Exam Cheat Sheet · Quick Reference
Florida Roofing Contractors General Trade Knowledge Exam
Florida · Pearson Vue
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
80
Passing score
70%
Exam time
300 min
Administered by
Pearson Vue
Format
Reference materials allowed
Florida State Portion 80 questions
Built-Up Roofs
12 Q · 15%
Installation of metal gravel stops - placement, fastening requirements and techniques, adhesives requirements and techniquesPerforming test cuts - test cut requirements and techniques, when required, sizes and best method of testingBuilt-up roof surfaces - liquid applied coatings, spray polyurethanic foam, aggregates, cap sheetsTie-ins for built-up roofs - following a roofing layout, measuring for tie-ins, using cold adhesives or sprayed materialsInsulating and ventilating for built-up roofs - mechanically fastening insulation, installing multiple layer insulation, installing factory-tapered board roof insulation systems, installing field-sloped roof fill, cricketed roof fill and insulation systems, installing adhered in-place insulation, determining thermal values of roofing materials, ventilation requirements for built-up roofsRoof assembly installed over steel decks - underlayment, fastening requirements and techniques, weight and dead loads, flute span capabilities of insulationRoof assembly installed over concrete decks - weights and deadloads, underlayment requirements, adhesives requirements and techniques, fastening requirements and techniques, deck preparationRoof assembly installed over insulating concrete - weights and deadloads, fastening requirements and techniquesRoof assembly installed over wood deck - installing rosin-sized sheathing paper, weights and deadloads, underlayment requirements, adhesives requirements and techniques, fastening requirements and techniques, deck preparationInstalling coal tar pitch built-up roofing - determining roof slope, what materials can be used with coal tar, ponding, roof penetrations, sloped or tapered insulation requirementsInstalling roofing felts - surface preparation and techniques, temperature requirements, fastening requirementsInstalling flashing and counter-flashing for built-up roofs - metal flashings, reinforced membrane flashings, flashing around penetrations, crickets and saddle flashings
+8 more
Shingles and Shakes
12 Q · 15%
Selecting appropriate type of shingles - types available, different types and compatibility, number of bundles per square, exposure requirements, approximate coverage, roof deck requirements for application of wood shingles and wood shakes, fastening requirements and techniquesCutting shingles individually when using a pattern - cutting tools, measuring for cuttingUsing the straight-up method - marking and following bond lines, shingling around obstructionsUsing the stair stepping method - applying strips of underlayment, overlapping measurementsStraightening bond lines - marking and following bond lines, even and uneven lines, shingling around penetrations or obstructionsInstalling wood shakes - doubling at all eaves, starter course placement, gutter requirements, trough requirements, shingle extension, spacing between adjacent shingles, nailing and fastening, attaching hip and ridge shingles, pre-manufactured hip and ridge unit application, preparing areas to be shingled, handling shingles, roofing underlaymentsDetermining fastener types, placement and length for wood shakes and shingles - types of fasteners and their application, spacing for different types of shingles, types of nails, size of nails needed and requiredDetermining width and grade for wood shakes - types of grades and when applicableDetermining shingle and shake exposure - slope calculations, coverage of one square of shingles based on following weather exposures, types of shingles and shakes and their properties, spacing requirementsInstalling composite shingles - adhesive requirements, live loads, cutting, placement, roof recover requirements, surface preparation requirementsTie-ins for shingles and shakes - following a roofing layout, methods and materials for tie-insInstalling valleys - methods of installation, placing shingles appropriately, plastic cement, valley underlayments, adhesive requirements, fastening requirements and techniques, underlayment, trimming or dub corners, verifying and selecting proper materials, waterproofing blind/dead valleys, connecting valleys
+11 more
Architectural Metal Roofs
8 Q · 10%
Installing architectural metal roofs - fasteners, caulk, adhesives, soldering, flashing, underlayment, wind loads, use of dissimilar materialsTie-ins for architectural metal roofs - following a roofing layout, measuring for tie-ins, using metal flashingsInstalling metal shingles - placement, fastening requirements and techniques, adhesive requirements, sealantsInsulating and ventilating for architectural metal roofs - mechanically fastening insulation, determining thermal values of roofing materials, ventilation requirements for architectural metal roofsInstalling flashing and counter-flashing for architectural metal roofs - metal flashings, reinforced membrane flashings, flashing around penetrations, crickets and saddle flashingsMaintenance and repair of architectural metal roofs - determine roof assembly and condition, leak detectionMetal types and material properties - naturally weathering metals, metallic-coated metals, and protective coatingsGalvanic corrosion and dissimilar metal compatibility - galvanic scale, isolation methods, and runoff concernsThermal expansion and contraction - coefficients of expansion by metal type and design accommodations for movementOil canning - causes, prevention, and panel design considerationsMetal panel system types - architectural vs. structural panels, seam types, profiles, and minimum slope requirementsFlorida Building Code and HVHZ requirements for metal roofing - product approval, testing standards (TAS 125, RAS 133), and wind-driven rain resistance
+2 more
Single Ply Systems
12 Q · 15%
Installing adhesive-applied systems - adhesives and their properties, effects of sunInstalling heat applied systems - heat application equipment, application temperaturesInstalling mechanically fastened systems - fastening requirements and techniques, sealant requirements and techniquesTie-ins for single-ply roofs - following a roofing layout, methods and materials for Tie-insDetermining seaming needs - types of seaming adhesive and their properties, application requirements and techniques, seaming tapes, heat seaming methodsInsulating and ventilating - installing insulation, installing factory-tapered board roof insulation systems, installing field-sloped and cricketed roof fill and insulation systems, determining thermal values of roofing materials, ventilation requirements for single ply roofsInstalling flashing and counter-flashing - metal flashings, supported and unsupported membrane flashings, flashing around penetrations, crickets and saddle flashingsMaintenance and repair - determine roof assembly and condition, leak detectionSingle-ply membrane types and material standards - EPDM, TPO, PVC, CSPE, KEE and their ASTM standardsWind uplift resistance and field testing - design pressure requirements, TAS 124 field uplift testing procedures, ASCE 7 complianceRoof deck types and compatibility with single-ply systems - steel, concrete, nailable decks, deck preparation requirementsAir and vapor retarders in single-ply assemblies - placement, materials, condensation control for low-slope systems
+4 more
Modified Roofing Systems
12 Q · 15%
Installing modified systems - asphalt properties, sealants and caulks, APP modified, SBS modified, SA modifiedInstalling adhesive-applied systems - adhesives and their properties, effects of sun, application methodsInstalling heat applied systems - heat application equipment, application temperaturesInsulating and ventilating - installing insulation, installing factory-tapered board roof insulation systems, installing field-sloped and cricketed roof fill and insulation systems, determining thermal values of roofing materials, ventilation requirements for modified roofing systemsInstalling flashing and counter-flashing - metal flashings, reinforced membrane flashings, flashing around penetrations, crickets and saddle flashingsRoof deck types and their compatibility with modified bitumen systems - steel, concrete, nailable, and nonnailable decksWind uplift resistance requirements for modified roofing assemblies - field, perimeter, and corner zonesReroofing over existing systems - re-cover versus tear-off criteria, evaluation of existing roof conditions, and code requirementsFire classification requirements for modified bitumen roof assemblies under FBC and NRCA standardsFBC HVHZ requirements for modified bitumen systems - product approval, asphalt type and temperature criteria, base sheet attachmentInsulation fasteners and attachment patterns - mechanical attachment to steel, concrete, and wood decks under RAS 117Physical property testing standards for modified bitumen membranes and components - ASTM standards and TAS 110 requirements
Concrete and Clay Tile Roofs
8 Q · 10%
LoadsRoof Layout Bond linesAdhesive requirementsInstalling flashing and counter-flashing for concrete and tile roofs - metal flashings, reinforced membrane flashings, flashing around penetrations, crickets and saddle flashingsUnder tile drainage requirementsPlastic cement application requirementsMortar applicationsBattensFastening requirementsRidge and hip tilesGables and perimetersFoam
+12 more
Membrane Waterproofing
4 Q · 5%
Installation of walls below grade - materials, primers, different membrane types, hydrostatic pressure, hot and cold application methods, when membrane waterproofing is requiredInstallation of floor slabs - materials, primers, different membrane types, hydrostatic pressure, hot and cold application methods, when membrane waterproofing is requiredPositive vs. negative (interior) side waterproofing - definitions, design implications, and when each is appropriateDrainage systems and geocomposites - perimeter drains, drainage mats, bi-level deck drains, and hydrostatic pressure reliefWaterproofing system accessory materials - protection courses, waterstops, and prefabricated drainage productsMembrane integrity testing - flood test, flowing-water test, and electronic leak detection (ELD) methodsBlind-side waterproofing - applications, substrates, shoring wall requirements, and installation sequencingFlashing requirements - membrane flashings, sheet-metal counterflashings, termination heights, penetration clearances, and expansion jointsWaterproofing repair and maintenance - chemical grout injection, crystalline repair, acrylamide gel injection, and bentonite grout injectionDampproofing vs. waterproofing - definitions, appropriate applications, solvent-based and bituminous-emulsion dampproofing products and installation
Drain and Gutters
4 Q · 5%
Verifying scupper overflow requirements - water flow ratesDetermining gutter and downspout requirements - water flow ratesInstalling gutters and downspouts - strapping, fastening requirements and techniques, size requirementsInstalling leader and conductor heads - fastening requirements and techniques, caulk and sealants, size requirementsGutter expansion joint types and installation - lap, butt, and built-in joint configurationsGutter material selection and minimum gauge requirements by girthRoof rain load design requirements and ponding instability considerationsSecondary overflow drain and scupper inlet elevation placement requirementsDownspout hanger types and maximum spacing intervalsRoof sump and splash pan installation requirements
Equipment and Safety
8 Q · 10%
Using ladders - safety requirements, OSHA requirementsUsing scaffolds - safety requirements, OSHA requirementsUsing hoists (manual and automatic) - safety requirements, OSHA requirements, load capabilitiesUsing lift trucks - safety requirements, OSHA requirements, load capabilitiesUsing kettles - safety requirements, OSHA requirements, tar temperature, temperature gauges and automatic controls, starting proceduresUsing heat welding equipment - safety requirements, OSHA requirements, torches, hot airUsing manual lifts - safety requirements, OSHA requirements, load capabilitiesUsing pump lifts - safety requirements, OSHA requirements, dynamic heads, mechanical jointsUsing roof jacks for steep pitch - safety requirements, OSHA requirements, proper anchoring proceduresUsing spudding machines - safety requirements, OSHA requirements, aggregate disposalUsing compressors - safety requirements, OSHA requirementsUsing pneumatic equipment - safety requirements, OSHA requirements, pressure requirements, fastening requirements and techniques
+9 more
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 into one large rectangle and subtracts the areas that are not roof; both yield identical results.
Roofing Construction and Estimating, Chapter 1, Pages 7-8Minimum design slope for new constructionvsMinimum design slope for reroofing (re-cover or tear-off and replacement)
New construction must meet specific minimum slopes depending on membrane type, but for reroof re-cover or replacement the codes do not require the new system to meet minimum design slope provided there is positive roof drainage.
NRCA Roofing Manual: Membrane Roof Systems, Chapter 2, Page 84Tile assembly with single layer of mechanically attached underlaymentvsTile assembly with self-adhering or double-layer underlayment
The single-layer mechanically attached configuration requires a minimum 4:12 slope per IBC/IRC (NRCA also recommends 4:12), while self-adhering or double-layer underlayment configurations permit a minimum 2½:12 per IBC/IRC.
NRCA Roofing Manual: Steep-slope Roof Systems (2025), Clay and Concrete Tile Roof Systems, Chapter 1—Roof Assembly Configurations, Single-layer Underlayment Mechanically AttachedFiberglass 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.
NRCA Roofing Manual: Architectural Metal Flashing Condensation and Air Leakage Control, and Reroofing, Appendix 6—Climatic Design Information (glossary, "asphalt shingle")Thermal resistance (R) valuesvsThermal conductance (C) factors, conductivity (k) and transmittance (U)
R-values of multiple insulation layers can be mathematically added (Rt = R1 + R2 + ...), while C-factors, k-values and U-values cannot be added — C-factors must first be converted to R (R = 1/C).
NRCA Roofing Manual: Membrane Roof Systems (2023), Chapter 4, Section 4.1 — Principles of Thermal InsulationCoarse aggregate backfill used to relieve hydrostatic pressurevsPrefabricated geocomposite drainage product
When aggregate relieves pressure a separate protection course must be placed against the waterproofing membrane (loose aggregate must never contact the membrane), whereas some geocomposites both relieve pressure and protect the membrane, eliminating the need for a separate course.
NRCA Waterproofing Manual, 2nd ed., Section 2.2.1 — Geocomposites (Drainage mat)Flat seams sealed with sealantvsFlat seams soldered
Flat seam joints may be sealed with sealant except where the pitch is less than 3 in. per ft, which requires soldering; in snow areas all seams subject to flooding from ice damming must be soldered regardless of pitch.
SMACNA Architectural Sheet Metal Manual (7th ed.), Flat Seam Roofs, Figure 6-3Woodblocking anchor withdrawal resistance on lightweight decks (HVHZ)vsCounter-flashing and termination bar anchor values
Lightweight decks may serve as woodblocking attachment substrate only if the anchor achieves an average withdrawal resistance of not less than 450 lbf per TAS 105 (or the anchor is fastened to the deck underside or a structural member); the 150 lbf and 180 lbf figures apply to counter-flashing and termination bar anchors, not woodblocking.
Florida Building Code – Test Protocols for HVHZ, RAS No. 111-20, Section 3.8.2 (Woodblocking Attachment, Lightweight Decks)Danger signsvsCaution signs
Danger signs shall be used only where an immediate hazard exists (red upper panel, black border outline, white lower panel for wording), while caution signs are used to warn against potential hazards or to caution against unsafe practices.
OSHA 1926 CFR 29, §1926.200(b)(1)Fire extinguisher rated not less than 2AvsFire extinguisher rated not less than 10B
A 2A-rated extinguisher is required for each 3,000 sq ft of protected building area (or major fraction) with travel distance not exceeding 100 feet, while a 10B-rated extinguisher must be within 50 feet wherever more than 5 gallons of flammable/combustible liquid or 5 pounds of flammable gas are in use.
OSHA 1926.150(c)(1)(i)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 mils to 60 mils thick, while non-self-adhering polymer-modified bitumen base sheets typically range from about 35 mils up to 90 mils.
NRCA Roofing Manual: Steep-slope Roof Systems (2025), Section 3.1—Underlayment Materials (Self-adhering Polymer-modified Bitumen Sheets)ASTM D4869vsASTM D226
ASTM D4869 covers asphalt-saturated organic felt shingle underlayment used in roofing (Types I–IV), while ASTM D226 applies to felts for built-up roof systems and waterproofing, although its designations remain commonly used in the industry.
NRCA Roofing Manual: Steep-slope Roof Systems (2025), Section 3.1—Underlayment Materials (Asphalt Felts, ASTM D4869)Key Terms
Competent person OSHA 1926 CFR 29, §1926.32(f), Page 31
Per 29 CFR 1926.32(f), one who is capable of identifying existing and predictable hazards in the surroundings or working conditions which are unsanitary, hazardous, or dangerous to employees and who has authorization to take prompt corrective measures to eliminate them (no specific degree, experience or certificate is required); competent persons designated by the employer must also make the frequent and regular job site, material and equipment inspections required by §1926.20(b)(2).
Perm NRCA Roofing Manual: Architectural Metal Flashing Condensation and Air Leakage Control, and Reroofing, Appendix 6—Climatic Design Information
One perm is the transmission of 1 grain (about 0.07 grams) of water vapor per square foot per hour per each inch of mercury vapor pressure difference across the barrier; the lower the perm rating, the better the vapor barrier.
Effective vapor retarder (roof assemblies) NRCA Roofing Manual: Architectural Metal Flashing, Condensation and Air Leakage Control, and Reroofing — Condensation and Air Leakage Control, Chapter 1, Page 213
NRCA recommends a material or construction have a perm rating of 0.5 or less to be considered an effective vapor retarder for roof assemblies (by comparison, IBC/IRC Class I is 0.1 perm or less and Class II is 1.0 perm or less but greater than 0.1).
Impermeable synthetic sheet underlayment NRCA Roofing Manual: Steep-slope Roof Systems (2025), Section 3.1—Underlayment Materials (Synthetic Sheets)
A synthetic underlayment with a water vapor transmission rating of less than 0.1 perms; NRCA recommends against specifying these over unvented or inadequately ventilated attics.
Equiviscous temperature (EVT) NRCA Roofing Manual: Membrane Roofing Systems, Chapter 5—Roof Membranes
The temperature at which a bitumen attains 125 centipoise — the optimum temperature and viscosity for application so it sticks properly and is waterproof; roofing bitumen should be applied within 25°F of the EVT.
Oil canning / tension precision leveling NRCA Roofing Manual: Metal Panel and SPF Roof Systems (2024), Pages 95-96 (Chapter 4, Section 4.4—Oil Canning)
Oil canning is waviness in metal panels that NRCA suggests reducing by specifying tension precision-leveled coil stock — coil stretched beyond its yield point to produce a level surface — done after secondary coil operations such as slitting of a master coil.
Interlayment (lacing) NRCA Roofing Manual: Steep-slope Roof Systems (2025), Wood Shake and Wood Shingle Roof Systems, Chapter 1—Roof Assembly Configurations
A course of felt installed with every course of wood shakes that acts as a baffle to keep wind-driven snow or other foreign material out of the attic cavity and increases insulating value; with continuous sheathing it completes three layers of water-shedding coverage in the field of the roof.
Built-in gutter (low-slope roof) SMACNA Architectural Sheet Metal Manual (7th ed.), Page 1.16
A gutter whose highest point on the front must be a minimum of 1 in. (25 mm) lower than the back edge so overflow water spills over the front rather than into the building.
Polyisocyanurate design R-value NRCA Roofing Manual: Membrane Roof Systems (2023), Chapter 4—Rigid Board Insulation, Section 4.9—Polyisocyanurate, Page 159
NRCA does not consider the LTTR-predicted five-year R-value or 15-year time-weighted average suitable for design purposes and recommends specifying polyisocyanurate based on an in-service R-value of 5.0 per inch, specified by thickness rather than by R-value.
Thermal-setting insulating fill NRCA Roofing Manual: Membrane Roof Systems (2023), Section 9.4—Roof Decks for Reroofing (Thermal-setting Insulating Fill), Page 297
Perlite aggregate mixed with hot asphalt binder that is screeded and usually roller-compacted to about two-thirds of its applied thickness to provide slope for drainage, with proper compaction producing a density of 18 to 22 pounds per cubic foot; it is a non-nailable substrate requiring an adhered base or separator sheet.
Aerodynamic multiplier (λ) Florida Building Code Roofing Application Standard (RAS) No. 127-20, Section 2.2
A tile-specific value the contractor must obtain from the tile Product Approval when computing the moment of resistance for each roof pressure zone; design wind pressures come from the RAS 127 tables or a sealed engineering analysis, while λ, the restoring moment due to gravity and attachment resistance all come from the Product Approval.
Type M roof tile mortar Florida Building Code Roofing Application Standard (RAS) No. 119-20, Section 2.05
Sand/cement mortar for mortar-set tile, whether job mixed or premixed, meeting the ASTM C270 Type M requirement of 2.25 to 2.5 parts sand to 1 part cement; lightweight aggregate/cement mortar must be premixed and bagged.
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 sheet underlayments), originally approved December 2020 and referenced in the 2024 IBC and IRC.
ASTM D6694 NRCA Roofing Manual: Metal Panel and SPF Roof Systems (2024), SPF Roof Systems, Chapter 6—Protective Surfacings, Pages 438-440
Specification for Liquid-Applied Silicone Coating Used in Spray Polyurethane Foam Roofing — the specification silicone protective coatings over SPF should comply with (ASTM D6083 covers acrylic, D6947 covers moisture-cured polyurethane, D1653 is a water-vapor-transmission test method).
Emergency action plan (OSHA §1926.35) OSHA 1926 CFR 29, §1926.35(b), Page 33
A plan whose minimum elements are emergency escape procedures, procedures for employees remaining for critical operations, procedures to account for all employees after evacuation, rescue and medical duties, preferred means of reporting emergencies, and names/titles of contact persons (a tool and equipment inventory is not required); employers with 10 or fewer employees may communicate it orally and need not maintain a written plan.
Formulas to Know
Labor unit price per square
(crew hourly rate total × 8 hours) ÷ daily crew production in squares; e.g., ($25.00 + $10.00) × 8 = $280.00 ÷ 6.37 sq = $43.96 per square (Equation 14-1)Material allowance factor (waste and lapping)
Allowance factor = gross area ÷ net area; e.g., 13.8 squares ÷ 12 squares = 1.15 = 15 percent allowance (Equation 1-12)Plan length of a hip or valley framed at 45 degrees
Plan length = 1.414 × run; e.g., 1.414 × 14 ft = 19.80 ft; 1.414 × 16 ft = 22.62 ft (actual rafter length is then found by applying the column 4 slope factor to the plan length)Ridge length of a conventionally framed hip roof
Ridge = length − width; e.g., 50 ft − 24 ft = 26 lin ft (Equation 1-15)Valley length where roofs of unequal slope intersect
Actual valley length = run of the low-sloping roof × valley length factor from Appendix B; e.g., 24 ft × 1.247 = 29.93 lin ftRafter / roof surface length from slope factor, and rise
Rafter length = run × slope (common-rafter) factor, with any horizontal overhang added to the run before multiplying: (14 + 2) × 1.202 = 19.2 ft; (18 + 1) × 1.250 = 23.8 ft; 24 × 1.118 = 26.8 ft. Run = span ÷ 2; Rise = (pitch ÷ 12) × run, e.g., (3 ÷ 12) × 16 = 4'-0" (Equation 1-4)Number of shingle courses at a given exposure
Courses = (rafter length in ft × 12) ÷ exposure in inches, rounded up; e.g., 21.66 ft × 12 = 259.9 in ÷ 5 in = 52 courses (Equation 4-3)Roof area in squares and material counts by coverage
Squares = total area ÷ 100 (positive method: 140 × 60 + 50 × 20 = 9,400 sq ft ÷ 100 = 94.00 squares; no slope factor on a low-slope roof); rolls = area ÷ net coverage per roll (6,800 ÷ 100 = 68 rolls); boards = area ÷ 32 sq ft per 4 × 8 board (6,800 ÷ 32 = 212.5 → 213); aggregate weight = squares × lb per square (68.00 × 300 lb slag = 20,400 lb); metal sheets from 36 × 120 in stock = count strips cut across the 36-in width, since offcuts smaller than the girth are unusable — 24-in girth yields 1 strip = 10 lin ft per sheet, so 240 lin ft ÷ 10 = 24 sheets (the flat-area method 480 ÷ 30 = 16 undercounts); 9-in girth: 80 × 0.75 = 60 sq ft ÷ 30 = 2 sheets — always round upFlashing piece counts with exposure and waste
Step flashing pieces = (wall length in ft × 12) ÷ exposure in inches, rounded up; add waste only if specified (85 ft: 1,020 in ÷ 5 in = 204 → ×1.10 = 224.4 → 225 pieces; 42 ft: 504 in ÷ 5 in = 100.8 → 101 pieces). Sectional flashing: apply the 10% waste factor once, then round up to whole sections (42 ft × 1.10 = 46.2 ft ÷ 8 ft = 5.78 → 6; 90 ft ÷ 10 ft = 9 × 1.10 = 9.9 → 10).Gutter cross-section, drain sump size, and pitched-roof design area
Gutter cross-section = (roof sq ft × rainfall in/hr) ÷ 100 sq ft per sq in at 1 in/hr; e.g., 5,000 × 6 ÷ 100 = 300 sq in. Minimum drain sump = drain bowl diameter + 24 in each way; e.g., 12 + 24 = 36 in × 36 in. Pitched-roof design area = plan area × Table 1-1 factor (1.20 for 9 to 11 in. per ft).