1 (1102.6), while siphonic drains follow ASME A112.6.9 and ASPE 45 (1107.1); leaders/storm drains connected to a combined sewer must be trapped, by an individual trap per conductor branch or one trap in the main storm drain just before the combined connection (1103.1).

Gutters. Gutters and leaders on the outside of buildings other than Group R-3, private garages and Type V construction shall be noncombustible or not less than Schedule 40 plastic pipe (IBC 1502.4).

2018 IRC Chapter 9 (R908) and 2018 IBC Chapter 15 (1511)

Key Concepts

Scope and general rule (IRC R908.1). Materials and methods of application used for re-covering or replacing an existing roof covering shall comply with the requirements of Chapter 9 (Roof Assemblies) — not Chapter 8, which governs roof-ceiling framing (R801.1). Underlayment and all other Chapter 9 provisions still apply to reroofing work.

Two reroofing exceptions, both tied to positive roof drainage. - IRC R908.1, Exception 1 / IBC 1511.1, Exception 1: reroofing is not required to meet the minimum design slope of one-quarter unit vertical in 12 units horizontal (2-percent slope) of R905 / Section 1507 where the roof provides positive roof drainage. If the roof ponds and does not drain positively, the 1/4:12 minimum applies. - IRC R908.1, Exception 2: re-covering or replacing an existing roof covering shall not require the secondary (emergency overflow) drains or scuppers of R903.4.1 to be added to an existing roof that provides positive drainage.

Roof replacement (IRC R908.3 / IBC 1511.3). All existing layers of roof covering are removed down to the roof deck. Exception: where the existing roof assembly includes an ice barrier membrane adhered to the roof deck, it may remain in place and be covered with an additional layer of ice barrier membrane installed per R905 (IRC) / Section 1507 (IBC). No other underlayment, base sheet or insulation gets this allowance.

Roof recover permitted (IRC R908.3.1 / IBC 1511.3.1). - Item 2: complete and separate roofing systems, such as standing-seam metal roof systems, that are designed to transmit the roof loads directly to the building's structural system and do not rely on existing roofs and roof coverings for support. - Item 3: metal panel, metal shingle, and concrete and clay tile coverings over existing wood shake roofs, applied per R908.4 / 1511.4. - Item 4: a new protective roof coating over an existing protective roof coating, metal roof panel, metal roof shingle, mineral-surfaced roll roofing, built-up roof, modified bitumen roofing, thermoset and thermoplastic single-ply roofing, or spray polyurethane foam roofing.