Georgia Residential Light Commercial Contractor Exam

Key Concepts

Footing depth, slope and over-excavation - Exterior footings shall be placed not less than 12 inches below the undisturbed ground surface; additional depth may be required for frost protection (IRC 2018, Section R403.1.4). - The bottom surface of footings shall not have a slope exceeding 1 unit vertical in 10 units horizontal; footings are stepped where elevation must change or that slope would be exceeded (IRC 2018, Section R403.1.5). Certain codes specify a maximum of 8 inches per step in stepped footings (Modern Masonry 9th ed., Ch. 15, Section 15.2.1). - If the footing site has been dug too deep, it should never be filled with soil — fill with concrete (Carpentry and Building Construction, Page 256). - Frost-protected shallow foundations: permitted where the building's monthly mean temperature is maintained at not less than 64°F; shall not be used for unheated spaces (IRC, Section R403.3). - Crushed stone footings for precast foundations:…

Key Concepts

Mixture components. Concrete is cement, coarse aggregate, fine aggregate and water in proper proportions; hydration is the chemical reaction between water and cement that generates heat and hardens the concrete — concrete does not "dry out" (Carpentry and Building Construction, Section 8.1 / Ch. 8 Hydration section). Without coarse aggregate the material is mortar or grout. Aggregates usually make up 60% to 80% of concrete volume (Modern Masonry, 18.1.2). Mixing water must be clean and free of oil, alkali or acid — use water suitable for drinking (Modern Masonry, 18.1.3).

Water-cementitious materials ratio. When SCMs are used, w/cm = weight of water ÷ total weight of all cementitious materials (portland cement, fly ash, slag, silica fume). Example given: 270 ÷ (425 + 125) = 0.49 (Contractor's Guide, p. 36).

Key Concepts

Cold-formed steel framing (Carpentry and Building Construction, Ch. 29) - Residential steel framing is categorized into three types: stick-built, panelized, and pre-engineered (Sec. 29.1, pp. 833–835). - Box header: cut a section of wall track 2" longer than the header; snip the track flanges back 1" at each end and bend the web toward the flanges with a hand seamer (Sec. 29.3, Box Header Assembly). - Punchouts: "Never punch a hole in the flange of a stud, joist, or track" — holes and punchouts reduce stud strength (Sec. 29.3, Builder's Tip – Punchouts). - Rough openings, nonload-bearing walls: allow 1½" on each side of a door opening to install wood studs; line all interior and closet door openings with wood studs (Sec. 29.3). - Rough openings, panelized walls: adding 12" of width allows two trimmer (jack) studs, one each side of the header, plus a wood stud on each side of the…

Key Concepts

Unit classification and reuse - A solid masonry unit is "one whose cross-sectional area in every plane parallel to the bearing surface is 75% or more of its gross cross-sectional area measured in the same plane." Cored bricks remain solid units as long as holes are less than 25% of the area (Modern Masonry 9th ed., p. 123). A hollow unit has less than 75% solid material in any plane. - Second-hand units shall not be reused unless they conform to the requirements of new units; whole, sound, free from cracks/defects, with old mortar cleaned off (IBC 2018 §2103.1.1). - Adobe: average compressive strength 300 psi; individual units not less than 250 psi (IBC 2018 §2109.2.1.1). - When different grades of units or mortars are combined, maximum allowable stress must not exceed that of the weakest unit, material or mortar (Modern Masonry, Ch. 8, Code Note: Combined Units).

Georgia Residential & Light Commercial Contractor Exam | 16 questions (18%)

Key Concepts

Wall framing - Sawn lumber for load-supporting purposes shall be identified by a grade mark of an accredited agency with design values certified by an accreditation body complying with DOC PS 20 (IRC R602.1.1). Wood structural panel sheathing shall conform to DOC PS 1, DOC PS 2, or (Canada) CSA O325 / CSA O437 (IRC R602.1.8). - End joints in double top plates shall be offset not less than 24 inches per IRC R602.3.2. Under IBC 2308.5.3.2, end joints in double top plates shall be offset not less than 48 inches. Know which code the question cites. - Bearing studs: where joists, trusses or rafters are spaced more than 16 inches o.c. and bearing studs below are spaced 24 inches o.c., members shall bear within 5 inches of the studs beneath (IRC R602.3.3). Exceptions: two 2×6 or two 3×4 top plates,…

Key Concepts

Minimum slopes by covering - Asphalt shingles: 2:12 or greater; from 2:12 up to 4:12, double underlayment is required (IRC 2018 R905.2.2; IBC Section 1507.2.2). - Clay and concrete tile: 2½:12 or greater (IRC R905.3.2). - Slate shingles: 4:12 or greater (IRC R905.6.2). - Wood shingles: 3:12 or greater (IRC R905.7.2). Metal roof shingles: not below 3:12 (IBC 1507.5.2). - Metal roof panels (IBC 1507.4.2): lapped, nonsoldered seam without lap sealant — 3:12 (25%); with lap sealant — ½:12 (4%); standing-seam systems — ¼:12 (2%). - Built-up roofs: ¼:12; coal-tar built-up: ⅛:12 (IBC 1507.10.1; IRC R905.9.1). - Strip shingles are installed on roofs of 4-in-12 or greater ("high slope"); lower slopes require the manufacturer's literature (Carpentry and Building Construction, Sections 22.1 and 22.2).

Key Concepts

Scope and permits - 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 (IRC 2018, Section R101.2, Page 1). - A permit application is deemed abandoned 180 days after the date of filing unless pursued in good faith or a permit has been issued (IRC 2018, Section R105.3.2, Page 5). - Permit exemptions include fences not over 7 feet high; a shed over the 200 sq ft limit, a retaining wall over the 4-foot limit, and attached decks serving an exit door are not exempt (IRC 2018, Section R105.2, Pages 3–4). - The certificate of occupancy must contain the type of construction as defined in Chapter 6 (listed as item 9). Contractor license number, estimated cost and architect's seal number are not among the listed items (IBC 2018, Section 111.2, Page 9).

Key Concepts

Panel types and selection - Type-X fire-code drywall is 5/8" thick and contains glass fibers that prevent crumbling in extreme heat; Type-C is even more fire resistant and contains vermiculite (Carpentry and Building Construction, Ch. 32, Fire-Code Drywall). - Glass-mat gypsum board ("paperless drywall") has fiberglass front and back surfaces and is approved for shower stalls and tub/shower surrounds; green board is no longer permitted there except on ceiling surfaces (Ch. 32, Moisture-Resistant Drywall). IRC Table R702.4.2 lists glass mat gypsum backing panel (ASTM C1178) as an approved tile backer. - Long edges are tapered so joints can be filled and smoothed flush (Ch. 32, Standard Drywall).

Key Concepts

Fall protection (Subpart M) - Each employee engaged in residential construction activities 6 feet or more above lower levels must be protected by guardrail systems, scaffolding, a safety net system, or a personal fall arrest system — §1926.501(b)(13) (also BCSI B11 Fall Protection & Trusses, Page 89). - Each employee on a walking/working surface with an unprotected side or edge 6 feet (1.8 m) or more above a lower level must be protected by guardrail, safety net, or personal fall arrest systems — §1926.501(b)(1). - Top edge height of top rails: 42 inches (1.1 m) plus or minus 3 inches (8 cm) above the walking/working level — §1926.502(b)(1) (stated elsewhere in the SOURCE as a 39–45" range). - Top rails must withstand, without failure, a force of at least 200 pounds (890 N) applied within 2 inches of the top edge, in any outward or downward direction, at any point along the…