Alabama Home Builder Skill Exam

Key Concepts

Types of Construction Drawings

• Plan view (floor plan): A top-down, bird's-eye view showing room layout, wall locations, doors, and windows. The most referenced drawing on a job site.
• Elevations: Exterior or interior vertical views showing heights, window/door placement, rooflines, and finish materials. Labeled by compass direction (North, South, East, West).
• Sections: A cut-through view revealing interior construction — wall assemblies, floor/ceiling heights, footing depths, and structural details.
• Detail drawings: Large-scale close-ups of specific connections or assemblies (e.g., stair tread nosing, flashing, window sill). Used when standard drawings lack sufficient clarity.
• Site/plot plans: Show the lot boundaries, property lines, building footprint, setbacks, easements, utilities, and north arrow. Required for permit applications.

Key Concepts

Footing Design & Reinforcement (IRC R403)

• Footings must bear on undisturbed natural soil or engineered fill with adequate bearing capacity
• Minimum footing width = wall thickness + 2x projection on each side; depth must be below frost line
• IRC R403.1 requires continuous footings under all bearing walls; minimum 6" thick
• Reinforcement: typically two #4 rebar horizontal in footings; vertical dowels tie footing to foundation wall
• Soil bearing value assumed at 1,500 psf (pounds per square foot) for most residential design unless soil testing indicates otherwise

Foundation Wall Types

• Poured concrete: strongest in compression; requires formed walls; must cure properly before backfill
• CMU (Concrete Masonry Unit): modular block; cores filled and reinforced per IRC R606; requires mortar joints and may need pilasters for long spans
• **ICF (Insulating…

Key Concepts

Concrete Mix Design

• Concrete = Portland cement + fine aggregate (sand) + coarse aggregate (gravel/crushed stone) + water. All four must be present — remove coarse aggregate and you have mortar or grout, not concrete.
• Hydration is the chemical reaction between cement and water that causes hardening; it generates heat as concrete cures.
• Water-cement ratio: Lower ratio = higher strength. Excess water weakens concrete. Never add water to increase workability without accepting a strength penalty.
• Slump test measures concrete workability/consistency. Higher slump = wetter mix = easier to place but lower strength.
• Aggregate sizing affects workability and strength; maximum aggregate size should not exceed 1/3 the slab depth, 3/4 the clear spacing between rebar, or 1/5 the narrowest form dimension.

Key Concepts

Brick Types, Grades & ASTM Classifications

• ASTM C62 – Building brick (structural). Three grades: SW (Severe Weathering), MW (Moderate Weathering), NW (Negligible Weathering).
• ASTM C216 – Face brick (appearance matters). Grades SW and MW only. Types FBS (standard), FBX (tight tolerances), FBA (non-uniform/architectural).
• ASTM C652 – Hollow brick. Same SW/MW grades; must meet minimum shell and web thicknesses.
• Use SW grade whenever brick is exposed to freezing/thawing or in contact with the ground.

Mortar Types, Composition & Mixing

• Type M – Highest strength (2,500 psi); below grade, foundations, retaining walls.
• Type S – High strength (1,800 psi); at or below grade, exterior walls, good bond with reinforced masonry. Most common for residential.
• Type N – Medium strength (750 psi); above-grade exterior, chimneys, veneers. General-purpose residential choice.
• **Type…

Key Concepts

Wood Properties & Species Selection

• Hardwoods come from deciduous (broad-leaved) trees; softwoods come from coniferous (needle/cone-bearing) trees. These terms describe tree type, not actual hardness.
• Common framing softwoods: Douglas fir, Southern yellow pine, hem-fir, spruce-pine-fir (SPF). These dominate structural applications due to strength-to-weight ratio.
• Moisture Content (MC): Lumber must be dried to acceptable MC before use. "Dry" lumber is ≤19% MC; engineered and finish applications require ≤15%. Excess MC causes shrinkage, warping, and fastener loosening after installation.
• Fiber-saturation point (~28–30% MC) is the threshold below which wood begins to shrink as it dries.
• Lumber grades are stamped on each piece. The grade stamp includes: species, grade, mill number, moisture content designation (S-DRY, S-GRN), and certifying agency. Higher grade = fewer defects = greater allowable stress.
• Common defects: warp (bow, cup,…

Key Concepts

Roof Slope Classification

• Low slope: less than 2:12
• Conventional slope: 2:12 to 4:12
• Steep slope: 4:12 and above
• Slope is expressed as rise (inches) per 12 inches of run

Minimum Slope Requirements by Material (IRC)

Underlayment Requirements (IRC R905)

• Asphalt shingles (4:12+): Single layer #15 felt
• Asphalt shingles (2:12–4:12): Double layer #15 felt, lapped 19" with 17" exposure, or a single layer of #30 felt
• Wood shakes: Interlayment…

4 questions | 5% of exam

Key Concepts

Gypsum Wallboard (Drywall)

• Standard sizes: 4×8, 4×10, 4×12 sheets; thicknesses: 1/4", 3/8", 1/2" (most common for walls), 5/8" (Type X fire-rated)
• Types: Regular, moisture-resistant (green board — bathrooms/kitchens), fire-rated Type X (garages, furnace rooms), abuse-resistant, flexible (1/4" for curves)
• Installation: Perpendicular application to framing is stronger than parallel; fasten with screws or nails; dimple fasteners slightly below surface without breaking paper
• Ceiling: 5/8" recommended to resist sag; maximum framing spacing 16" o.c. for 1/2", 24" o.c. only with 5/8"

Drywall Finishing Levels (0–5)

• Level 0: No finishing (temporary)
• Level 1: Tape embedded in joint compound (fire-rated assemblies, attics)
• Level 2: Level 1 + skim coat over tape and fasteners (tile substrate)
• Level 3: Level 2 + one additional coat (texture…

Key Concepts

Water-Resistive Barriers & Housewrap

• Housewrap (WRB) must be installed behind all exterior cladding to prevent moisture intrusion while allowing vapor to escape
• Lap upper courses over lower courses (shingle fashion) — minimum 6" horizontal laps, 12" vertical laps
• Install before windows and doors; flash all penetrations over the WRB
• Tape all seams; staple or cap-nail to studs

Exterior Flashing Requirements

• Flashing is required at: window and door heads, sills, wall-to-roof intersections, deck ledgers, and all horizontal surface transitions
• Head flashing always laps over WRB; sill flashing always goes under WRB
• Use corrosion-resistant metal (aluminum, galvanized steel, or copper) or approved self-adhering membrane flashing

Key Concepts

Plumbing System Components & Pipe Materials

• Supply piping: Copper (Types K, L, M — K is heaviest wall, M is lightest), CPVC, PEX (cross-linked polyethylene). PEX is flexible and freeze-resistant; widely used in residential supply.
• DWV (Drain-Waste-Vent): ABS (black), PVC (white), or cast iron. Drain pipes must slope ¼" per foot minimum toward the drain.
• Traps: Every fixture requires a trap to block sewer gases. P-traps are standard. Drum traps are generally prohibited under modern codes.
• Venting: DWV systems require venting to atmosphere to maintain trap seals and allow drainage flow.

Key Concepts

Fall Protection (6-Foot Rule) OSHA requires fall protection for construction workers at heights of 6 feet or more above a lower level. Acceptable systems include guardrail systems, safety net systems, and personal fall arrest systems (PFAS). The 6-foot rule applies to residential construction specifically — do not confuse with the 4-foot rule used in general industry.

Scaffold Safety - Scaffolds must support at least 4 times the maximum intended load - Guardrails required on scaffolds 10 feet or higher - Scaffold planks must extend 6–18 inches beyond end supports - Workers must be trained by a competent person before using scaffolding - Never load scaffolds beyond their rated capacity