Arkansas Roofing/Roof Decks - Commercial Exam

Arkansas Roofing/Roof Decks – Commercial Exam | 5 questions (17%)

Key Concepts

• Two ways to figure an irregular level roof. In the positive method, you divide the roof into rectangular areas and add the parts to get the total area. In the negative method, you extend the roof lines to form a single rectangle, calculate that rectangle's area, and subtract the areas of the rectangular spaces that lie outside the actual roof. Both give the same answer, so use whichever requires the fewest calculations. (Roofing Construction and Estimating, Chapter 1, Pages 7–8, Examples 1-1 and 1-2; also Page 1-2)
• Plan dimensions are actual dimensions on a level roof. Area of a level rectangular roof = L × W. (Equation 1-1)
• Slope is expressed as rise in inches per 12 inches of run. A "6 in 12 roof" rises 6 inches for every 12 inches of horizontal run. (Page 1-4; Figure 1-9)
• Net vs. gross area. The net area is the area of roof sheathing that will be covered with roofing material. The gross area is the larger area you must supply material for, allowing for additional felt at the ridge, hips and valleys; a starter course; hip and ridge units; and cutting allowances at rakes, hips and valleys. A roofing square is 100 square feet. (Pages 17–18)
• The universal net-area formula applies only when (1) all roof planes have the same slope and (2) all hips and valleys are framed at 45 degrees with respect to the eaves. When slope changes from one section to another, do a separate take-off for each slope. (Pages 18–19, Example 1-13)
• **Conversion-factor table (Figure 1-19 / Appendix…

Arkansas Roofing/Roof Decks – Commercial (4 questions, 13%)

Key Concepts

Deck and sheathing selection - OSB used for roof sheathing must be a minimum 7/16 inch (nominal) panel. (Roofing Construction and Estimating, Chapter 2—Roof Sheathing, Decking and Loading) - For wood shake and wood shingle roof systems, NRCA recommends a minimum of four-ply, nominal ¾-inch-thick (actual 23/32-inch) plywood for 24-inch rafter spacings; ⅝-inch nominal is the minimum recommended for 16-inch rafter spacings. (NRCA Steep-slope Roof Systems, Wood Shake and Wood Shingle Roof Systems, Section 2.1—Wood Panels) - On a performance-rated panel stamp such as 32/16, the number in front of the slash is the maximum spacing (in inches) of supports when the panel is used for roof sheathing; the number after the slash is the maximum spacing for subflooring. A zero means the panel is unsuitable for that use. (Carpentry and Building Construction, Section 19.5, Pages 562–563)

Panel layout and fastening - Lay panels with the long dimension perpendicular to rafters; end joints occur over rafters and are staggered between adjacent rows. Allow ⅛ inch between panels (at edge and end joints) unless the manufacturer directs otherwise, to prevent buckling. (Section 19.5, Page 563) - Use 6d common, ring-shank or spiral-thread nails for plywood ½ inch thick or less; 8d common nails for thicker plywood. Place nails approximately ⅜ inch in from panel ends and edges. (Section 19.5, Page 564) - Roof sheathing requires ¾-inch clearance from finished masonry on all sides of a chimney opening; framing members require 2-inch clearance for fire protection. (Section 19.5, Page 567)

Key Concepts

Slope and shingle selection - Strip shingles are installed on roofs with a slope of 4-in-12 or greater; 4-in-12 or greater is the "high slope" category. For lower slopes, consult the shingle manufacturer's literature. (Carpentry and Building Construction, Sec. 22.1 — Roof Slope; Sec. 22.2 — Installation Issues) - The 4-inch pattern is used on low-slope roofs of 2 through 3 in 12; the first shingle of each course is trimmed in a multiple of 4 inches, restarting full width at the 10th course. Never use a pattern less than 4 inches. (Asphalt Shingles, Ch. 4)

Underlayment and flashing - Single-coverage underlayment: No. 15 felt rolled from the eave upward, top lap at least 2" at horizontal joints and 4" side lap at end joints. (Carpentry, Sec. 22.2 — Installing Underlayment) - Metal open-valley flashing: each section laps at least 4 inches over the next lowest section; sides extend at least 8 inches up each side of the intersecting roof. (Carpentry, Sec. 22.2 — Open Valleys, Metal) - Eaves protection extends from the end of the eaves to a point at least 22 inches inside the exterior wall line. (Carpentry, Sec. 22.1) Note: IRC R905.1.2 and the NRCA Roofing Manual set the ice barrier at 24 inches inside the exterior wall line — use 24 inches on a code question. - Valley metal for wood shakes/shingles and for clay and concrete tile: minimum 24 inches wide (flanges about 11 inches each side of centerline). (NRCA Steep-slope, Ch. 4, Sec. 4.2 — Valleys)

Arkansas Roofing/Roof Decks – Commercial Exam | 4 questions (13%)

Key Concepts

Wood nailers and blocking - Wood nailers should be a minimum of 2- by 6-inch nominal-dimension lumber. Nailers protect the edges of rigid board insulation and provide a substrate for anchoring flashing materials; they should be securely attached to a roof deck, wall and/or structural framing (NRCA Roofing Manual: Membrane Roof Systems—2023, Chapter 10, pp. 307–308). - Wood nailers must be adequately fastened to the substrate below to resist uplift loads, especially at parapet walls/copings and roof edges where edge-metal shapes are fastened to wood blocking (Ch. 10, p. 307).

Metal flashing components - The bottom of the exterior vertical face of a coping cap or metal edge flashing should be a minimum of 1 inch below the uppermost edge of the exterior wall material (Ch. 10, pp. 309–310). - NRCA does not recommend caulking the joint between the bottom of the exterior vertical face of a coping cap or metal edge flashing and the building exterior — it does not add waterproofing integrity and may hinder the wall's ability to dissipate moisture (Ch. 10, p. 309). - NRCA suggests avoiding, where possible, flashing details requiring rigid metal flanges to be embedded or sandwiched into roof membranes, because differential movement may cause splits, tears or cracks (Ch. 10, p. 309).

Key Concepts

Employee Emergency Action Plans — §1926.35 - The emergency action plan shall be in writing (except as provided in the last sentence of paragraph (e)(3)) and shall cover designated actions employers and employees must take to ensure employee safety from fire and other emergencies — §1926.35(a). - For those employers with 10 or fewer employees, the plan may be communicated orally to employees and the employer need not maintain a written plan — §1926.35(e)(3). Otherwise, the written plan shall be kept at the workplace and made available for employee review. - Minimum plan elements — §1926.35(b): (1) emergency escape procedures and escape route assignments; (2) procedures for employees who remain to operate critical plant operations before evacuating; (3) procedures to account for all employees after evacuation; (4) rescue and medical duties; (5) the preferred means of reporting fires and other emergencies; (6) names or regular job titles of persons or departments who can be contacted for further information. - The employer shall establish an employee alarm system complying with §1926.159 — §1926.35(c)(1).

Safety Training and Education — §1926.21 - Employees required to handle or use poisons, caustics, and other harmful substances shall be instructed regarding the safe handling and use, and be made aware of the potential hazards, personal hygiene, and personal protective measures required — §1926.21(b)(3). - Employees required to handle or use flammable liquids, gases, or toxic materials shall be instructed in the safe handling and use of these materials and made aware of the specific requirements contained in subparts D, F, and other applicable subparts — §1926.21(b)(5). - The employer shall instruct each employee in the recognition and avoidance of unsafe conditions and the…