Alabama Roofing and Sheet Metal Contractor

Alabama Roofing & Sheet Metal Contractor Exam Study Brief

Key Concepts

Roof Area Measurement — Positive vs. Negative Method - Positive method: Measure each roof plane separately and sum them. Used when planes are simple and distinct. - Negative method: Calculate the total footprint (plan view) area, then subtract non-roof areas (skylights, chimneys, HVAC curbs). Faster for complex roofs. - Always work from plan dimensions (horizontal projection), then apply slope factors to get actual surface area.

Slope Definitions - Rise/Run: Expressed as X/12 (e.g., 4/12 = 4 inches of rise per 12 inches of run). - Pitch: Pitch = Rise ÷ Span (span = 2 × run). A 4/12 slope = 4/24 = 1/6 pitch. Note: pitch and slope are NOT interchangeable. - Degrees: Use: Degrees = arctan(rise/run). A 6/12 slope = arctan(0.5) ≈ 26.57°.

Roof Slope Factor (Area Conversion Factor) - Multiply horizontal (plan) area by the slope factor to get actual sloped surface area. - Common slope factors (memorize these):

Rafter Length from Plan Dimensions - Rafter length = Run × Slope Factor. Example: 12-ft run on a 6/12 slope = 12 × 1.118 = 13.42 ft.

Hip and Valley Lengths - Hip/valley runs diagonally across a 45° plan corner. Use the hip/valley length factor (not the standard slope factor). - Hip/valley factor = √(slope² + 144 + 144) ÷ 12, OR look up in appendix tables. - Common hip/valley factors:

Key Concepts

Roof Deck Inspection & Pre-Installation Requirements The roof deck must be structurally sound, dry, and free of defects before any roofing system is installed. Inspect for damaged, delaminated, or deteriorated panels. Fastener patterns must meet manufacturer specs and code requirements. Deck boards must be properly secured with no movement.

Wood Panel Decking (Plywood & OSB) - Plywood and OSB must be rated for roof sheathing use (APA-rated Exposure 1 or Exterior) - Minimum thickness is typically 7/16 inch for OSB and 3/8 inch for plywood for standard rafter spacing, but 15/32 inch (½ inch) is common for 24-inch rafter spacing - Panels must be installed with the long axis perpendicular to supports with staggered (offset) end joints - OSB and plywood carry different performance characteristics in moisture exposure — OSB is more susceptible to edge swell

Structural Load-Bearing Capacity & Deflection - Roof decks must support dead loads, live loads, snow loads, and wind uplift per IBC Chapter 16 - Deflection limit for roof members is typically L/240 under live load only, or L/180 for total load - Ponding must be evaluated; decks must not allow water accumulation beyond design limits per IBC Section 1611

Roof Slope & Drainage Requirements - Minimum slope for positive drainage: ¼:12 (1/4 inch per foot) for low-slope membrane systems - Steep-slope systems (asphalt shingles): minimum 2:12 slope with special underlayment below 4:12 - Metal roofing: minimum slope varies by system (standing seam can go as low as ¼:12; exposed fastener panels typically 3:12 minimum) - Secondary overflow drains or scuppers are required per IBC Section 1502.2 where perimeter construction can trap water; scuppers must have a minimum 4-inch opening (IBC §1502.3)…

Alabama Roofing and Sheet Metal Contractor Exam — 27 Questions (45% of Exam)

Key Concepts

Asphalt Shingles

• Minimum slope for standard asphalt shingles: 4:12. Slopes 2:12–4:12 require double underlayment and low-slope application method.
• Shingles below 2:12 are not permitted without special waterproofing systems.
• Standard exposure for 3-tab shingles: 5 inches. Nailing: minimum 4 nails per shingle, placed above the cutouts.
• Ice and water shield (self-adhering underlayment) required at eaves from the edge to 24 inches inside the exterior wall line in cold climates.

Underlayment (Steep-Slope)

• #15 felt: single-layer for slopes ≥ 4:12; double-layer for slopes 2:12–4:12 with 19-inch top lap.
• #30 felt: heavier, used for tile and slate; typically single layer.
• Synthetic underlayments are increasingly common and often rated as equivalents to felt.
• Drip edge installs under underlayment at eaves, over underlayment at rakes.
• Valley flashing: open valleys use metal (minimum 24-gauge galvanized or equivalent); closed-cut and woven valleys use mineral-surface roll roofing or self-adhering membrane.

Built-Up Roofing (BUR)

• BUR systems consist of alternating layers of bitumen (asphalt or coal tar pitch) and reinforcing felts (ply sheets), topped with a surfacing (gravel, slag, cap sheet, or aluminum coating).
• Asphalt types (ASTM D312): Type I (dead-level), Type II (flat), Type III (steep), Type IV (special steep) — matched to roof slope.
• Coal tar pitch: used only on slopes ≤ ½:12; more resistant to ponding water than asphalt.
• Minimum 3-ply system for most commercial applications; 4-ply for high-performance.
• Gravel surfacing: minimum 400 lbs per square; slag: minimum 300 lbs per square.

15% of exam | ~9 questions

Key Concepts

Roof Deck & Sheathing (IBC Chapter 15 / IRC R803)

• Solid decking: Boards or plywood with no gaps; required for shingles, tile, and most steep-slope applications
• Spaced (open) decking: Boards with gaps; acceptable for certain wood shakes and clay/concrete tile where ventilation beneath the covering is needed
• Plywood/OSB: Must be minimum 3/8" for most applications; thickness and span rating must match rafter/truss spacing
• Board sheathing: 1× nominal lumber; must be properly dried and graded

Underlayment Classifications

Underlayment Application by Slope

• Steep-slope (≥4:12): Single layer of No. 15 felt, or per manufacturer's instructions
• Low-slope (2:12–4:12): Double layer of No. 15 felt or single layer No. 30; lapped per code
• Below 2:12: Not acceptable for asphalt shingles; requires low-slope membrane system
• Metal roofing: Underlayment requirements vary; self-adhering membrane often specified at seams and eaves

29 CFR 1926 | 6 questions, 10% of exam

Key Concepts

Fall Protection (§1926.500–.502)

• Low-slope roofs (≤4:12 pitch): Use guardrail systems, safety net systems, or personal fall arrest systems (PFAS). Warning line systems alone are acceptable only when combined with a safety monitor or when workers stay inside the warning line.
• Steep roofs (>4:12 pitch): Guardrail systems with toeboards, safety net systems, or PFAS required — no warning-line-only option.
• Fall protection required at 6 feet above a lower level in construction.

Personal Fall Arrest Systems (§1926.502(d))

• Components: Body harness (full-body only — belts prohibited for fall arrest), lanyard, deceleration device, anchorage.
• Criteria: Must limit arresting force to 1,800 lbs; limit free fall to 6 feet; bring worker to a stop within 3.5 feet after activation; anchorage must support 5,000 lbs per worker (or be designed by a qualified person with 2:1 safety factor).
• Inspection: Inspect before each use; remove from service if subjected to impact loading.

Guardrail Systems (§1926.502(b))

• Top rail height: 42 inches (±3 inches) above walking/working surface.
• Mid-rail: at 21 inches (midpoint between top rail and surface).
• Top rail must withstand 200 lbs of outward/downward force at any point.
• Mid-rail must withstand 150 lbs.
• Wire rope top rails must be flagged every 6 feet with high-visibility material.