Types

• Asphalt Shingle Roofing
  Fiberglass-mat asphalt shingles with mineral granules, laid over underlayment on sloped decks, used as the most common residential roof covering.
• Built-Up Roofing
  Multiple plies of bitumen-saturated felt set in hot asphalt or coal tar and surfaced with gravel or coatings, used on low-slope roofs needing redundancy and durability.
• Clay and Concrete Tile Roofing
  Fired clay or extruded concrete roof tiles laid over underlayment on sloped decks, used for durable, fire-resistant roofs in warm and Mediterranean-style architecture.
• EPDM Roofing
  Synthetic rubber single-ply membrane with taped or adhesive seams, used on low-slope roofs for durability, flexibility, and low cost.
• Modified Bitumen Roofing
  Multi-ply roofing of polymer-modified asphalt sheets, SBS or APP, applied by torch, hot asphalt, cold adhesive, or self-adhesion, used on low-slope roofs needing redundancy and toughness.
• PVC Roofing
  Heat-welded polyvinyl chloride single-ply membrane, used on low-slope roofs needing chemical, grease, and fire resistance, including restaurants and hospitals.
• Roof Drainage Systems
  Roof drains, scuppers, gutters, leaders, and overflow systems, with tapered slope and crickets, used to remove rainwater from roofs and prevent ponding and overload.
• Skylights and Roof Windows
  Glazed roof openings, including curb- and deck-mounted unit skylights, venting roof windows, and tubular daylighting devices, used to bring daylight and ventilation through roofs.
• Slate Roofing
  Natural stone roofing slate cut into shingles and fastened in overlapping courses on a solid deck, graded by ASTM C406.
• Standing Seam Metal Roofing
  Concealed-fastener metal roof panels joined by raised vertical seams and held by clips, used on steep- and low-slope commercial and residential roofs.
• TPO Roofing
  Heat-welded thermoplastic polyolefin single-ply membrane, usually white, used on low-slope commercial, industrial, and multifamily roofs.
• Vegetated Roofs
  Roof assemblies with waterproofing, drainage, growing medium, and plants, used for stormwater retention, heat reduction, amenity space, and membrane protection.
• Wall and Roof Insulation
  Thermal insulation in batt, blown, rigid board, and spray foam forms that slows heat flow through walls and roofs.

Code reference

Always verify the adopted code edition and local amendments for the project jurisdiction.

Governing editions

Drainage

• IBC 2024, Section 1502.1: roof drainage designed per Section 1502, Section 1611, and IPC Chapter 11 (roof drainage systems)
• IBC 2024, Section 1502.2: secondary (emergency overflow) roof drains or scuppers where the roof perimeter extends above the roof so water would be trapped if primary drains are blocked (roof drainage systems)
• IBC 2024, Section 1502.3: exterior gutters and leaders noncombustible or at least Schedule 40 plastic pipe, with listed exceptions (roof drainage systems)
• IBC 2024, Section 1603.1.9: construction documents show design rainfall intensity and roof drain, scupper, and overflow locations (roof drainage systems)
• IBC 2024, Section 1604.3: roofs without sufficient slope or camber investigated for ponding per ASCE 7 Chapter 8
• IPC 2024, Chapter 11: storm drainage sizing for primary and secondary roof drains (roof drainage systems)

Weather protection and flashing

• IBC 2024, Sections 1503.2 and 1503.2.1: flashing to prevent water entry at copings, wall and roof intersections, gutters, changes of slope, and roof openings and penetrations; metal flashing corrosion resistant, at least 0.019 in. (No. 26 galvanized sheet)
• IBC 2024, Section 1503.3: parapet walls coped or covered, with the top providing positive drainage
• IBC 2024, Section 1503.5: crickets or saddles on the ridge side of any chimney or penetration wider than 30 in.

Wind and physical performance

• IBC 2024, Section 1504.2 and Table 1504.2: asphalt shingles tested to ASTM D7158, or ASTM D3161 where outside D7158 scope, with class by basic wind speed (asphalt shingle roofing)
• IBC 2024, Section 1504.3: clay and concrete tile wind loads per Section 1609.6; testing per SBCCI SSTD 11 or ASTM C1568 (overturning), ASTM C1569 (wind tunnel), and ASTM C1570 or default lift coefficient (clay and concrete tile roofing)
• IBC 2024, Section 1504.4: mechanically attached and adhered coverings resist components and cladding pressures per Section 1609.6.2
• IBC 2024, Section 1504.4.1: built-up, modified bitumen, single-ply, and similar membranes tested to FM 4474, UL 580, or UL 1897 (TPO, PVC, EPDM, modified bitumen, built-up roofing)
• IBC 2024, Section 1504.4.2: structural standing seam metal panels tested to ASTM E1592 or FM 4474; through-fastened panels may use UL 580 (standing seam metal roofing)
• IBC 2024, Section 1504.5: ballasted single-ply roofs designed per ANSI/SPRI RP-4 (TPO, PVC, EPDM roofing)
• IBC 2024, Section 1504.6: low-slope metal edge systems designed for wind per Chapter 16 and tested to ANSI/SPRI ES-1 (RE-1, RE-2, RE-3); gutters that secure membrane edges tested to SPRI GT-1 per 1504.6.1
• IBC 2024, Section 1504.7: low-slope coverings resist impact per ASTM D3746, ASTM D4272, or FM 4470
• IBC 2024, Section 1504.8 and Table 1504.8: aggregate-surfaced roofs need perimeter parapets of height set by mean roof height, wind speed, exposure, and aggregate size; ballasted single-ply excepted (built-up roofing)

Fire classification

• IBC 2024, Section 1505.1 and Table 1505.1: minimum roof assembly classification by construction type; Class A, B, and C tested to ASTM E108 or UL 790
• IBC 2024, Section 1505.2: Class A roof assemblies permitted on all construction types
• IBC 2024, Section 1505.9: rooftop PV panel systems classified per UL 2703 and meet Table 1505.1
• IBC 2024, Section 1505.10: vegetative roofs comply with Section 1505.1 and Section 1507.15 and are installed per ANSI/SPRI VF-1 (vegetated roofs)

Roof coverings

• IBC 2024, Section 1507.1.1: underlayment required under asphalt shingles, tile, metal shingles and panels, slate, wood, and BIPV, per Tables 1507.1.1(1) to (3)
• IBC 2024, Section 1507.1.2: ice barrier where ice has historically backed up at eaves: two cemented underlayment layers or self-adhering polymer-modified bitumen, extending 24 in. inside the exterior wall line (asphalt shingle, tile, metal roofing)
• IBC 2024, Section 1507.2: asphalt shingles: minimum slope 2:12; double underlayment from 2:12 to less than 4:12; shingles per ASTM D3462; nails per ASTM F1667; at least four fasteners per strip shingle (asphalt shingle roofing)
• IBC 2024, Section 1507.3: clay and concrete tile: minimum slope 2-1/2:12; double underlayment from 2-1/2:12 to less than 4:12; solid sheathing (spaced lumber allowed in Seismic Design Categories A, B, and C); clay tile per ASTM C1167, concrete tile per ASTM C1492 (clay and concrete tile roofing)
• IBC 2024, Section 1507.4: metal roof panels: minimum slope 3:12 for lapped, nonsoldered seams without sealant; 1/2:12 with applied sealant; 1/4:12 for standing seam systems; materials per Table 1507.4.3 (standing seam metal roofing)
• IBC 2024, Section 1507.7: slate shingles: roofing slate per ASTM C406 (1507.7.5); fastened to a solidly sheathed roof (1507.7.1); two fasteners per slate and headlap by slope, 4 in. for slopes of 4:12 to 8:12 (1507.7.6, from a Massachusetts adoption of the 2024 text) (slate roofing)
• IBC 2024, Section 1507.10: built-up roofs: minimum slope 1/4:12, or 1/8:12 for coal-tar systems; materials per Table 1507.10.2 or UL 55A (built-up roofing)
• IBC 2024, Section 1507.11: modified bitumen: minimum slope 1/4:12; sheets per ASTM D6162, D6163, D6164, D6222, D6223, D6298, or D6509 (modified bitumen roofing)
• IBC 2024, Section 1507.12: single-ply roofing: minimum slope 1/4:12; EPDM per ASTM D4637, PVC per D4434, KEE per D6754, TPO per D6878, CSPE or PIB per D5019 (TPO, PVC, EPDM roofing)
• IBC 2024, Section 1507.15: vegetative and landscaped roofs comply with Chapter 15, the structural live load provisions of Chapter 16, and the International Fire Code (vegetated roofs)

Roof insulation and rooftop structures

• IBC 2024, Section 1508: above-deck insulation covered by an approved roof covering and tested as an assembly to NFPA 276 or UL 1256; foam plastics per Chapter 26; boards per Table 1508.2 (wall and roof insulation) (ASTM C1289 polyiso, C578 polystyrene, C728 perlite, C552 or C1902 cellular glass, C726 mineral fiber, C208 wood fiberboard)
• IBC 2024, Section 1510: radiant barriers above the deck covered by an approved roof covering and tested to FM 4450 or UL 1256
• IBC 2024, Section 1511: penthouses and enclosed rooftop structures limited to one-third of the roof area; 18 ft maximum height above the roof deck except Type I; 28 ft for tank and elevator enclosures; uses limited to equipment, tanks, elevators, stairways, and shafts

Reroofing

• IBC 2024, Section 1512.2: roof replacement removes all existing layers down to the deck, with exceptions for adhered ice barriers and self-adhered underlayment
• IBC 2024, Section 1512.3: recovering permitted per manufacturer's instructions; complete standing seam metal systems may go over existing coverings without removal; metal, concrete, and clay tile allowed over wood shakes per Section 1512.3.1

Energy

• IECC 2024, Section C402: roof insulation (R-value or U-factor), skylights, and air leakage for the building thermal envelope

Referenced standards

Sources

• UpCodes: 2024 IBC Chapter 15 roof assemblies and rooftop structures (Department of Defense adoption), Chapter 15 Roof Assemblies and Rooftop Structures: Department of Defense Building Code 2024 | UpCodes
• UpCodes: 2024 IBC Chapter 16 structural design, https://up.codes/viewer/department-of-defense/ibc-2024/chapter/16/structural-design
• Professional Roofing: designing roof drains, https://professionalroofing.net/articles/article/5770
• Professional Roofing: understanding asphalt shingle standards, https://professionalroofing.net/articles/article/4817
• SPRI: standards, https://www.spri.org/
• NRCA: technical resources, https://www.nrca.net/