Tennessee BC-b Small Commercial Contractor

Tennessee BC-b Small Commercial Contractor Exam — 9% of Exam (6 Questions)

Key Concepts

Soil Classification & Bearing Capacity

• Bearing capacity = soil's ability to support weight without excessive settlement
• Strongest soils: Compacted gravel mixed with sand or clay (hardpan) — best for most foundations
• Good soils: Compacted loam (sand and silt) of considerable depth
• Unreliable soils: Clay (firm when dry, expands and weakens when wet); marshy/quick soils require pile foundations
• Acceptable: Dry sand, or wet sand when confined; avoid porous sandy soils near running water
• Soil conditions vary across a single site — never assume uniformity

Geotechnical Investigations

• Open test pits: Best for shallow exploration; allow visual inspection of soil layers and field testing
• Power augers/drilling rigs: Required for deep excavation and major foundation systems; also locate the water table elevation
• Fill sites: Always determine quality of fill material AND…

Tennessee BC-b Small Commercial Contractor Exam Study Brief

Key Concepts

Concrete Mixture Proportioning - Four critical field control tests: slump, air content, compressive strength, and yield (ASTM standards govern each) - Sampling governed by ASTM C172/C172M — sample from the middle of the truck, never first or last discharge - Slump measured per ASTM C143/C143M — indicates consistency, workability, and batch uniformity - All field testing should be performed by an ACI Concrete Field Testing Technician, Grade I or equivalent - Companion cylinders cast by the contractor verify strength development and guide safe formwork removal timing

Durability & Exposure Classifications - Mix design must address specific exposure conditions: freezing/thawing, sulfate exposure, chloride (corrosion), and low-permeability requirements - Water-to-cementitious materials ratio (w/cm) is the primary lever for durability — lower w/cm = greater durability - Air entrainment is required for freeze-thaw exposure; air content targets vary by aggregate size and exposure severity

Key Concepts

Mortar Types (ASTM C270)

Memorize this sequence — M, S, N, O, K — from strongest to weakest compressive strength:

Proportioning (ASTM C270): Type S = 1 part portland cement, ½ part lime, 4.5 parts sand. Type N = 1 part portland, 1 part lime, 6 parts sand. More lime = more workability but less strength.

12 questions | 17% of exam

Key Concepts

Steel Joist Series (SJI Designations)

• K-Series: Shallow, short-span joists (8"–30" depth); used for light roof and floor loads; spans up to ~60 ft
• LH-Series (Longspan): Depths 18"–48"; spans up to 96 ft; roof and floor applications
• DLH-Series (Deep Longspan): Depths 52"–72"; spans up to 144 ft; large-bay structures
• Joist Girders: Primary structural members that support K, LH, or DLH joists; designated by depth, number of joist spaces, and end reaction (e.g., 40G8N11K)
• CJ-Series (Composite Joists): Work compositely with concrete slab via shear connectors; used for floor systems

Steel Deck Types

• Composite Floor Deck: Embossed/fluted profile; bonds with concrete slab; shear studs transfer load
• Form Deck: Non-composite; acts only as concrete formwork; no structural composite action
• Roof Deck: Narrower flutes (1.5" typical); supports roofing only — not designed for concrete fill loads
• Cellular Deck: Two-sheet…

Key Concepts

Wall Framing Components

• Bottom plate (sole plate): Single 2x plate nailed to subfloor; top plates are doubled (double top plate) to transfer loads and tie corners.
• Studs: Typically 2×4 or 2×6, spaced 16" or 24" o.c. for load-bearing walls.
• Headers: Carry loads over rough openings. Size increases with span. Common sizes: 4×6 for up to 4', 4×10 or doubled 2×10 for wider spans. Must be supported by jack studs (trimmers) and king studs.
• Rough opening (RO): Door RO = door size + 2" (width) + 2½" (height) to allow for frame, shimming. Window RO similar.
• Cripple studs: Short studs above headers and below rough sill.

Key Concepts

Roof Slope

• Slope = rise over run, expressed as X:12 (e.g., 4:12 means 4" rise per 12" horizontal run)
• Low slope: less than 2:12; steep slope: 4:12 and above; moderate: 2:12 to 4:12
• Slope determines underlayment type, shingle applicability, and material restrictions

Roof Framing Components

• Ridge board: horizontal member at the peak where rafters meet
• Common rafters: run perpendicular from ridge to top plate
• Hip rafters: run diagonally from ridge corners to building corners
• Valley rafters: run diagonally at interior roof intersections
• Jack rafters: shorter rafters that run from hip/valley rafter to plate or ridge

Tennessee BC-b Small Commercial Contractor Exam (5 Questions, 7%)

Key Concepts

Gypsum Board Types & Selection

• Standard drywall (ASTM C1396): Available in 1/4", 3/8", 1/2", 5/8" thicknesses. 5/8" is standard for commercial fire-rated assemblies.
• Type X (Firecode): Enhanced fire resistance via glass fibers; required in fire-rated assemblies. 5/8" Type X is most common in commercial applications.
• Moisture-resistant (MR/greenboard): Not a substitute for cement board in wet areas; suitable only for areas with intermittent humidity.
• Mold-resistant board: Fiberglass-faced or treated core; appropriate for high-humidity environments.
• Cement board / backerboard (Durock, ASTM C1325): Required behind tile in showers, tub surrounds, and wet areas. Not a structural panel — must be installed over proper framing.

Key Concepts

Fall Protection (29 CFR 1926 Subpart M)

• Fall protection required at 6 feet above lower level for construction (not 4 ft — that's 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 of force
• Safety nets must be installed within 30 feet below the work surface
• PFAS components: anchor, body harness, lanyard/deceleration device — must limit free fall to 6 feet and arrest force to 1,800 lbs

Scaffolding (29 CFR 1926 Subpart L)

• Scaffolds must support 4x the intended load (safety factor)
• Guardrails required when working surface is 10 feet or more above lower level
• Scaffold platforms must be at least 18 inches wide
• Competent person must inspect scaffold before each work shift
• Workers must be trained by a qualified person…

Tennessee BC-b Small Commercial Contractor — 15 Questions (21% of Exam)

Key Concepts

Occupancy Classification & Building Use Groups (IBC)

• IBC Chapter 3 defines use groups: A (Assembly), B (Business), E (Educational), F (Factory), H (Hazardous), I (Institutional), M (Mercantile), R (Residential), S (Storage), U (Utility).
• Mixed-occupancy buildings require nonseparated or separated occupancy analysis — separated requires fire-rated walls between groups.
• Correct classification drives nearly every other code requirement: height, area, egress, sprinklers.

Types of Construction & Fire-Resistance Ratings (IBC Chapter 6)

• Type I: Noncombustible, highest fire resistance (IA > IB). Structural elements rated 3–4 hours.
• Type II: Noncombustible, lower ratings than Type I (IIA = 1 hr; IIB = 0 hr).
• Type III: Noncombustible exterior walls, combustible interior framing.
• Type IV: Heavy timber — minimum member sizes substitute for fire ratings.
• Type V: Combustible throughout (VA = 1 hr; VB =…