ICC G13 Residential Building Contractor (C) Exam (2018 IRC)

Key Concepts

Scope and applicability - The IRC applies to detached one- and two-family dwellings and townhouses not more than three stories above grade plane in height with a separate means of egress, and their accessory structures not more than three stories above grade plane (R101.2). - Exception 2 to R101.2: owner-occupied lodging houses with five or fewer guestrooms may be built under the IRC when provided with a residential fire sprinkler system complying with Section P2904. - Where a general and a specific requirement conflict, the specific requirement applies; where different sections specify different requirements, the most restrictive governs (R102.1). - Appendix provisions do not apply unless specifically referenced in the adopting ordinance (R102.5). - Legal occupancy existing on the date of adoption may continue except as covered in this code, the International Property Maintenance Code or International Fire Code, or as deemed necessary by the building official for general safety and welfare (R102.7).

Permits (R105) - Permit application must, among seven listed items, state the valuation of the proposed work (R105.3, item 5). - Flood hazard areas: work is a substantial improvement when its value equals or exceeds 50 percent of the market value of the building before the damage occurred or the improvement is started; existing portions must then meet R322 (R105.3.1.1). - An application is deemed abandoned 180 days after filing unless pursued in good faith or a permit has been issued; extensions of not more than 180 days each may be granted (R105.3.2). - A permit becomes invalid unless work is commenced within 180 days after issuance, or if more than 180 days pass between inspections; written extensions of not more than 180 days each (R105.5). - Temporary structures/uses: permits are limited as to time of service and shall not be permitted for more than 180 days; extensions for demonstrated cause (R107.1); the building official may terminate the permit (R107.4).

Key Concepts

Exterior walls and fire separation distance (R302.1, Tables R302.1(1) and R302.1(2)) - Unsprinklered dwellings — Table R302.1(1): openings in exterior walls are not allowed at less than 3 feet, limited to 25 percent maximum of wall area from 3 feet to less than 5 feet, and unlimited at 5 feet and greater (0 hours). - Sprinklered dwellings — Table R302.1(2): exterior walls are permitted to be not fire-resistance rated at a fire separation distance of 3 feet or greater; openings are unlimited (0 hours) at 3 feet. - Exception 4: detached garages accessory to a dwelling located within 2 feet of a lot line are permitted roof eave projections not exceeding 4 inches.

Separations (R302.2.2, R302.3, R302.5.1, R302.6, R302.7) - Townhouse common wall: not less than 1-hour where a sprinkler system per Section P2904 is provided (Item 1); not less than 2-hour where no sprinkler system is provided (Item 2). - Two-family dwellings: wall and floor assemblies not less than 1-hour (ASTM E119, UL 263 or IBC Section 703.3). Exception 1 permits 1/2 hour in buildings equipped throughout with an automatic sprinkler system installed in accordance with NFPA 13. - Garage-to-dwelling openings: solid wood doors not less than 1-3/8 inches thick, solid or honeycomb-core steel doors not less than 1-3/8 inches, or 20-minute fire-rated doors, each with a self-closing or automatic-closing device. Openings directly into a sleeping room are not permitted. - Table R302.6: separation from the residence and attics is not less than 1/2-inch gypsum board applied to the garage side. - Under-stair protection: enclosed space under stairs accessed by a door or access panel shall be protected on the enclosed side with 1/2-inch gypsum board.

Key Concepts

Footings & Foundations - Presumptive load-bearing values (Table R401.4.1): crystalline bedrock 12,000 psf; sedimentary and foliated rock 4,000 psf; sandy gravel and/or gravel (GW and GP) 3,000 psf; sand/silty sand 2,000 psf. - Grade shall fall not fewer than 6 inches within the first 10 feet from foundation walls (R401.3). - Exterior footings: not less than 12 inches below undisturbed ground surface (R403.1.4). - Footing bottom slope shall not exceed 1 unit vertical in 10 horizontal; step footings where exceeded (R403.1.5). - Footing projections, P: not less than 2 inches, not exceeding the thickness of the footing (R403.1.1). - Frost-protected shallow foundations: permitted where monthly mean temperature is maintained at not less than 64°F; not for unheated spaces (R403.3). - Crushed stone footings for precast foundations: consolidate with vibratory plate in not greater than 8-inch lifts (R403.4.1). - Anchor bolts: spaced not greater than 6 feet on center; not fewer than two bolts per plate section, one not more than 12 inches from each end (R403.1.6). - Concrete cast against earth: minimum 3 inches cover over steel reinforcement (R403.1.3.5.3; R404.1.3.3.7.4). - Foundation walls shall extend above finished grade not less than 4 inches where masonry veneer is used, not less than 6 inches elsewhere (R404.1.6). - Backfill bracing exception: not required for walls supporting less than 4 feet of unbalanced backfill (R404.1.7). - Foundation drains: tile/perforated pipe on not less than 2 inches washed gravel or crushed rock, covered with not less than 6 inches of same (R405.1). Drainage system not required on well-drained ground or sand-gravel mixture (Group I) soils (R405.1 Exception, Table R405.1). - Wood foundation basements: porous gravel/crushed stone/coarse sand layer minimum 4 inches under basement floor (R405.2.1). - Crawl space grade may be at bottom of footings unless groundwater can rise to within 6 inches of finished floor at the perimeter (R408.6).

2018 IRC

Key Concepts

Roof covering minimum slopes & deck requirements - Asphalt shingles: slopes of 2:12 or greater; from 2:12 up to 4:12 double underlayment is required (R905.2.2). Shingles must be fastened to solidly sheathed decks (R905.2.1). - Clay and concrete tile: 2½:12 or greater (R905.3.2); installed only over solid sheathing or spaced structural sheathing boards (R905.3.1). - Wood shingles and wood shakes: 3:12 or greater (R905.7.2, R905.8.2). Wood shingles may go on solid or spaced sheathing; spaced boards not less than 1-inch by 4-inch nominal, spaced on centers equal to the weather exposure (R905.7.1). - Standing-seam metal roof systems: minimum ¼:12 (R905.10.2). Lapped, nonsoldered-seam metal roofs: ½:12 with applied lap sealant, 3:12 without lap sealant.

Underlayment & ice barriers - Asphalt shingles, 2:12 up to 4:12: two layers — a 19-inch starting strip at the eave, then 36-inch-wide sheets overlapping successive sheets 19 inches (Table R905.1.1(2)). - Ice barrier: extends from the lowest edges of all roof surfaces to a point not less than 24 inches inside the exterior wall line; on slopes equal to or greater than 8:12 it shall also be applied not less than 36 inches measured along the roof slope from the eave edge (R905.1.2).

Fasteners and flashing - Asphalt shingle fasteners: minimum 12-gage (0.105 inch) shank, minimum 3/8-inch-diameter head, long enough to penetrate the roofing and not less than 3/4 inch into the roof sheathing (R905.2.5). - Wood shingles: two fasteners per shingle (R905.7.5). - Metal flashing at wall/roof intersections, changes in slope or direction, and roof openings: corrosion resistant, not less than 0.019 inch (No. 26 galvanized sheet) (R903.2.1). - Cricket or saddle required on the ridge side of any chimney or penetration more than 30 inches wide, measured perpendicular to the slope (R903.2.2). - Sidewall base flashing (continuous or step): not less than 4 inches in height and 4 inches in width (R905.2.8.3). - Drip edge: extends not less than 1/4 inch below the roof sheathing and not less than 2 inches up back onto the roof deck; fastened at not more than 12 inches o.c.; underlayment goes over the…