Louisiana Residential Construction

Key Concepts

Soil Classification & Bearing Capacity - Bearing capacity is the load per square foot a soil can safely support. Footings must be sized to spread the load within the soil's capacity. - Soil types ranked from weakest to strongest bearing capacity (generally): organic/fill < clay < silt < sand < gravel < bedrock. - Unstable or expansive soils require special footing designs or soil improvement before building.

Site Layout - A plot plan shows the building's location on the lot, including elevations and setbacks. - Site layout is the process of physically marking the building location on the ground to match the plot plan. - Batter boards are set outside the excavation area (typically 4–6 ft beyond corners) so strings can be re-established after digging. They must remain undisturbed during excavation. - Benchmarks are fixed reference points for elevation. A station mark is a surveyed point used to establish grades and locations. - The 3-4-5 rule (or multiples: 6-8-10, 9-12-15) is used to establish square corners: if one leg = 3, other…

Key Concepts

Concrete Mixture Components

• Portland cement types: Type I (general use), Type II (moderate sulfate resistance), Type III (high early strength), Type IV (low heat), Type V (high sulfate resistance)
• Water-cement (w/c) ratio: Lower ratio = stronger, more durable concrete. Typical residential: 0.40–0.50
• Aggregates: Fine (sand) and coarse (gravel/stone). Must be clean, well-graded, and free of organics
• Supplementary cementitious materials (SCMs): Fly ash, slag cement, silica fume — improve workability, durability, and reduce heat of hydration

Admixtures

• Air-entraining: Creates microscopic air bubbles; improves freeze-thaw resistance and workability — reduces strength slightly
• Accelerating (e.g., calcium chloride): Speeds set time; useful in cold weather — can corrode steel reinforcement
• Retarding: Slows set time; useful in hot weather or long hauls
• Water-reducing (plasticizers): Maintain workability at lower w/c ratio; improve strength without adding water

Key Concepts

Clay Brick Types & ASTM Standards

• ASTM C62 covers building brick; ASTM C216 covers facing brick; ASTM C652 covers hollow brick
• Grades are based on weathering resistance: SW (Severe Weathering), MW (Moderate Weathering), NW (Negligible Weathering)
• SW brick is required for below-grade and high-exposure applications in Louisiana's climate

Concrete Masonry Units (CMU)

• ASTM C90 governs load-bearing CMU; ASTM C129 governs non-load-bearing CMU
• Standard CMU nominal size: 8" × 8" × 16" (actual: 7⅝" × 7⅝" × 15⅝")
• CMU grades: Grade N (general use, above/below grade) and Grade S (above grade only, protected from weather)
• Hollow CMU must be grouted and reinforced when used in structural or reinforced wall systems

Mortar Types (ASTM C270)

• Type M: Highest strength (~2,500 psi), best durability; use below grade, retaining walls, foundations
• Type S: High strength (~1,800 psi), good flexibility; use at or below grade, exterior walls
• Type N: Medium strength (~750 psi), most versatile; use above grade, general exterior
• Type O: Low…

Key Concepts

Wood Properties, Lumber Grading & Moisture Content

• Lumber is graded by agencies such as the Southern Pine Inspection Bureau (SPIB). Grades include Select Structural, No. 1, No. 2, and No. 3 — higher grade = fewer defects = greater allowable loads.
• Moisture content (MC) is critical: lumber used in framing should be at or below 19% MC. Lumber above 19% MC is considered "green" and will shrink, warp, or split as it dries.
• Equilibrium moisture content (EMC) is the point at which wood neither gains nor loses moisture relative to its environment.

Engineered Wood Products

• Plywood: Graded by face/back veneer (A–D) and exposure rating (Exposure 1, Exterior). Span rating printed on panels indicates joist spacing.
• OSB (Oriented Strand Board): Directional — install with the strength axis (long dimension) perpendicular to framing members.
• LVL (Laminated Veneer Lumber): Used for headers and beams; high strength, minimal crown. Install with crown up.
• Glulam: Layered dimensional lumber; used for long-span beams and arches.
• I-Joists: Consist of…

Key Concepts

Drywall Types and Applications - Standard drywall (Type W): Used in typical interior walls and ceilings. - Type X: Fire-rated; contains glass fibers for added resistance. Minimum ⅝" thick for 1-hour fire assemblies; ½" for some assemblies. - Type C: Enhanced fire resistance beyond Type X; maintains integrity longer under heat due to additional glass fibers and vermiculite. - Moisture-resistant (MR/green board): For bathrooms and kitchens — NOT a substitute for cement board in wet/shower areas. - Cement board: True tile backer for showers and wet areas.

Drywall Sizes: Standard panels are 4'×8', 4'×10', 4'×12'. Thickness ranges from ¼" to ⅝".

Fasteners and Spacing (IRC Table R702.3.5) - Nails: Ring-shank or cooler nails; minimum 1⅛" penetration into framing. - Screws: Type W (wood) or Type S (steel framing); minimum 1" penetration into wood framing. - Nail spacing: Maximum 7" o.c. on ceilings, 8" o.c. on walls (single nailing); with adhesive, 16" o.c. permitted on walls. - Screw spacing: Maximum 12" o.c. on ceilings, 16" o.c. on walls (with adhesive allowed at 24"…

Key Concepts

Roof Measurement & Area Calculation - Roofing is sold and estimated by the square — one square covers 100 sq. ft. of roof surface. - To calculate squares needed: calculate total roof surface area, divide by 100, then add waste factor (typically 10–15% for cuts and overlaps). - Slope is expressed as rise over run (e.g., 4:12 = 4" rise per 12" of horizontal run). Slope determines allowable roofing materials and underlayment requirements.

Roof Sheathing & Decking - Sheathing must be solid and structurally sound before any roofing is applied. Minimum thickness depends on rafter spacing. - Spaced (skip) sheathing is acceptable under wood shingles and shakes; solid decking is required under asphalt shingles and most other materials.

Underlayment Requirements - Standard underlayment: #15 or #30 felt (asphalt-saturated). - Low-slope asphalt shingles (2:12–4:12): double-layer underlayment required; single layer for slopes 4:12 and above. - Ice and water shield (self-adhering membrane) required at eaves in cold climates and at valleys — protects against ice dams. - Ice dams form when heat escapes through…

Louisiana Residential Construction Licensing Exam — 22% of Exam (18 Questions)

Key Concepts

Building Permits & Inspections

• A building permit is required before beginning any new construction, addition, or significant alteration on a one- or two-family dwelling.
• Typical inspection sequence: footing → foundation → framing → rough MEP (mechanical/electrical/plumbing) → insulation → final.
• Work must not be covered before the required inspection is approved. Inspectors can order work to be uncovered if buried prematurely.
• The IRC (International Residential Code) governs one- and two-family dwellings and townhouses not more than three stories above grade.

IRC Scope & Applicability

• IRC applies to detached one- and two-family dwellings and townhouses up to 3 stories with separate means of egress.
• Commercial, multi-family (3+ units), and mixed-use buildings fall under the IBC, not the IRC.
• IRC integrates building, mechanical, plumbing, and energy provisions into one code document.

Key Concepts

Fall Protection (29 CFR 1926 Subpart M)

• 6-foot rule: Fall protection required for residential construction when workers are exposed to falls of 6 feet or more to a lower level.
• Three accepted systems: guardrail systems, safety net systems, or personal fall arrest systems (PFAS).
• Guardrail top rail height: 42 inches (±3 inches); mid-rail at 21 inches; withstand 200 lbs of force.
• PFAS must limit free fall to 6 feet and arrest force to 1,800 lbs; anchor must support 5,000 lbs per worker.
• Safety nets must be installed within 30 feet below the working surface.

Scaffold Safety (29 CFR 1926 Subpart L)

• Scaffolds must support 4 times the maximum intended load.
• Platform planks must be at least 2 inches thick (nominal); fully planked or decked.
• Guardrails required when scaffold is 10 feet or more above lower level.
• Workers must not work on scaffolds during storms or high winds unless a competent person determines it is safe.
• Scaffolds must be erected, moved,…