Exam Cheat Sheet · Quick Reference

Arkansas Roofing/Roof Decks - Commercial Exam

Arkansas  ·  PSI Services Contractor

Verified, not estimated. Every figure below is drawn from the official exam structure we maintain — question counts, passing standard and topic weighting. Practice questions are grounded in the source law with statute citations. We omit any figure we can't verify rather than guess at it.
Total questions
30
Passing score
70%
Exam time
75 min
Administered by
PSI Services Contractor
Format
Reference materials allowed

Arkansas State Portion 30 questions

Estimating and Plan Reading 5 Q · 17%
Surface Preparation and Planning 4 Q · 13%
Steep Slope Roofing, including BUR, Waterproofing 14 Q · 47%
Roofing Components 4 Q · 13%
OSHA Safety 3 Q · 10%

Key Distinctions

Positive method of roof measurementvsNegative method of roof measurement

The positive method divides an irregular roof into rectangles and adds their areas, while the negative method extends roof lines to form one large rectangle and subtracts the areas that are not roof; both yield identical results.

Roofing Construction and Estimating, Chapter 1, Pages 7-8
Nailable deckvsNonnailable deck

Nailable decks (wood panels, wood planks, cementitious wood fiber panels, lightweight insulating concrete) accept mechanical fasteners, while a nonnailable deck (example: structural concrete) is a substrate where mechanical fasteners are not used to attach roof system components — steel deck is a separate category used only for temporary roof configurations.

NRCA Roofing Manual: Membrane Roof Systems (2023), Chapter 1—Roof Assembly Configurations, Substrate Type definitions
Fiberglass asphalt shinglesvsOrganic asphalt shingles

Fiberglass shingles use a fiberglass base mat saturated and covered with flexible asphalt and surfaced with mineral granules, while organic shingles use a cellulose-fiber base mat.

Roofing Construction and Estimating, Chapter 4—Asphalt Shingles
ASTM D312 Type III asphaltvsASTM D312 Type IV asphalt

Type III is generally appropriate for interply moppings in built-up membrane application where the completed membrane slope is 1:12 or less; Type IV is suggested for slopes greater than 1:12.

NRCA Roofing Manual: Membrane Roof Systems (2023), Chapter 5, Page 192
ASTM D4637 EPDM Type I and Type IIvsASTM D4637 EPDM Type III

Type I designates nonreinforced EPDM sheets and Type II designates EPDM sheets reinforced internally with scrim or fabric, while Type III designates EPDM sheets with fabric backing.

NRCA Roofing Manual: Membrane Roof Systems (2023), Chapter 5, Pages 216-217
Unit run of a common raftervsUnit run of a hip rafter (45° to ridge)

A common rafter (90° to the ridge) always has a unit run of 12 inches, while a rafter at 45° to the ridge, such as a hip rafter, uses a unit run of 17 inches.

Carpentry and Building Construction, Section 17.1, Page 470
Temporary truss bracingvsPermanent truss bracing

Temporary bracing (such as ground bracing of the gable-end truss with lumber standoffs anchored to stakes) serves during initial installation, while permanent bracing on long-span trusses prevents the bottom chords from moving as the ceiling finish is applied.

Carpentry and Building Construction, Section 17.4, Page 496-497
Mark (IBC 2015 Ch. 2)vsLabel / Manufacturer's designation (IBC 2015 Ch. 2)

A mark is an identification applied by the manufacturer showing the manufacturer's name and the product's function; a label additionally carries performance characteristics and the identification of an approved agency, and a manufacturer's designation indicates compliance with a specified standard or set of rules.

IBC 2015 Chapter 2 — Definitions of 'Mark,' 'Label' and 'Manufacturer's Designation'
Wind-uplift safety factor for low-slope membrane roof systemsvsWind-uplift safety factor for steel deck assemblies with steel/aluminum metal panel roof systems

NRCA considers a minimum safety factor of 2.0 appropriate for low-slope membrane roof systems (based on ASTM D6630), while 1.67 applies to steel deck assemblies with steel or aluminum metal panel roof systems.

NRCA Roofing Manual: Membrane Roof Systems (2023), Appendix 1, Page 578
ASCE 7-16 Zones 1/1' and Zone 2vsASCE 7-16 Zone 3

For roofs with slopes no greater than 1½:12, Zones 1 and 1' are the roof field and Zone 2 is the perimeter region, while Zone 3 is the corner region, which experiences the highest design wind load values.

NRCA Roofing Manual: Membrane Roof Systems (2023), Appendix 1, Page 577
Strength design live load factor f1 (IBC 2015 §1605.2)vsStrength design snow load factor f2 (IBC 2015 §1605.2)

f1 is 0.5 for ordinary live loads and 1 for public assembly live loads over 100 psf and parking garages, while f2 is 0.7 for roof configurations (such as saw tooth) that do not shed snow and 0.2 for other roof configurations.

IBC 2015 Chapter 16 — Section 1605.2 Load Combinations Using Strength Design or Load and Resistance Factor Design
Battens optional on tile roofsvsBattens required on tile roofs

Battens can be installed on roof slopes of 2-1/2 in 12 and steeper, but they are required on slopes of 7 in 12 and steeper.

Roofing Construction and Estimating, Chapter 7 — Tile Roofing
First number on a performance-rated panel stamp (e.g., 32/16)vsSecond number on a performance-rated panel stamp

The number before the slash is the maximum spacing of supports in inches for roof sheathing use; the number after the slash is the maximum spacing for subflooring use.

Carpentry and Building Construction, Section 19.5, Pages 562-563

Key Terms

Competent person (OSHA 29 CFR 1926.32(f)) OSHA 1926 CFR 29, §1926.32(f), Page 31
One who is capable of identifying existing and predictable hazards in the surroundings or working conditions that are unsanitary, hazardous, or dangerous to employees and who has authorization to take prompt corrective measures to eliminate them.
Material Safety Data Sheet (MSDS) Carpentry and Building Construction, Construction Safety & Health, Book Page 92
A manufacturer-supplied document shipped with products that explains product hazards, physical data (such as melting point or flash point), toxicity levels, first-aid recommendations, storage and disposal, protective equipment, and spill/leak response; every worker must have access to MSDS on the job site.
Emergency action plan for small employers (OSHA 29 CFR 1926.35(e)(3)) OSHA 1926 CFR 29, §1926.35(e)(3)
For employers with 10 or fewer employees, the plan may be communicated orally to employees and the employer need not maintain a written plan.
Personal protective equipment responsibility (OSHA 29 CFR 1926.28(a)) OSHA 1926 CFR 29, §1926.28, Page 31
The employer is responsible for requiring the wearing of appropriate personal protective equipment in all operations where there is exposure to hazardous conditions or where the part indicates the need for such equipment to reduce hazards.
Waste container covers (OSHA 29 CFR 1926.25(c)) OSHA 1926 CFR 29, §1926.25(c)
Containers used for garbage and other oily, flammable, or hazardous wastes such as caustics, acids, and harmful dusts shall be equipped with covers.
Hazardous-material instruction (OSHA 29 CFR 1926.21(b)(3) and (b)(5)) OSHA 1926 CFR 29, §1926.21(b)(3)
Employees required to handle or use poisons, caustics, other harmful substances, flammable liquids, gases, or toxic materials shall be instructed in safe handling and use and made aware of potential hazards, personal hygiene, and required personal protective measures.
Collar tie Carpentry and Building Construction, Section 17.1, Page 468
A horizontal tie that connects opposite pairs of rafters to help stiffen the roof.
Ridge board Carpentry and Building Construction, Section 19.1, Page 530
Usually nominal 2-inch lumber slightly wider than the rafter stock so angled rafter end cuts bear fully on it (for example, 2×10 ridge with 2×8 rafters).
Closed cornice Carpentry and Building Construction, Section 19.4, Page 552
A cornice on a house with no rafter overhang; seldom used on newer houses because of the difficulty of providing adequate attic ventilation.
Skirtboard Carpentry and Building Construction, Page 723
A finish trim piece running along the wall on the closed side of a stairway that covers the joint where tread and riser ends meet the wall, serving both decorative and protective functions.
Equiviscous temperature (EVT) Roofing Construction and Estimating, Chapter 10 — Built-Up Roofing
The temperature at which a bitumen attains 125 centipoise — the optimum temperature and viscosity for application; roofing bitumen should be applied within 25°F of the EVT.
Allowance factor Roofing Construction & Estimating, Page 1-10 (Chapter 1)
The ratio of gross material quantity (including waste, lapping, and starter courses) to net roof area; e.g., 18 squares ÷ 15 squares = 1.20, a 20 percent allowance.
Eaves protection (ice barrier) Carpentry and Building Construction, Section 22.1 — Eaves Protection / Placement of Eaves Flashing
Protection that should extend from the end of the eaves to a point at least 22 inches inside the exterior wall line per the text; on a code question use 24 inches (IRC R905.1.2 and the NRCA Roofing Manual).
4-inch shingling pattern Roofing Construction and Estimating, Chapter 4 — Asphalt Shingles
A low-slope pattern used on roofs from 2 through 3 in 12 in which the first shingle of each course is trimmed in a multiple of 4 inches, starting again with a full-width shingle at the 10th course; never use a pattern less than 4 inches.
Class B fire extinguisher Carpentry and Building Construction, Construction Safety & Health, Page 81
Rated for fires involving grease, oil, and chemicals (Class A = wood, paper, cloth, plastic; Class C = electrical equipment; Class D = combustible metals); combination ratings such as A:B or A:B:C also apply to Class B fires.
IRC option for townhouses (2015 IBC §101.2 Exception) IBC 2015 Chapter 1 — Section 101.2 Scope
Detached one- and two-family dwellings and multiple single-family dwellings (townhouses) not more than three stories above grade plane with a separate means of egress, and their accessory structures not more than three stories, may comply with the International Residential Code.
Temporary roof membrane exception for polymer-modified bitumen (NRCA 5.3) NRCA Roofing Manual: Membrane Roof Systems (2023), Section 5.3—Polymer-modified Bitumen Roof Membranes
NRCA does not recommend polymer-modified bitumen roof membranes in a single-layer configuration except where used as a temporary roof membrane; most specifications use multiple-layer configurations.

Formulas to Know

Roof area by the negative methodTotal roof area = area of extended rectangle − sum of non-roof (exterior) areas; worked example: (80 × 50) − [(20 × 15) + (10 × 15)] = 4,000 − 450 = 3,550 SF
Roof slope as rise per 12 inches of runSlope = (Total Rise ÷ Total Run) × 12; worked example: (7.5 ft ÷ 15 ft) × 12 = 6, i.e., 6 in 12
Actual common rafter lengthActual rafter length = Run × roof-slope factor (Column 2 of the conversion factor table); worked example: 14 ft × 1.202 (8 in 12) = 16.83 LF
Plan length of a hip rafter (conventional framing)Plan length = 1.414 × run; worked example: 1.414 × 14 ft = 19.80 ft
Valley length where roofs of unequal slope intersectActual valley length = run of the LOW-sloping roof × valley length factor (Appendix B); worked example: 24 ft × 1.247 = 29.93 LF
Material allowance factorAllowance factor = gross area including allowances ÷ net roof area; worked example: 18 squares ÷ 15 squares = 1.20
Labor unit price per square (Equation 14-1)Unit price = (crew hourly rate × 8 hours) ÷ daily crew production in squares; worked example: ($25.00 + $10.00) × 8 = $280.00 ÷ 6.37 squares = $43.96/square
Roof sheathing panel countPanels = roof area ÷ 32 SF per panel, then add 5 percent for trim and waste; worked example: 72.19 × 0.05 = 3.6; 72.19 + 3.6 = 75.79 → 76 sheets
Board feet of roof framing lumber (board-feet table method)Board feet = (roof surface area ÷ 100) × table board-feet per 100 SF; worked example: 2,100 ÷ 100 = 21; 21 × 102 (2×6 rafters at 16" OC) = 2,142 BF, including common rafters, hip and valley rafters, ridge boards, and collar ties
Gutter slope / total dropMetal gutters slope at least 1 inch every 16 feet (1/16 inch per foot) toward the downspouts; worked example: 32 ft × 1/16 = 2 inches total drop (maximum distance from gutter high point to downspout should not ordinarily exceed 25 feet)
Minimum roof drain sump sizeSump dimension not less than drain bowl diameter + 24 inches; worked example: 12-inch bowl → 36 inches by 36 inches
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