Tennessee BC Combined Residential/Commercial/Industrial Contractor

Tennessee BC Combined – Residential/Commercial/Industrial Contractor Exam Study Brief

Key Concepts

Excavation Safety – OSHA 29 CFR 1926 Subpart P

• Scope (§1926.650): Applies to ALL open excavations, including trenches. A trench is a narrow excavation where depth > width, and width at the bottom ≤ 15 feet.
• Competent Person: Must be on-site and capable of identifying hazards AND authorized to take corrective action. Required before any worker enters an excavation.
• Protective systems required for excavations 5 feet or deeper (or shallower if a competent person determines a hazard exists). Options include:
• Sloping – sides cut back at a safe angle
• Shoring – hydraulic, mechanical, or timber systems supporting trench walls
• Shielding – trench boxes/shields that protect workers inside
• Cave-in protection required at 5 ft depth. At 20 ft or deeper, a registered professional engineer (RPE) must design the protective system.
• Access/egress: Ladders, steps,…

Key Concepts

Concrete Basics

• Concrete is a mixture of portland cement, aggregate (fine and coarse), water, and admixtures. The water-cement (w/c) ratio is the single most important factor controlling strength and durability — lower w/c = higher strength.
• Five basic types of portland cement: Type I (general use), Type II (moderate sulfate resistance), Type III (high early strength), Type IV (low heat), Type V (high sulfate resistance).
• Concrete gains strength through hydration, not drying — which is why curing (maintaining moisture and temperature) is critical.

Concrete Mix Design & Proportioning

• Mix design is expressed as a ratio of cement:fine aggregate:coarse aggregate by weight (e.g., 1:2:3).
• Target compressive strength (f'c) is specified at 28 days. Design strength must exceed specified strength by a margin to account for variability.
• Slump measures workability — higher slump = more water = lower strength. Do not add water to restore slump…

Key Concepts

Masonry Materials

• Clay brick: Classified by grades (SW, MW, NW) based on weathering resistance. SW = severe weathering, used below grade or exposed.
• CMU (Concrete Masonry Units): Standard nominal size 8"×8"×16"; actual size is 3/8" smaller to account for mortar joint. Hollow, solid, or grouted configurations.
• AAC (Autoclaved Aerated Concrete): Lightweight, high thermal resistance, low strength relative to standard CMU; requires specialty mortar (thin-bed).
• Stone: Rubble, ashlar, or cut stone; used structurally or as veneer; natural variability requires engineering judgment.

Mortar Types (ASTM C270 / TMS 402)

6 questions | 6% of exam

Key Concepts

Wood Wall Framing Components

• Bottom plate (sole plate): Anchors wall to floor; doubled top plate ties walls together and laps at corners
• Studs: Typically 2×4 at 16" o.c. or 2×6 at 24" o.c.; standard wall height uses precut studs (92⅝" for 8' walls)
• Headers: Carry load above openings; sized by span and load; double 2× members with ½" spacer (to match wall width) or engineered lumber (LVL)
• King studs, trimmer (jack) studs, cripple studs: King runs full height; trimmer supports header; cripples fill above header and below rough sill
• Rough sill: Bottom of window rough opening; supported by cripple studs below

(10 questions, 10% of exam)

Key Concepts

Steel Joist Types and Designations (SJI Standards)

• K-Series: Short-span joists, spans up to 60 ft. Designation example: 18K6 = 18" depth, K-Series, chord size 6.
• LH-Series (Longspan): Spans 25–96 ft. Used for longer roof/floor spans.
• DLH-Series (Deep Longspan): Spans 89–144 ft. Deeper than LH, for very long spans.
• Joist Girders: Primary framing members that support K, LH, or DLH joists. Designation includes span, number of joist spaces, and load (e.g., 48G8N14K).
• CJ-Series Composite Joists: Work with concrete slabs and shear connectors for composite action in floor systems.

Erection Bridging and Hoisting Cable Release (OSHA 29 CFR 1926.757)

• Hoisting cables cannot be released until the erection bridging is completely installed and anchored, and the joist is bolted at both ends.
• For K-Series joists ≤ 60 ft: one row of erection bridging required before hoisting cable release.
• For…

Key Concepts

Roof Framing Types & Components

• Gable roof: Two sloping sides, triangular ends (gable); simplest and most common
• Hip roof: All four sides slope downward; stronger in high-wind/storm regions; no vertical gable ends
• Valley: Interior angle where two roof slopes meet; requires valley rafters and special flashing
• Shed (lean-to): Single slope; simplest framing
• Gambrel: Two slopes per side (barn-style); steeper lower slope, shallower upper
• Mansard: Four sides, each with two slopes; lower slope nearly vertical; allows usable attic space
• Dutch hip: Combination of gable and hip; gable at top, hip at eaves

Rafter Components & Terminology

• Span: Total width of building from outside wall to outside wall
• Total run: Half the span (for common rafters on a symmetrical roof)
• Unit run: 12" (standard horizontal reference unit)
• Total rise: Vertical height from top plate to ridge
• Unit rise: Rise per…

Tennessee BC Combined Residential/Commercial/Industrial Contractor 10 questions | 10% of exam

Key Concepts

Gypsum Board & Drywall

• Types: Standard (1/2" most common), fire-rated (Type X, 5/8"), moisture-resistant (green board), abuse-resistant
• Framing spacing: 16" or 24" OC for walls; ceilings typically require 12" OC for 3/8" board, 16" OC for 1/2"
• Fastening: Screws preferred over nails; minimum edge distance 3/8"; screws must penetrate framing min. 5/8" (wood)
• Finishing Levels (0–5): Level 0 = no finish; Level 1 = taped joints only (above ceilings, fire barriers); Level 3 = primer + one coat (texture walls); Level 5 = skim coat (critical lighting applications, gloss paint)

Plumbing Systems

• Supply: Cold/hot distribution; water pressure typically 40–80 psi residential
• DWV (Drain-Waste-Vent): Must maintain trap seals 2"–4" water; P-traps required at every fixture
• Trap rules: Every fixture needs a trap; no double-trapping; max trap-to-vent distance varies by pipe size (e.g.,…

Tennessee BC Combined Residential/Commercial/Industrial Contractor Exam

Key Concepts

Occupancy Classification & Use Groups (IBC Chapter 3)

• IBC Chapter 3 defines 10 primary occupancy groups: A (Assembly), B (Business), E (Educational), F (Factory), H (High Hazard), I (Institutional), M (Mercantile), R (Residential), S (Storage), U (Utility/Miscellaneous).
• Mixed occupancies must comply with IBC Section 508: separated, non-separated, or accessory occupancy provisions apply.
• Accessory occupancies (508.2): must be ≤10% of the floor area of the story and not exceed the tabular area limits.

Building Height, Area & Type of Construction (IBC Chapters 5 & 6)

• IBC Table 503 controls allowable building height (in feet and stories) and floor area per story based on occupancy group + construction type.
• Construction types (IBC Chapter 6): Type I (highest fire resistance) through Type V (least). Types I and II use noncombustible materials; Types III, IV, V may use combustible elements. -…

29 CFR 1926 | 6 Questions | 6% of Exam

Key Concepts

Fall Protection (Subpart M – §1926.500–503)

• Fall protection required at 6 feet in construction (not 4 ft as in general industry)
• Three accepted systems: guardrail, safety net, personal fall arrest system (PFAS)
• Guardrail top rail: 42 inches (±3 in) high; mid-rail at 21 inches; withstand 200 lbs force
• PFAS components: harness, lanyard, anchor — anchor must support 5,000 lbs per worker
• PFAS must limit free fall to 6 feet and arrest force to 1,800 lbs
• Safety nets installed within 30 feet below work surface

Scaffolding (Subpart L – §1926.450–454)

• Scaffolds must support 4× intended load
• Fall protection required when platform is 10 feet or more above lower level
• Guardrails OR PFAS required at 10 ft; both may be required on certain scaffold types
• Must be erected/dismantled under supervision of…