Exam Cheat Sheet · Quick Reference
Louisiana Roofing, Sheet Metal and Siding
Louisiana · 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
50
Passing score
70%
Exam time
120 min
Administered by
PSI Services Contractor
Format
Reference materials allowed
Louisiana State Portion 50 questions
Estimating and Plan Reading
5 Q · 10%
Measuring and calculating roof area (level and sloped roofs)Roof slope and pitch calculations using slope factorsQuantity takeoff for specific roofing materials (shingles, tile, slate, metal panels, roll roofing)Estimating underlayment quantities including lap and overcut allowancesLabor unit pricing and production rate calculationsAdjusting published labor costs to actual crew wagesEstimating gutter, downspout, and accessory quantitiesWaste factors for roofing materials
Surface Preparation and Planning
5 Q · 10%
Roof deck inspection procedures and acceptance criteriaRoof deck types and material requirements by roofing systemPlywood and OSB sheathing specifications, thickness, and grading standardsDeck surface condition requirements before roof system applicationRoof slope and drainage design requirementsUnderlayment selection and installation based on roof slope and material typeEvaluation of existing roof systems for re-cover versus replacementStructural load considerations for roof decks including dead and live loads
Steep and Low Slope Roofing including BUR and Waterproofing
18 Q · 36%
Asphalt shingle types, materials, and installation requirementsSteep slope roof underlayment types, configurations, and applicationBuilt-up roofing (BUR) components, bitumens, and installation methodsLow-slope membrane roof systems including polymer-modified bitumen, EPDM, and thermoplastic membranesClay, concrete, and slate tile roof systems including profiles, materials, and installationWood shake and wood shingle roof systems including grades, materials, and installationRigid board insulation types, R-values, and thermal performance for low-slope roofsFlashing, drainage, fire classification, and wind uplift requirements per IBC/IRC
Roofing Components
10 Q · 20%
Asphalt shingle types, materials, and UL fire/wind ratingsRoof deck types and sheathing requirements for steep-slope systemsUnderlayment types, configurations, and slope requirementsValley flashing and drip edge componentsWood shingles and shakes: grades, types, and installation requirementsClay, concrete, and slate tile types, profiles, and physical propertiesMetal roofing and siding materials, seam types, and panel systemsBuilt-up and elastomeric roofing membrane components and substrate requirements
Safety
5 Q · 10%
Fall protection requirements for roofing work (low-slope and steep roofs)Personal fall arrest systems: components, specifications, and proper useGuardrail systems: height, strength, and construction requirementsScaffold safety: capacity, platform construction, and fall protectionLadder and stairway safety requirementsFire protection and prevention on construction sitesPersonal protective equipment selection, use, and employer responsibilitiesAsbestos hazards in roofing and construction: identification, exposure limits, and work practices
Repairs and Reroofing
7 Q · 14%
Reroofing terminology: re-covering vs. tear-off and replacement definitionsEvaluation of existing roof systems prior to reroofing (interior inspection, deck underside, perimeter, rooftop inspection)Roof deck condition assessment and moisture detection methods (core cuts, infrared thermography, nondestructive testing)Re-covering eligibility criteria by roof system type (asphalt shingle, metal shingle, slate, clay/concrete tile, wood shake/shingle, membrane)Flashing inspection and treatment during reroofing (base flashings, counterflashings, drip edge, penetration flashings)Building code requirements for reroofing under IBC and IRC (Section 1512 re-cover and replacement provisions, layer limits, fire classification)Repair techniques by roof covering type (asphalt shingle patching, wood shingle/shake replacement, slate nail-and-bib method, membrane repairs, tile repair)Identifying and locating roof leaks (attic inspection, water staining patterns, chimney/valley/vent flashing failures, miscellaneous leak sources)
Key Distinctions
Positive method (roof measurement)vsNegative method (roof measurement)
The positive method divides an irregular roof into rectangles and adds their areas, while the negative method extends the 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 7-8Fiberglass asphalt shinglesvsOrganic asphalt shingles
Fiberglass shingles use a fiberglass base mat saturated and covered with flexible asphalt and surfaced with mineral granules, whereas organic shingles use a cellulose-fiber base mat.
NRCA Roofing Manual: Architectural Metal Flashing Condensation and Air Leakage Control, and Reroofing, Appendix 6—Climatic Design Information (glossary, "asphalt shingle")Nailing shingles to wood plank/board deckvsNailing shingles to plywood less than ¾ inch thick
Into wood plank or board decks nails must penetrate at least ¾ inch, while into plywood less than ¾ inch thick nails must extend a minimum of ⅛ inch through the underside.
NRCA Roofing Manual: Steep-slope Roof Systems (2025), Section 4.2—Asphalt Shingle Roof System Design and Installation (Fasteners)Common-rafter slope factorvsHip-or-valley factor
The common-rafter factor converts plan run to rafter (and plan area to surface area), while the hip-or-valley factor is the larger factor used to get actual hip or valley length from the same run.
Roofing Construction & Estimating — Ch. 1, Figure 1-19 (roof-slope factors)Roof slopevsRoof pitch
Slope is expressed as rise per 12 inches of run and equals 2 × pitch (e.g., a 1/4 pitch equals a 6 in 12 slope).
Roofing Construction & Estimating, Page 1-5 (Chapter 1)DWV rough-in water testvsBuilding sewer test
The DWV water test fills each section to not less than 5 feet above the highest fitting connection, while the building sewer is pressurized to not less than a 10-foot head of water—both held not less than 15 minutes.
IRC 2018 Page 617Vertical drain offset 45 degrees or less from verticalvsStack offset more than 45 degrees above the lowest horizontal branch
An offset of 45 degrees or less from vertical is sized as a straight vertical drain, while an offset of more than 45 degrees above the lowest branch is sized as a building drain on accumulated fixture units (Table P3005.4.2).
IRC 2018 Section P3006.1SweepvsBend/elbow
A sweep is a drainage fitting with a longer turning radius than a bend, producing a less turbulent flow pattern.
IRC 2018 Section R202, DefinitionsMinimum flowing pressure for flush tank suppliesvsMinimum flowing pressure for flushometer valves and blowout fixtures
Flush tank supplies need not less than 8 psi flowing at the fixture, while flushometer valves require 15 psi and blowout-action fixtures require 25 psi.
IRC 2018 Section AP103.1CPVC pipe/tubing 1 inch and smallervsPVC pipe
CPVC 1 inch and smaller requires horizontal support at intervals not exceeding 3 feet, while PVC requires horizontal support not exceeding 4 feet.
IRC 2018 Page 621; International Plumbing Code, Page 3-4Emergency action plan for more than 10 employeesvsEmergency action plan for 10 or fewer employees
Employers with 10 or fewer employees may communicate the plan orally and need not maintain a written plan; otherwise a written plan is maintained.
OSHA 1926 CFR 29, §1926.35(e)(3)Key Terms
Danger sign OSHA 1926 CFR 29, Page 201
A construction sign having red as the predominating color for the upper panel, black outline on the borders, and a white lower panel for additional sign wording.
Fire alarm system (1926.150(e)) OSHA 1926.150(e)(1) and (e)(2)
An employer-established alarm system (e.g., telephone system, siren) whereby employees on the site and the local fire department can be alerted for an emergency, with the alarm code and reporting instructions conspicuously posted at phones and employee entrances.
Drainage fixture unit (d.f.u.) IRC 2018 Section P3004.1, Table P3004.1
A numerical factor representing the probable discharge/hydraulic load from a fixture, used per IRC P3004.1 and Table P3004.1 to compute the load on DWV piping.
Branch interval IRC 2018 Section R202, Definitions
A vertical measurement of distance, 8 feet or more in developed length, between the connections of horizontal branches to a drainage stack, measured down the stack from the highest horizontal branch connection.
Offset (piping) IRC 2018 Section R202, Definition of 'Offset'
A combination of fittings that makes two changes in direction, bringing one section of pipe out of line and into a line parallel with the other section.
Sweep IRC 2018 Section R202, Definitions
A drainage fitting that provides a change in direction of a drain pipe with a longer turning radius than a bend and a less turbulent flow pattern.
Equiviscous temperature (EVT) NRCA Roofing Manual: Membrane Roofing Systems, Chapter 5—Roof Membranes
The temperature at which a bitumen attains 125 centipoise—the optimum application temperature/viscosity—with roofing bitumen applied within 25°F of the EVT.
ASTM D3462 NRCA Roofing Manual: Steep-slope Roof Systems (2025), Section 4.1—Asphalt Shingle Standards
Standard Specification for Asphalt Shingles Made from Glass Felt and Surfaced with Mineral Granules, covering tear strength, fastener pull-through resistance, and pliability; NRCA recommends specifying fiberglass-reinforced shingles complying with it.
ASTM D1970 NRCA Roofing Manual: Steep-slope Roof Systems (2025), Section 3.1—Underlayment Materials
Standard Specification for Self-Adhering Polymer Modified Bituminous Sheet Materials Used as Steep Roofing Underlayment for Ice Dam Protection, addressing thickness, tear resistance, adhesion, low-temperature flexibility, and thermal stability.
ASTM D8257 NRCA Roofing Manual: Steep-slope Roof Systems (2025), Section 3.1—Underlayment Materials (Synthetic Sheets)
Standard Specification for Mechanically Attached Polymeric Roof Underlayments Used in Steep Slope Roofing (synthetic sheets), approved December 2020 and referenced in the 2024 IBC and IRC.
Wood boards (roof decking) NRCA Roofing Manual: Steep-slope Roof Systems (2025), Section 2.2—Wood Planks and Wood Boards
Lumber less than 2 inches thick, typically 4 to 12 inches wide; boards thinner than nominal 1 inch are not considered strong enough to support roof loads.
Panel edge clips NRCA Roofing Manual: Steep-slope Roof Systems (2025), Section 2.1—Wood Panels
Clips NRCA recommends when wood panel sheathing of ½-inch nominal thickness (actual 15/32 inch) or less is installed over supports spaced 24 inches on center.
Pipe sleeve through a foundation wall IRC 2018 Page 620; International Plumbing Code, Page 3-2
A sleeve built into the foundation wall (in lieu of a relieving arch) that must be two pipe sizes greater than the pipe passing through the wall.
Formulas to Know
Roof slope conversions (rise per 12 inches of run)
Slope = (Total Rise ÷ Total Run) × 12; also Slope = 2 × Pitch, then × 12 for rise per 12 (e.g., 7.5 ft ÷ 15 ft × 12 = 6 in 12; 1/4 pitch → 2 × 1/4 = 1/2 → 6 in 12)Actual common rafter length from plan run
Rafter length = Run × common-rafter roof-slope factor (e.g., 14 ft × 1.202 = 16.83 lin ft; 10 ft × 1.118 = 11.2 lin ft; porch 10 ft × 1.031 = 10.3 lin ft)Net (actual) roof area from plan area
Net roof area = roof plan area × roof-slope factor; ÷ 100 = squares. Take off each differently sloped section separately (e.g., 48 × 20 × 1.118 = 1,073 sq ft = 10.73 squares; porch 20 × 10 × 1.031 = 206 sq ft; 24 × 8 × 1.031 = 198 sq ft)Gable/truss geometry from span, pitch, and elevations
Run = Span ÷ 2; Rise = Run × (pitch rise ÷ 12); Ridge elevation = top-of-wall elevation + Rise; Rafter line = √(Run² + Rise²); Slope angle = arctan(Rise ÷ Run); Slope in x-in-12 = (Rise ÷ Run) × 12Hip rafter length
Actual hip length = run (half the roof width) × hip-or-valley factor (e.g., 12 × 1.732 = 20.78 ft each, ×4 = 83.1 lin ft; 10 × 1.474 = 14.74 ft each, ×4 = 59 lin ft); plan length of a hip rafter = 1.414 × run (14 ft × 1.414 = 19.80 ft)Valley length where roofs of unequal slope intersect
Actual valley length = run of the low-sloping roof × valley length factor (24 ft × 1.247 = 29.93 lin ft)Piece counts from linear feet at a given exposure
Pieces = linear feet × 12 ÷ exposure (in.), rounded up (ridge 10 ft + hips 73.4 ft = 83.4 ft × 12 ÷ 5 = 200.3 → 201 cap units; 85 ft × 12 ÷ 5 = 204 step flashings, ×1.10 waste = 224.4 → 225). Sectional stock = length ÷ section length, round up, with the stated 10% waste applied once and the result rounded up — no extra buffer piece (90 ÷ 10 = 9 → ×1.10 = 9.9 → 10 headwall sections; where waste is applied to the wall length first: 42 ft × 1.10 = 46.2 ÷ 8 = 5.78 → 6 counterflashing sections)Rolls of 15-lb felt needed
Rolls = (squares × 1.05 waste/lap allowance) ÷ 4 squares per roll, rounded up (6.50 × 1.05 = 6.82 ÷ 4 = 1.71 → 2 rolls)Labor unit price per square
Unit price = (8 hours × combined crew hourly rate) ÷ squares installed per day (8 × $35.00 = $280 ÷ 6.37 squares = $43.96 per square)Static pressure loss due to elevation in a water supply system
Loss = 0.433 psi per foot of elevation change (15 ft × 0.433 = 6.50 psi)