Florida Roofing Contractors General Trade Knowledge Exam

Key Concepts

Asphalt Types (ASTM D312)

Four classifications based on softening point and application slope: - Type I — Low slope (dead level); lowest softening point (~135°F); used where ponding may occur - Type II — Moderate slope; general-purpose asphalt - Type III — Steep slope; higher softening point (~185–200°F) - Type IV — Special steep; highest softening point; vertical or near-vertical applications

EVT (Equiviscous Temperature) is the ideal application temperature for each asphalt type. Always apply within ±25°F of EVT. Flash point minimum is 500°F — never exceed this during kettle heating.

Coal Tar Pitch Rules

• Used on dead-level or nearly flat roofs (less than ¼"/ft slope)
• Not recommended for slopes exceeding 1"/ft
• Can only be used with tar-saturated felts — do NOT mix coal tar pitch with asphalt felts
• Prone to ponding issues; sloped or tapered insulation may be required to manage drainage

Key Concepts

Roofing Squares: All roofing is estimated by the square = 100 sq ft. Standard asphalt shingles: 3 bundles per square. Heavier or dimensional shingles may require 4+ bundles.

Wood Shingles vs. Wood Shakes: - Shingles: Sawn smooth on both sides; lighter, lower profile - Shakes: Split (hand-split, hand-split & resawn, or taper-sawn); thicker, rougher texture - Wood shakes require an interlayment (18" felt strip between each course); shingles generally do not - Double the starter course at all eaves for both shingles and shakes

Exposure & Coverage: - Exposure depends on slope and product type. Lower slopes = reduced exposure - Wood shingles: 3-ply coverage minimum required; standard exposures are 5" (16" shingle), 5¾" (18"), 7½" (24") - Shakes: standard exposure 7½" to 10" depending on length and slope - Minimum slope for wood shingles: 3:12; shakes: 4:12 (with interlayment)

Key Concepts

Metal Types and Compatibility - Common metals: galvanized steel, copper, aluminum, stainless steel, lead-coated copper, terne (80% lead, 20% tin over copper-bearing carbon steel), terne-coated stainless - Terne and aluminum = least expensive; copper and lead = most costly - Dissimilar metals must be isolated to prevent galvanic corrosion. Use isolation tape, non-conductive coatings, or separating membranes where metals contact each other - Runoff from copper will corrode aluminum and galvanized steel downstream — avoid copper upslope of incompatible metals - Galvanic scale: the further apart two metals are on the galvanic series, the greater the corrosion risk

Panel Systems and Minimum Slopes - Flat seam: minimum slope ¼" per foot - Standing seam and batten seam: minimum slope 2½" per foot - Architectural panels = aesthetic-driven, concealed fasteners; structural panels = load-bearing, exposed or concealed fasteners - "Bermuda" roof: metal applied over wood steps, minimum 2½" per foot slope; interlocked at…

Key Concepts

Membrane Types & ASTM Standards

• EPDM (Ethylene Propylene Diene Monomer) — ASTM D4637; rubber-based, black or white, highly elastic (up to 450%), compatible with most substrates
• TPO (Thermoplastic Polyolefin) — ASTM D6878; heat-weldable seams; tested under TAS 131 for Florida/HVHZ approval
• PVC (Polyvinyl Chloride) — ASTM D4434; heat-weldable, chemical resistant; incompatible with bitumen/coal-tar pitch — requires a slip sheet when applied over asphalt-based substrates
• CSPE (Chlorosulfonated Polyethylene, "Hypalon") — ASTM D3468; adhered with contact cement; seams made with adhesive, not heat
• KEE (Ketone Ethylene Ester) — high plasticizer retention; used in chemically demanding environments

Installation Methods

• Adhered systems: Adhesive applied to both substrate and membrane; solvent-based adhesives must off-gas before bonding (wait for "tacky" stage, not wet); sun and heat accelerate flash-off — adjust open time in hot Florida conditions
• Mechanically fastened systems: Fasteners and plates anchor membrane or insulation through the deck;…

Key Concepts

Asphalt Types & Properties

• Type I (Dead Level): Lowest softening point; use on slopes 0–½ in/ft
• Type II (Flat): Use on slopes up to 1 in/ft
• Type III (Steep): Use on slopes up to 2 in/ft
• Type IV (Special Steep): Highest softening point; use on slopes up to 3 in/ft
• Asphalt must be applied within its EVT (Equiviscous Temperature) range — too cold = poor adhesion; too hot = runs and drips

Modified Bitumen Membrane Types

• APP (Atactic Polypropylene): Plastic modifier; heat-welded or cold-applied; higher softening point; more UV resistant; torch-applied
• SBS (Styrene-Butadiene-Styrene): Rubber modifier; cold-applied, hot-mopped, or heat-welded; more flexible in cold temps; elongation up to 200%
• SA (Self-Adhering): Peel-and-stick; no open flame; requires clean, primed substrate; performance depends heavily on surface temp (min 40°F typically)

Key Concepts

Material Standards - Clay tile governed by ASTM C1167; concrete tile by ASTM C1492 - Water absorption, breaking strength, and freeze-thaw resistance are the three core material properties tested under both standards - Minimum breaking strength and freeze-thaw compliance are mandatory for Florida product approval

Tile Profiles - Flat/low profile: interlocking or plain; low water management demand - S-tile (two-piece): combination of pan (under) and cover (barrel) tiles; also called "mission" style - Barrel/pan and cover: two-piece system; pan lays concave-up, cover lays concave-down over the joint - Interlocking: single-piece with mechanical side lap — most wind-resistant profile

Roof Deck Requirements - Minimum 15/32" plywood or equivalent for tile systems - Deck must provide adequate fastener withdrawal resistance — tile is significantly heavier than other roofing; structural load analysis is required - Dead load of concrete/clay tile ranges from 9–12 psf — always verify structural adequacy before installation

Key Concepts

Dampproofing vs. Waterproofing

• Dampproofing resists moisture migration only — no significant hydrostatic pressure. Applied as solvent-based or bituminous-emulsion coatings. Used on walls above grade or where water table is not a concern.
• Waterproofing resists liquid water under hydrostatic pressure. Required below grade when soil is saturated or water table can rise against the structure.
• When there is any positive hydrostatic head, dampproofing is never sufficient — full membrane waterproofing is required.

When Membrane Waterproofing Is Required

• Below-grade walls and floor slabs subject to hydrostatic pressure
• Planters, plaza decks, tunnels, and subterranean structures
• Any condition where water can accumulate against the structure under pressure

Key Concepts

Water Flow & Scupper Overflow Requirements Scuppers serve as primary or secondary (overflow) drainage. Overflow scuppers must be sized to handle the full design rainfall intensity if primary drains become blocked. The inlet elevation of secondary/overflow drains and scuppers must be set 2 inches above the low point of the roof (above the primary drain inlet) to ensure primary drains function first before overflow is triggered. Scupper openings must be at least as large as the required drainage area dictates based on rainfall intensity and tributary roof area.

Secondary Overflow Drain Placement Secondary (overflow) drain inlets must be positioned so that if primary drains fail, water does not accumulate beyond the structural load capacity of the roof. The inlet elevation of overflow drains must be a minimum of 2 inches above the primary drain inlet. Scupper overflow openings in parapet walls must be located at this same 2-inch-above-low-point elevation.

Key Concepts

General Safety & Health (29 CFR 1926 Subpart C)

• §1926.20: Employers must initiate and maintain accident prevention programs. Competent persons must conduct frequent and regular inspections of job sites, materials, and equipment.
• Unsafe equipment must be tagged, locked out (controls rendered inoperable), or physically removed — not just set aside.
• Only employees qualified by training or experience may operate equipment and machinery.
• Prime contractor retains overall responsibility even when work is subcontracted. Prime and subcontractor have joint responsibility for OSHA compliance on subcontracted work.
• §1926.21: Employer must instruct each employee in recognition and avoidance of unsafe conditions. Employees handling flammable liquids, gases, or toxic materials must receive specific instruction on safe handling.
• Each failure to provide PPE or training to an individual employee is a separate OSHA violation.