Exam Cheat Sheet · Quick Reference
Louisiana Residential Roofing
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
Materials
15 Q · 30%
Asphalt shingle types, components, and material standards (ASTM D3462, D3018)Underlayment types and standards for steep-slope roof systems (asphalt felt, synthetic, polymer-modified bitumen)Roof deck substrate types, requirements, and panel standards (plywood, OSB, wood planks)Clay and concrete tile types, material properties, and standards (ASTM C1167, C1492)Slate material characteristics, grades, and standards (ASTM C406)Metal shingle substrate materials and protective coatings (galvanized, Galvalume, aluminum, copper, zinc)Wood shake and wood shingle grades, species, and preservative/fire-retardant treatmentsFire classification ratings for roof assemblies (Class A, B, C) and wind-resistance classifications for roofing materials
Installation of Roof Coverings
18 Q · 36%
Asphalt shingle types, materials, and application methodsUnderlayment types, installation requirements, and slope-based configurationsRoof deck requirements and substrate types for steep-slope systemsClay and concrete tile types, materials, and fastening methodsSlate roofing materials, grades, fasteners, and installationWood shake and wood shingle materials, grading, and installationMetal shingle materials, profiles, and attachment methodsFire classification, wind resistance ratings, and IBC/IRC code compliance for roof coverings
Roof Drainage
5 Q · 10%
Primary roof drain requirements and design (IBC Section 1502)Secondary (emergency overflow) drains and scuppers — purpose, sizing, and minimum opening dimensionsGutter materials, placement, and code-required material standardsValley drainage — open, closed-cut, and no-cut valley construction and flashing requirementsDrip edge installation at eaves and rakes for steep-slope roof systemsEave details with gutters across multiple roof covering types (asphalt shingle, tile, slate, wood shake/shingle, metal shingle)Crickets and saddles — when required and drainage function at chimneys and wide penetrationsRoof slope minimums for drainage by covering type
Roofing Structures
7 Q · 14%
Roof slope measurement and calculation (rise, run, pitch, span)Roof deck types: solid vs. spaced sheathing selection by roof covering typePlywood and OSB sheathing specifications: thickness, span ratings, and rafter spacing requirementsDead loads and live loads on roof decks: design load considerations by material weightRoof framing inspection and structural integrity before re-roofingWind uplift resistance: design loads, exposure categories, and pressure zones for steep-slope roofsFORTIFIED Roof requirements: roof deck attachment, sealing, and enhanced fastening standardsRoof area measurement methods: positive/negative calculation, slope factors, hips, valleys, and ridge lengths
Safety
5 Q · 10%
Fall protection requirements for roofing work (low-slope and steep roofs)Personal fall arrest system components, specifications, and inspectionGuardrail system specifications and installation requirementsWarning line systems and safety monitoring systems for roofingLadder safety requirements, load ratings, and proper useScaffold safety requirements, capacity, and fall protection on scaffoldsPersonal protective equipment selection, use, and employer payment obligationsFire protection and prevention on construction jobsites including flammable liquid storage
Key Distinctions
Wood shingles (naturally durable wood)vsWood shakes (naturally durable wood)
Wood shingles may be Grade 1, 2, or 3 under CSSB rules, while wood shakes require a minimum of Grade 1 (taper sawn shakes allow Grade 1 or 2).
IBC 2021 Table 1507.8.5Slate shingle deck requirementvsWood shingle/shake deck requirement
Slate shingles must be fastened to solidly sheathed roofs, whereas wood shingles and shakes may use spaced sheathing (except where solid sheathing is required).
IBC 2021 Section 1507.7.1Positive measuring methodvsNegative measuring method
The positive method divides an irregular roof into rectangles and adds their areas; the negative method extends roof lines into one large rectangle and subtracts the non-roof areas — both give identical results.
Roofing Construction and Estimating, Chapter 1, Pages 7-8ASTM D7158vsASTM D3161
ASTM D7158 is a test-and-calculation procedure (assumptions from ASCE 7-22) giving basic-wind-speed classes D/G/H (90/120/150 mph), while ASTM D3161 is a fan-induced wind test giving Class A at 60 mph, Class D at 90 mph, and Class F at 110 mph.
NRCA Roofing Manual: Steep-slope Roof Systems (2025), Section 4.2—Wind Resistance (ASTM D7158—Calculation Basis)Class A roof assemblyvsClass B and Class C roof assemblies
Class A is effective against severe fire-test exposure, Class B against moderate exposure, and Class C against light exposure.
IBC 2021 Section 1505.2Nailing into wood plank/board decksvsNailing into plywood decks less than ¾ inch thick
In wood plank or board decks nails should penetrate at least ¾ inch into the deck; in plywood or other acceptable wood panel decks less than ¾ inch thick nails should 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)Plywood sheathing over rafters 16 in. o.c.vsPlywood sheathing over rafters 24 in. o.c.
NRCA recommends minimum four-ply nominal ⅝-inch (actual 19/32-inch) plywood at 16-inch spacing and nominal ¾-inch (actual 23/32-inch) plywood at 24-inch spacing for asphalt shingle systems.
NRCA Roofing Manual: Steep-slope Roof Systems (2025), Section 2.1—Wood PanelsASTM C1167vsASTM C1492
ASTM C1167 is the material standard for clay roof tile (with frost-resistance Grades 1–3), while ASTM C1492 is the standard for concrete roof tile.
IBC 2021 Section 1507.3.4ASTM D4869vsASTM D226
ASTM D4869 covers asphalt-saturated organic felt shingle underlayment (Types I–IV), while ASTM D226 applies to felts for built-up roofing and waterproofing; D4869 Type IV (#26) equals D226 Type II (No. 30 felt) and D4869 Type II (#13) equals D226 Type I (No. 15 felt).
NRCA Roofing Manual: Steep-slope Roof Systems (2025), Section 3.1—Underlayment Materials (Asphalt Felts, ASTM D4869)Self-adhering polymer-modified bitumen water/ice-dam protection sheetsvsPolymer-modified bitumen base sheets (non-self-adhering)
Self-adhering ice-dam protection sheets typically range from 20 to 60 mils thick, while non-self-adhering polymer-modified bitumen base sheets typically range from about 35 to 90 mils.
NRCA Roofing Manual: Steep-slope Roof Systems (2025), Section 3.1—Underlayment Materials (Self-adhering Polymer-modified Bitumen Sheets)Cricket at upslope side of chimneyvsBacker flashing
NRCA recommends a cricket when the chimney or curbed penetration is more than 24 inches wide; backer flashing is generally limited to penetrations 24 inches wide or less.
NRCA Roofing Manual: Steep-slope Roof Systems (2025), Asphalt Shingle Roof Systems — Chapter 7Spaced sheathing for wood shakesvsSpaced sheathing for wood shingles
Shakes normally use 1 × 6 boards (spacing equal to the shake weather exposure), while wood shingles typically use 1 × 4 boards.
Roofing Construction and Estimating, Page 30Key Terms
Class A roof assembly IBC 2021 Section 1505.2
A roof assembly effective against severe fire-test exposure; examples include minimum 16 oz/sq ft copper sheets over combustible decks and slate installed over ASTM D226 Type II underlayment over combustible decks.
Class B roof assembly IBC 2021 Section 1505.3
A roof assembly effective against moderate fire-test exposure.
Class C roof assembly IBC 2021 Section 1505.4
A roof assembly effective against light fire-test exposure.
ASTM E108 / UL 790 IBC 2021 Section 1505.1
The test standards used for Class A, B, and C roof assemblies and roof coverings required to be listed (ASTM D2898 applies additionally to fire-retardant-treated wood coverings only).
Fire-retardant-treated wood shakes and shingles IBC 2021 Section 1505.6
Wood roof coverings treated by impregnation with chemicals using the full-cell vacuum-pressure process in accordance with AWPA C1.
Solid sheathing (wood shingle/shake roofs) IBC 2021 Section 1507.8.1.1
Required decking where the average daily temperature in January is 25°F (−4°C) or less, or where ice may form along the eaves causing a backup of water.
Spaced (skip) sheathing Roofing Construction and Estimating, Page 30
Board decking under wood shakes or shingles, normally 1 × 6 boards for shakes (1 × 4 for shingles) with the board spacing equal to the weather exposure.
Wood structural panel roof sheathing exposure durability IBC 2021 Section 2304.8.2
Roof sheathing panels must be manufactured with exterior glue (Exposure 1 or Exterior).
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, ASTM D8257)
Standard Specification for Mechanically Attached Polymeric Roof Underlayments Used in Steep Slope Roofing — the standard for synthetic sheet underlayments (approved December 2020; referenced in the 2024 IBC and IRC).
ASTM D4869 NRCA Roofing Manual: Steep-slope Roof Systems (2025), Section 3.1—Underlayment Materials (Asphalt Felts, ASTM D4869)
Standard Specification for Asphalt-Saturated Organic Felt Shingle Underlayment Used in Roofing, providing four classifications (Types I–IV).
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, addressing tear strength, fastener pull-through resistance and pliability; NRCA recommends specifying fiberglass-reinforced shingles complying with it.
ASTM D3018 NRCA Roofing Manual: Steep-slope Roof Systems (2025), Section 4.1—Asphalt Shingle Standards
Standard Specification for Class A Asphalt Shingles Surfaced with Mineral Granules, addressing fire test classification, wind resistance, and loss of volatile matter after heating.
UL 2218 NRCA Roofing Manual: Steep-slope Roof Systems (2025), Section 4.1—Impact Resistance Rating
Impact Resistance of Prepared Roof Coverings, with four classes where Class 1 is the least and Class 4 the greatest measured impact resistance.
Surface Roughness B IBC 2021 Section 1609.4.2
Wind exposure surface roughness category for urban and suburban areas, wooded areas, or terrain with numerous closely spaced obstructions the size of single-family dwellings or larger (C is open terrain with scattered obstructions under 30 ft; D is flat, unobstructed areas and water surfaces).
Nesting (asphalt shingle re-cover) NRCA Roofing Manual: Steep-slope Roof Systems (2025), Asphalt Shingle Roof Systems, Chapter 6—Reroofing, Section 6.5
Application of an additional shingle layer over an existing layer where the top edge of the new shingles butts against the lower edge of the existing shingles; underlayment is not part of the re-cover system.
Formulas to Know
Roof slope and its relationship to pitch
Slope = (Total Rise ÷ Total Run) × 12, expressed as inches of rise per 12 in. of run (e.g., 8 ÷ 16 × 12 = 6 in 12); Pitch = Total Rise ÷ Total Span, and Slope = 2 × PitchRise above eave / ridge elevation
Rise = run × (slope ÷ 12), where run = span ÷ 2 (e.g., 11 ft × 6/12 = 5.50 ft = 5'-6"); Ridge elevation = top-of-wall elevation + rise (9.00' + 14.00' = 23.00')Ridge length of a conventionally framed hip roof
Ridge = L − [2 × (W ÷ 2)] = L − W (e.g., 40 − 20 = 20 lin ft; 34 − 24 = 10 lin ft)Hip rafter length
Plan length of hip = 1.414 × run (14 ft × 1.414 = 19.80 ft); actual hip length = run × hip-or-valley factor (12 ft × 1.732 = 20.78 ft each, × 4 hips = 83.1 lin ft); true hip length from 3-D runs and rise = √(run₁² + run₂² + rise²) = √(18² + 18² + 9²) = 27.00 ftActual common rafter length (eave to ridge)
Rafter length = run (half the width) × common-rafter slope factor (10 ft × 1.118 = 11.18 ft; 12 ft × 1.250 = 15.00 ft)Net (actual sloped) roof area
Sloped area = plan-view area × slope-conversion factor, taken off separately for each differing slope (24 × 10 = 240 sf × 1.014 [2:12] = 243 sf; 24 × 8 = 192 sf × 1.031 [3:12] = 198 sf; 24 × 12 = 288 sf × 1.031 = 297 sf)Shingle bundles to order
Bundles = (total sloped sf ÷ 100 squares) × 3 bundles per square × waste factor, rounded up (2,533 sf = 25.33 sq × 3 × 1.10 = 83.6 → 84 bundles; 13.86 sq × 1.05 × 3 = 43.6 → 44 bundles)Exposure-based piece/course counts
Pieces or courses = length in inches ÷ exposure in inches, rounded up: hip & ridge units = (28 ft ridge + 60.0 ft hips) × 12 ÷ 5 in = 211.2 → 212 units; courses per side = (14 × 1.031) × 12 ÷ 5 = 34.6 → 35; step flashing = 85 ft × 12 ÷ 5 = 204 pieces, or wall length ÷ 2 ft per piece (42 ÷ 2 = 21 → 22)Valley length where roofs of unequal slope intersect
Actual valley length = run of the low-sloping roof × valley length factor from Appendix B (24 ft × 1.247 = 29.93 lin ft)Roof live load reduction factors (ordinary pitched roof)
R2 = 1.0 when F ≤ 4; R2 = 1.2 − 0.05F when F is between 4 and 12 (F = 6 → 0.90); R2 = 0.6 when F ≥ 12, where F = inches of rise per foot. R1 = 1.0 when At ≤ 200 sf; R1 = 1.2 − 0.001At for At between 200 and 600 sf; R1 = 0.6 when At ≥ 600 sf