South Carolina Roofing

5 questions | 8% of exam | Reference: 29 CFR 1926

Key Concepts

Fall Protection (29 CFR 1926.502 & 1926.501)

• Low-slope roofs (≤4:12 pitch): Fall protection required at 6 feet above lower level. Acceptable systems: guardrail, safety net, or personal fall arrest system (PFAS). Warning line + safety monitor is also permitted.
• Steep roofs (>4:12 pitch): Guardrail, safety net, or PFAS required at 6 feet. Warning lines alone are not sufficient.
• The 6-foot trigger height applies to all roofing work.

Personal Fall Arrest System (PFAS) Components

• Anchorage: Must support at least 5,000 lbs. per employee or be designed with 2:1 safety factor by a qualified person.
• Body harness: Full-body harness required (body belts are not acceptable for fall arrest).
• Connector/lanyard: Must limit maximum arresting force to 1,800 lbs.
• Free fall must be limited to 6 feet; worker must not contact lower level.
• Inspection: Inspect before each use. Remove from service immediately if subjected to fall impact. Do not reuse without manufacturer clearance. -…

(8 Questions, 12% of Exam)

Key Concepts

Solid Roof Sheathing is required under asphalt, fiberglass, and metal shingles, mineral-surfaced roll roofing, built-up roofing, tile, slate, and any covering needing continuous support. Spaced (open) sheathing is only appropriate for wood shakes/shingles under specific conditions.

Plywood Grade Minimum: APA recommends (and most codes require) a minimum of C-D Interior with Exterior Glue, or equivalent exterior grade. Index number must be no less than 32/16 (unsanded) or Group 1 (sanded).

OSB/Waferboard: Treated the same as plywood for code purposes; must meet equivalent span ratings and thickness requirements.

Board Sheathing Sizes: Acceptable widths are 1×4, 1×6, 1×8, 1×10, or 1×12. Maximum recommended width is 1×6 — wider boards swell and shrink excessively. Use kiln-dried lumber only; never green or unseasoned lumber.

Board Installation Rules: - Allow minimum ⅛ inch at end joints for expansion - Stagger end joints; center over rafters - Tongue-and-groove boards installed tongue toward the ridge - Avoid loose knots or pitch-saturated boards (pitch dissolves asphalt)

Key Concepts

Asphalt Shingles

• Organic shingles: asphalt-saturated felt base mat, coated both sides, mineral granules on face for weather/fire resistance. Lifespan: 15–20 years.
• Fiberglass (laminated) shingles: 20–30 year lifespan; heavier weight = longer durability.
• Fire ratings: UL Class A (best), B, C — asphalt shingles typically achieve Class A or B.
• Wind ratings: ASTM D3161 (Class C = 60 mph, Class D = 90 mph, Class F = 110 mph); UL 2390 for enhanced wind resistance.
• Adhesive strips (heat-activated) bond tabs to prevent wind uplift.

Underlayment

• No. 15 felt: standard single-layer application on slopes ≥ 4:12.
• No. 30 felt: required on slopes 2:12–4:12 (low-slope applications) and for slate, tile, and wood roofing.
• Ice and water shield (self-adhering): required at eaves in cold climates; extends minimum 24" inside the interior wall line.
• Synthetic underlayment: increasingly common; lighter, higher tear resistance — follow manufacturer specs for coverage.
• Underlayment functions: protects deck before finish roofing, secondary weather barrier, separates wood resins from shingles, cushions brittle…

Key Concepts

System Classifications & Minimum Slopes

• Architectural (structural) metal panel systems require solid substrate support; structural panels (e.g., corrugated steel) can span open framing (purlins).
• Minimum slope for most metal panel systems: ¼:12 — some modern decorative systems can be installed as low as ¼ in 12.
• End lap sealing with caulk is required on slopes less than 4:12.
• End laps must be ≥6 inches on slopes 4:12 and steeper; ≥8 inches on slopes 3:12 to 4:12.

Metal Types & Corrosion Resistance

• Galvanized steel: zinc-coated via hot-dip process; must be cleaned with muriatic acid before painting if new; water-clean only after 1 year of weathering.
• Galvalume: zinc-aluminum alloy coating; superior corrosion resistance over standard galvanized.
• Aluminum: lightweight, naturally corrosion-resistant, no coating required.
• Copper: extremely long-lasting; requires solid sheathing; subject to galvanic corrosion when in contact with dissimilar metals.
• Stainless steel: highest corrosion resistance; terne-coated stainless steel can be installed over fluted metal deck.
• Terne metal, lead, monel, zinc: require solid sheathing…

Key Concepts

Metal Types and Properties

• Aluminum: Lightweight, corrosion-resistant, common for residential flashing; reacts with concrete/mortar and dissimilar metals
• Copper: Premium choice, long-lasting, develops patina; minimum 16 oz/sq ft standard; reactive with aluminum and galvanized steel
• Galvanized steel: Carbon steel with zinc coating; economical but coating degrades over time; do not use with copper
• Galvalume: Steel coated with aluminum-zinc alloy; superior corrosion resistance vs. standard galvanized; better for coastal environments
• Stainless steel: Highest corrosion resistance; expensive; Type 304 or 316 used in roofing
• Lead: Extremely malleable, ideal for complex shapes; toxic concerns limit use; minimum 2.5 lb/sq ft typical
• Lead-coated copper: Combines copper's longevity with lead's stain-prevention (stops copper runoff staining)
• Zinc: Self-healing oxide layer; compatible with most metals; expands significantly with temperature

Key Concepts

Leak Detection & Diagnosis

• Water entry point is rarely directly above where ceiling damage appears — water travels along rafters and sheathing before dripping.
• Attic inspection method: Darken the attic and look for rays of sunlight (nail holes); have a helper hose the roof while you observe from inside. Mark nail holes by pushing a wire through so it's visible from the roof surface.
• Water travel rule: In valleys especially, the actual leak source can be far from where water appears — don't waste time searching attic alone for valley leaks.
• Counterflashing leaks occur when it doesn't lap far enough over base flashing, or from loose mortar. Fix: scrape joints clean to ½ inch depth, fill with butyl rubber caulk or fresh mortar.

Key Concepts

EPDM Membrane

• EPDM (Ethylene Propylene Diene Monomer) is the most widely used single-ply membrane; available in 0.045" and 0.060" thicknesses
• Three installation methods:
• Loosely laid and ballasted – membrane laid over substrate, held down by stone ballast or pavers; fastest to install; can be installed in nearly any weather including wet/icy conditions
• Fully adhered – bonded to substrate using bonding cement across entire surface
• Mechanically fastened – metal stress plates and fasteners at 12" o.c. secure membrane to deck; lap edges sealed with caulk
• Joints between sheets are cemented, taped, hot-air welded, or solvent welded; lap edges must always be caulked

Thermoplastic Single-Ply Membranes

• PVC (Polyvinyl Chloride) – seamed by heat welding or solvent; incompatible with bitumen and coal-tar pitch – requires a slip sheet (separation sheet) between membrane and petroleum-based substrate; lumber in contact with PVC must be wolmanized (pressure-treated)
• CPE (Chlorinated Polyethylene) – heat or solvent welded
• CSPE (Chlorosulfonated Polyethylene / Hypalon) – commonly used as a topcoat over…

Key Concepts

Bitumen Types & Properties

• Asphalt Types I–IV: Higher type numbers = higher softening point and viscosity. Type I (softest) for smooth-surface; Type III–IV (steep asphalt) for hot mopping on slopes.
• Coal-tar pitch: Maximum slope ½ in 12; asphalt bitumen max slope 6 in 12 for smooth/mineral surface, 3 in 12 for aggregate surfacing.
• EVT (Equiviscous Temperature): The ideal application temperature where bitumen flows and bonds correctly. Applying too far from EVT causes improper adhesion or fire risk.
• Flash point: The temperature at which bitumen vapors ignite. Critical safety threshold — never heat beyond flash point.

Ply Sheets & Base Sheets

• Fiberglass felts: Dimensionally stable, resistant to moisture absorption. Organic felts: More flexible but absorb more moisture.
• Venting base sheets: Required over lightweight insulating concrete and gypsum concrete decks to allow moisture vapor to escape — do not hot-mop directly to these substrates.
• Key ASTM standards: ASTM D226 (asphalt-saturated organic felt), ASTM D2178 (fiberglass felt).
• Lap requirements: Each ply is lapped so the…