1 Scope
NOTE This specification covers the materials, fabrication, attachment, and installation of cold-formed steel deck used as a structural floor or roof element in buildings and structures. (1.1)
NOTE Steel deck under this specification serves one or more of three structural functions: as a permanent form and tensile reinforcement for a structural concrete slab (composite floor deck); as a permanent stay-in-place form for a concrete slab in which the deck is not relied upon for composite action (non-composite form deck); and as a roof deck supporting roofing membranes, insulation, and superimposed live and dead loads. (1.2)
1.3 In all three functions the deck may also act as a horizontal diaphragm transferring lateral loads to the building's vertical lateral force-resisting system.
NOTE Steel deck is procured by profile, depth, gauge, finish, and length, but it is structurally meaningful only when correctly attached. (1.4)
NOTE The same deck panel with two different fastening patterns produces dramatically different shear capacity, uplift resistance, and composite or diaphragm behavior. (1.5)
1.6 This specification governs both the deck product and the fastening pattern that makes the deck perform as designed; both shall be installed in accordance with the contract drawings and the approved shop drawings.
1.7 Design, materials, fabrication, and installation shall conform to the Steel Deck Institute (SDI) standards applicable to the deck function — SDI C-2017 (Standard for Composite Steel Floor Deck-Slabs), SDI NC-2017 (Standard for Non-Composite Steel Floor Deck), and SDI RD-2017 (Standard for Steel Roof Deck) — together with SDI MOC3 (Manual of Construction with Steel Deck), AISI S100 (North American Specification for the Design of Cold-Formed Steel Structural Members), and AISI S310 (North American Standard for the Design of Profiled Steel Diaphragm Panels).
1.8 Diaphragm design shall additionally comply with SDI DDM04 (Diaphragm Design Manual, 4th Edition) where the deck is relied upon for diaphragm action.
1.9 Deck profile, depth, gauge, finish, span direction, side-lap orientation, panel layout, support fastener pattern, side-lap fastener pattern, and the locations and details of openings, sumps, ridge plates, valley plates, and pour stops are as indicated on the structural framing plans, roof framing plans, deck layout drawings, and structural details. 1.10 Where this specification and the contract drawings differ, the more stringent requirement governs; the Structural Engineer of Record (SER) shall resolve genuine conflicts in writing.
1.11 Exclusions
NOTE This specification does not cover hot-rolled structural steel framing (see
Structural Steel Framing), open-web steel joists and joist girders (see
Steel Joists), the design and placement of the concrete fill or topping placed over composite or non-composite deck (see
Cast In Place Concrete), reinforcement furnished within the concrete fill or topping (see
Concrete Reinforcement), or spray-applied fireproofing applied to the underside of the deck (see
Fireproofing).
(1.11.1) NOTE Roofing membranes, insulation boards, and roof cover boards installed above the roof deck are covered by the roofing specifications. (1.11.2)
2 Referenced Standards
| Standard |
Title |
| SDI C-2017 |
Standard for Composite Steel Floor Deck-Slabs |
| SDI NC-2017 |
Standard for Non-Composite Steel Floor Deck |
| SDI RD-2017 |
Standard for Steel Roof Deck |
| SDI MOC3 |
Manual of Construction with Steel Deck (3rd Edition) |
| SDI DDM04 |
Diaphragm Design Manual (4th Edition) |
| SDI T-CD |
Test Standard for Composite Steel Deck-Slabs |
| AISI S100-16 (R2020) |
North American Specification for the Design of Cold-Formed Steel Structural Members |
| AISI S310-20 |
North American Standard for the Design of Profiled Steel Diaphragm Panels |
| ANSI/AISC 360-22 |
Specification for Structural Steel Buildings (composite slab provisions) |
| AWS D1.3/D1.3M:2018 |
Structural Welding Code — Sheet Steel |
| AWS D1.1:2025 |
Structural Welding Code — Steel (where structural welds to supports are involved) |
| ASTM A653/A653M |
Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process |
| ASTM A1008/A1008M |
Standard Specification for Steel, Sheet, Cold-Rolled, Carbon, Structural, High-Strength Low-Alloy, and High-Strength Low-Alloy with Improved Formability, Solution Hardened, and Bake Hardenable |
| ASTM A370 |
Standard Test Methods and Definitions for Mechanical Testing of Steel Products |
| ASTM E108 |
Standard Test Methods for Fire Tests of Roof Coverings |
| ASTM E119 |
Standard Test Methods for Fire Tests of Building Construction and Materials |
| ACI CODE-318-19(22) |
Building Code Requirements for Structural Concrete (composite slab and concrete fill) |
| IBC 2021 |
International Building Code (Chapter 22 — Steel; Chapter 17 — Special Inspections) |
| FM 4451 |
Approval Standard for Profile Roof Deck |
| FM 4470 |
Approval Standard for Single-Ply, Polymer-Modified Bitumen Sheet, Built-Up Roof (BUR), and Liquid Applied Roof Assemblies for use in Class 1 and Noncombustible Roof Deck Construction |
| UL Fire Resistance Directory |
UL fire-resistance designs for floor-ceiling and roof-ceiling assemblies |
| ASNT SNT-TC-1A |
Personnel Qualification and Certification in Nondestructive Testing (welding inspector qualification, where applicable) |
2.1 Materials, fabrication, and installation shall comply with the latest adopted edition of each standard listed above.
2.2 Where conflicts exist between referenced standards, the more stringent requirement shall govern unless the SER directs otherwise in writing.
3 Submittals
3.1 Action Submittals
3.1.1 The Contractor shall submit the following for review by the SER prior to fabrication and delivery.
☑ Shop drawings — deck layout, fastener pattern, accessories
☐ Mill test reports for base steel
☐ AWS D1.3 welder qualification records
☐ Fastener product data with ICC-ES evaluation reports
☐ Diaphragm design calculations or SDI table reference
☐ Manufacturer product data and load tables
☐ Concrete fill mix design (composite and non-composite floor deck) — coordinate with [[sync/cast-in-place-concrete]]
☐ Fire-rated assembly UL design references (where applicable)
3.1.2 Fabrication shall not begin and material shall not be released for shipment until the corresponding submittals are reviewed and returned.
3.1.3 The Contractor shall allow a minimum of 10 working days for each review cycle.
3.1.4 Shop drawings shall be prepared in accordance with SDI MOC3 and shall show, for each deck area: deck profile and manufacturer's product designation; base steel gauge and design thickness; finish (galvanized coating designation, prime paint, or both); panel layout, including panel length, span direction, side-lap orientation, and end-lap conditions; support fastener type, pattern, and spacing keyed to each support condition; side-lap fastener type and spacing; locations, sizes, and reinforcement details for openings, drains, sumps, and penetrations; accessory locations including pour stops, edge angles, ridge plates, valley plates, closures, cant strips, and column closures; and erection sequence where the sequence affects stability of the partially completed deck.
3.1.5 Mill test reports (MTRs) or certified test reports shall be submitted for each heat or lot of base steel used in the project, confirming compliance with ASTM A653/A653M or ASTM A1008/A1008M as applicable, including yield strength, tensile strength, elongation, and the galvanized coating designation (G60, G90, or as specified).
3.1.6 Material shall not be installed without traceable certification.
3.1.7 Welder and welder operator qualification records shall be submitted in accordance with AWS D1.3/D1.3M for all personnel performing arc spot welds, arc seam welds, and other welded deck attachments.
3.1.8 Welder qualifications shall be current and shall cover the specific deck thickness, welding position, and joint configuration to be performed.
NOTE AWS D1.3 governs sheet steel welding; AWS D1.1 procedures alone are not sufficient for deck-to-support welding because of the thin-gauge sheet involved. (3.1.9)
3.1.10 Fastener product data shall be submitted for all powder-actuated fasteners (PAFs), screws, and other mechanical fasteners used to attach the deck to supports or to fasten side laps.
3.1.11 Fastener product data shall include ICC-ES evaluation reports or equivalent code-compliant evaluation, manufacturer's installation instructions, base-metal thickness ranges for which the fastener is qualified, allowable load tables, and installation tools and settings.
NOTE Each fastener product is qualified for a specific base-metal thickness range; substituting a fastener qualified for a different range is a nonconformance. (3.1.12)
3.1.13 Diaphragm design calculations or the SDI Diaphragm Design table reference used to select the support and side-lap fastener pattern shall be submitted where the contract drawings designate the deck as a diaphragm element.
3.1.14 The diaphragm submittal shall identify the published diaphragm shear capacity used and the deck-and-fastener configuration that achieves it.
3.1.15 Manufacturer's product data sheets shall be submitted for the deck profile, including section properties, allowable loads as a simple, two-span, or three-span condition (per SDI tables), maximum unshored construction span, and load-deflection tables.
3.2 Closeout Submittals
3.2.1 At substantial completion, the Contractor shall provide:
- As-built deck layout shop drawings reflecting any field-approved deviations from the original layout, including locations of field-cut openings and added reinforcement
- Field inspection reports for support fastening, side-lap fastening, and concrete placement (composite slabs), organized by floor or roof area
- Touch-up coating documentation for damaged galvanized surfaces and field-cut edges
- Certificate of compliance from the deck installer attesting that the work was performed in accordance with the contract documents, SDI standards, and AWS D1.3 (welding)
- UL design number documentation for each fire-rated floor-ceiling or roof-ceiling assembly installed, including the deck designation in the UL design and any field-coordination evidence required by the UL design
☑ As-built deck layout shop drawings
☑ Field inspection reports for support and side-lap fastening and concrete placement
☑ Touch-up coating documentation for damaged galvanized surfaces and field-cut edges
☑ Certificate of compliance from the deck installer
☑ UL design number documentation for each fire-rated assembly
4 Quality Assurance
4.1 Installer Qualifications
4.1.1 Steel deck shall be installed by a contractor regularly engaged in the installation of structural steel deck and capable of executing the support and side-lap fastener patterns shown on the shop drawings.
4.1.2 The installer's foreman shall have a minimum of three years of documented experience installing structural steel deck on projects of comparable scope.
4.1.3 Welders performing arc spot welds and arc seam welds for deck attachment shall be qualified under AWS D1.3/D1.3M for the specific deck thickness and welding position.
4.2 Code Compliance and IBC Special Inspection
● Required — per IBC Chapter 17 and Statement of Special Inspections
○ Not required — confirmed in writing by SER and AHJ
4.2.1 Steel deck shall be designed, fabricated, attached, and inspected in accordance with IBC 2021 Chapter 22 and the SDI standards referenced above.
4.2.2 Special inspections of steel deck construction shall be performed in accordance with IBC 2021 Chapter 17 and the project's Statement of Special Inspections (SSI) prepared by the SER.
NOTE Special inspection of deck attachment is required because the structural performance of the deck depends entirely on the quantity, pattern, and quality of the fasteners — the deck panel itself is the smaller part of the engineering decision. (4.2.3)
4.3 Welding Quality
● AWS Certified Welding Inspector (CWI) with documented AWS D1.3 sheet-steel experience
○ AWS CWI plus separate AWS D1.3 inspection authorization
○ Manufacturer-qualified inspector with documented sheet-steel inspection training
4.3.1 Welds attaching deck to supports shall comply with AWS D1.3/D1.3M:2018.
4.3.2 The QA inspector shall be familiar with AWS D1.3 acceptance criteria specifically; an AWS Certified Welding Inspector (CWI) qualified only under AWS D1.1 may not correctly evaluate sheet-steel welds.
NOTE Arc spot welds (puddle welds) and arc seam welds are the deck attachment welds covered by AWS D1.3; they differ from the structural welds covered by AWS D1.1 because the sheet thickness controls weld geometry and acceptance criteria. (4.3.3)
4.4 Manufacturer Qualifications
4.4.1 Steel deck shall be supplied by a manufacturer that is a member of the Steel Deck Institute or that produces deck under a quality management system equivalent to the SDI requirements.
4.4.2 The manufacturer's published section properties, load tables, and diaphragm tables shall be based on testing or calculation methods conforming to AISI S100 and AISI S310; manufacturer load tables not traceable to the AISI specifications shall not be used for design.
5 Environmental and Service Conditions
5.1 Exposure and Atmospheric Conditions
NOTE Steel deck is a thin-gauge cold-formed product, and its service life depends on protecting the base steel from corrosion. (5.1.1)
Concealed interior — covered by ceiling, fireproofing, or finishes; controlled humidity
Exposed interior — visible in conditioned space, low to moderate humidity
Roof deck — typical commercial roofing, single-ply or built-up membrane above
Exposed exterior or high-humidity (parking garage, natatorium, food processing, marine)
● G60 (ASTM A653, 0.60 oz/ft² total both sides) — standard for concealed and typical roof applications
○ G90 (ASTM A653, 0.90 oz/ft² total both sides) — exposed, high-humidity, or aggressive environments
○ A60 (ASTM A653 zinc-iron alloy, 0.60 oz/ft²) — paintable surfaces requiring better paint adhesion
○ Phosphatized and primed — to be field painted; coordinate with paint system
5.1.2 Galvanized coating designation shall be selected based on the service environment of the deck.
5.1.3 G90 (0.90 oz/ft² total both sides) shall be specified for deck exposed to view in parking garages, natatoriums, food and beverage facilities, marine air, or any condition where chloride or moisture exposure is elevated.
5.1.4 Prime paint or phosphatized finishes shall be used only where the deck will be field painted, because the manufacturer's primer is a thin shop coating intended for field-painting compatibility, not a long-term protective coating.
NOTE G60 is the standard finish for concealed locations and typical roof deck under a continuous roofing system and is the most economical and most commonly procured finish; G90 provides 50% more zinc coating at a modest cost premium (typically 5–10%). (5.1.5)
5.2 Construction-Phase Exposure
5.2.1 Steel deck shall be protected from prolonged exposure to standing water, snow accumulation, and aggressive substances during construction.
5.2.2 Deck stored on the ground shall be elevated on dunnage and covered to shed water; bundled deck shall not be stored in direct contact with mud or vegetation.
5.2.3 Water trapped at side laps and end laps can produce white rust (zinc hydroxide bloom) on galvanized surfaces; this is cosmetic in moderate cases but indicates that the zinc is being consumed, and shall be cause for corrective coating in severe cases.
5.3 Fire-Resistance Considerations
○ Not applicable — no fire-resistance rating required for this assembly
● Yes — UL design number indicated on contract drawings
○ Yes — Engineer to designate UL design
5.3.1 Steel deck used in fire-rated floor-ceiling or roof-ceiling assemblies shall be installed in accordance with the specific UL design listed on the contract drawings.
5.3.2 The deck manufacturer's product designation shall match the design as listed.
NOTE Substituting a deck not listed in the referenced UL design voids the fire rating; UL fire-resistance designs specify the deck profile, gauge, finish, concrete topping (where applicable), and any required fireproofing application. (5.3.3)
6 Materials
6.1 Base Steel
● ASTM A653/A653M Structural Steel (SS) Grade 33 minimum — non-composite form deck and roof deck
○ ASTM A653/A653M Structural Steel (SS) Grade 50 — composite floor deck and high-strength applications
○ ASTM A653/A653M Structural Steel (SS) Grade 80 — high-strength roof deck where designed
○ ASTM A1008/A1008M cold-rolled, with separate galvanizing or finishing
NOTE ASTM A653 covers hot-dip galvanized and zinc-iron alloy coated sheet steel and is the standard specification for nearly all steel deck supplied in North America. (6.1.1)
NOTE Structural Steel (SS) Grade 33 (33 ksi minimum yield) is the default for roof deck and non-composite form deck profiles in the most common gauges. (6.1.2)
NOTE Composite floor deck profiles typically use Grade 50 (50 ksi minimum yield) to achieve the section capacity needed for the composite-slab span and load tables. (6.1.3)
6.1.4 Grade 80 may be used for roof deck where higher strength reduces required gauge, but the section properties of the cold-formed profile, not the base material strength alone, control the design.
NOTE ASTM A1008 cold-rolled sheet without integral galvanizing is used only where the deck will receive a separately applied finish; nearly all commercial deck production uses A653 because it incorporates galvanizing in the same continuous process. (6.1.5)
6.2 Deck Profile
NOTE Steel deck is classified by its function and its profile geometry. (6.2.1)
Composite floor deck (acts compositely with concrete topping)
Non-composite form deck (concrete slab carries gravity load; deck is permanent form)
Roof deck (Type B, Type N, Type A, or Type F)
Combination — composite floor deck and roof deck on same project
Per drawings
Not applicable — floor deck only
Type A — narrow-rib, 1-1/2 in. depth (legacy profile, limited current production)
Type F — intermediate-rib, 1-1/2 in. depth (legacy profile, limited current production)
Type B — wide-rib, 1-1/2 in. depth (industry standard for typical commercial roofing)
Type N — deep-rib, 3 in. depth (long-span roof deck)
Deep deck — 4-1/2 in. to 7-1/2 in. depth (very long span or low-slope long-span roofs)
Per drawings
Not applicable — non-composite or roof deck
1-1/2 in. composite deck (light-duty composite slab, short spans)
2 in. composite deck (most common — typical office and commercial spans)
3 in. composite deck (longer spans or heavier loads)
Per drawings
Not applicable — composite or roof deck
9/16 in. form deck (very short spans, light slabs)
1 in. form deck (typical non-composite floor slabs)
1-1/2 in. form deck (longer spans or heavier slabs)
Per drawings
6.2.2 The structural drawings shall identify the deck function (composite, non-composite, or roof) and either the SDI profile classification or the manufacturer's product designation.
6.2.3 The Contractor shall not substitute a different profile, even from the same manufacturer, without written approval of the SER, because section properties and load tables differ.
6.2.4 Type A and Type F narrow- and intermediate-rib profiles have largely been displaced by Type B in current production and should not be specified for new construction unless a specific reason exists.
NOTE Type B (1-1/2 in. wide-rib) is the dominant roof deck profile in current commercial construction, pairs well with rigid insulation board over single-ply and built-up membrane roofing, and is universally available; Type N (3 in. deep-rib) is specified for longer spans (typically 12 ft to 18 ft), and deep deck profiles (4-1/2 in. to 7-1/2 in.) for very long spans (20 ft to 35 ft or more) in warehouses, distribution centers, and large arenas. (6.2.5)
NOTE Composite floor deck is supplied in three predominant depths: 2 in. (most common, spanning typical 8 ft to 12 ft bays with a finished slab thickness of 4-1/2 in. to 6-1/2 in.), 1-1/2 in. (shorter spans, lower loads, or constrained floor depth), and 3 in. (longer spans of 12 ft to 16 ft and heavier loads, reducing concrete fill volume). (6.2.6)
6.3 Gauge and Design Thickness
NOTE Steel deck gauge is identified by gauge number (16, 18, 20, 22) where lower gauge numbers indicate thicker steel. (6.3.1)
NOTE Each gauge corresponds to a design thickness used in cold-formed steel calculations per AISI S100; the design thickness is approximately 95% of the minimum delivered base-steel thickness, reflecting the AISI convention that excludes coatings from the structural calculation. (6.3.2)
22 gauge (0.0295 in. design thickness, light-duty roof deck only)
20 gauge (0.0358 in. design thickness, common roof and form deck)
18 gauge (0.0474 in. design thickness, typical composite and heavy roof deck)
16 gauge (0.0598 in. design thickness, heavy composite or long-span deck)
Per drawings
6.3.3 The Contractor shall not substitute a lighter gauge than specified, because gauge directly controls section capacity, diaphragm capacity, and fastener pull-out resistance.
NOTE 22 gauge is the lightest gauge in common production (short-span roof deck under light loads, rarely specified except for re-roof matching); 20 gauge is standard for typical Type B roof deck and non-composite form deck; 18 gauge is standard for composite floor deck and heavier roof loads; 16 gauge is specified for composite deck at longer spans (12 ft or greater), heavy floor loads, or high-diaphragm-capacity roof deck. (6.3.4)
6.4 Deck Length and End-Lap Conditions
● Lapped at supports per SDI MOC3 (minimum 2 in. end lap, attached at support)
○ Butted at supports with attachment to support per SDI MOC3
6.4.1 Deck panels shall be furnished in lengths that minimize the number of end laps and maximize the use of the deck's continuous-span capacity.
6.4.2 The Contractor shall lay out panels per the shop drawings to achieve continuous-span behavior wherever the structural design relies on it.
NOTE SDI tables present allowable loads for single-span, two-span continuous, and three-span continuous conditions; three-span and two-span continuous conditions produce significantly higher capacity than single-span because of moment redistribution at the interior supports. (6.4.3)
6.4.4 End laps shall occur at a support and shall not be floated between supports.
6.4.5 Lapped end joints are the standard SDI detail for roof deck and non-composite form deck and shall have a minimum lap of 2 in. with the lap attached to the support through both layers.
6.4.6 Butted end joints are common for composite floor deck where end-lap leakage of fresh concrete would be problematic; butted joints shall have attachment to the support of both panels and shall be backed by a butt strip where required by the manufacturer or by the contract drawings.
7 Attachment to Supports
NOTE The attachment of steel deck to its supporting structure is the most consequential decision in deck specification, because it controls gravity load capacity (resistance to uplift, side-bending, and panel buckling), diaphragm shear capacity, and panel stability under construction loads. (7.1)
7.2 The structural drawings shall specify the support fastener type, the fastener pattern (number of fasteners per panel width at each support), and the spacing of fasteners along supports.
7.3 Support Fastener Type
Arc spot welds (puddle welds) per AWS D1.3 — most common for floor deck and heavy roof deck
Arc seam welds per AWS D1.3 — used where greater shear capacity per fastener is needed
Powder-actuated fasteners (PAFs) — common for roof deck and non-composite form deck
Self-drilling, self-tapping screws — light loads, retrofit, or where welding/PAFs are restricted
Per drawings
7.3.1 The Contractor shall verify that the proposed PAF is qualified for the gauge of the supporting steel; typical PAFs require a minimum support thickness of 1/8 in. or 3/16 in. flange, and thinner supports require a different fastener type or welding.
NOTE Arc spot welds (puddle welds) made through the deck are the historical standard and remain common for composite floor deck and heavy roof deck; each develops substantial shear and pull-out capacity that can be tuned to match diaphragm demand, but they require qualified welders, calibrated equipment, weld washers for thinner deck (22 gauge and sometimes 20 gauge) to prevent burn-through, and the deck in firm contact with the support and free of paint or galvanized buildup at the weld location. (7.3.2)
NOTE Powder-actuated fasteners (PAFs) — pins driven through the deck into the support flange by a powder-charge tool — have largely displaced welds for roof deck attachment because they are faster, require no certified welders, and introduce no localized heat into the galvanized coating; PAF capacity is governed by ICC-ES evaluation reports for each specific fastener and supporting-steel thickness combination. (7.3.3)
NOTE Self-drilling, self-tapping screws are used where welding and PAFs are restricted (hospitals, schools, or operating facilities where weld spatter or PAF noise is unacceptable) and for attaching deck to thin secondary supports such as cold-formed steel framing; screws have lower per-fastener shear capacity than welds and most PAFs and are typically required in higher quantities, while combination patterns suit support members of differing thicknesses. (7.3.4)
7.4 Support Fastener Pattern
NOTE SDI uses a "X/Y" notation to describe the support fastener pattern, where X is the number of fasteners across the panel width at the support and Y is the panel width in flute units. (7.4.1)
NOTE For example, "36/4" means four fasteners across a 36 in. wide panel at each support (one fastener per 9 in. of panel width). "36/7" means seven fasteners across a 36 in. wide panel at each support (one fastener per ~5 in. of panel width, achieved by placing a fastener in each rib valley plus additional fasteners in the flat). (7.4.2)
NOTE Heavier patterns produce higher diaphragm capacity but require more fasteners and more labor. (7.4.3)
36/4 — every third valley (light pattern, typical roof deck)
36/5 — every other valley (moderate pattern)
36/7 — every valley (typical heavy roof deck or composite floor deck)
36/9 — every valley plus intermediate (high diaphragm capacity)
Per drawings
7.4.5 Deck designed as a diaphragm element shall use the pattern specified on the drawings without substitution, because the diaphragm shear capacity is computed from the specific pattern and fastener type.
NOTE Substituting a lighter pattern or a different fastener type reduces diaphragm capacity and is a nonconformance. (7.4.6)
7.5 Arc Spot Weld Requirements
5/8 in. visible diameter — minimum per AWS D1.3 for typical deck
3/4 in. visible diameter — heavy patterns and thicker deck
Per AWS D1.3 Table 5.4 based on deck thickness
● Not required — deck design thickness ≥ 0.028 in.
○ Required for deck thinner than 22 gauge or where specified by manufacturer
7.5.1 Arc spot welds shall be made in accordance with AWS D1.3/D1.3M:2018.
7.5.2 The minimum arc spot weld visible-diameter shall be 5/8 in. for deck up to 0.06 in. design thickness, increasing per AWS D1.3 for thicker deck.
7.5.3 Welds shall be made in firm contact with the supporting steel; the deck shall not be bridged or warped at the weld location.
7.5.4 Where deck is thinner than 22 gauge (0.028 in.) the welder shall use a weld washer (a flat steel washer placed on top of the deck through which the weld is made) to prevent burn-through; weld washers shall conform to the deck manufacturer's specification.
7.5.5 Welds shall be visually inspected after cooling for full perimeter fusion, absence of porosity at the visible surface, no burn-through, and no cracks.
7.5.6 The weld shall completely fuse the deck to the support; welds that show only surface adherence (a "lollipop" with no fusion) shall be rejected and remade.
7.5.7 The visible diameter on the top of the deck shall be measured; welds smaller than the minimum specified diameter shall be remade or supplemented with an additional weld immediately adjacent.
7.6 Powder-Actuated Fastener Requirements
☑ Verify fastener model is listed for support thickness in ICC-ES report
☐ Verify operator certification card current
☐ Visual inspection of installed fastener for flush seating
☐ Random pull-out testing per manufacturer recommendation
7.6.1 Powder-actuated fasteners shall be installed in accordance with the manufacturer's instructions and within the range of supporting steel thicknesses covered by the fastener's ICC-ES evaluation report.
7.6.2 The Contractor shall verify the actual flange thickness of the supporting steel before installation; PAFs driven into supports thinner than the qualified range are not properly anchored and shall be supplemented or replaced.
7.6.3 The tool operator shall be trained by the fastener manufacturer or distributor and shall hold a current operator's card or certification card.
7.6.4 Powder charges shall be selected to drive the fastener fully without overdriving (overdriving creates a depression and reduces shear capacity by deforming the deck and reducing the effective contact area) and without underdriving (underdriving leaves a gap between fastener head and deck and reduces shear capacity).
7.6.5 The installed fastener head should be flush with the deck surface or recessed not more than 1/16 in.
7.7 Self-Drilling Screw Requirements
Not applicable — screw attachment not used
#12 self-drilling screw with hex washer head — typical light-duty attachment
#14 self-drilling screw with hex washer head — typical structural attachment
1/4 in. self-drilling screw with hex washer head — heavy patterns
7.7.1 Where deck is attached with self-drilling, self-tapping screws, the screw shall be a structural-grade screw listed for steel-to-steel attachment with adequate point and thread design for the supporting steel thickness.
7.7.2 Screws shall be installed perpendicular to the deck and shall be driven until the head is firmly seated against the deck without overtorquing (which strips the threads and dramatically reduces pull-out capacity).
7.7.3 Screw guns shall be set with depth control or torque control to prevent overdriving.
8 Side-Lap Fastening
NOTE Side-lap fasteners connect adjacent deck panels along their longitudinal edges, between supports. (8.1)
NOTE Side-lap fastening is structurally important for diaphragm action because it forces adjacent panels to act as a continuous diaphragm rather than as independent strips; without adequate side-lap fastening, the panels can slip relative to each other under diaphragm shear and the diaphragm capacity drops dramatically. (8.2)
NOTE Side-lap fastening is also important for keeping wet concrete from leaking through side-lap gaps during composite-slab placement. (8.3)
8.4 Side-Lap Fastener Type
Button punch (mechanical interlock) — common for non-composite form deck and light roof deck
Self-drilling, self-tapping screws (#10 or #12) — typical for diaphragm-rated deck
Arc seam welds per AWS D1.3 — high-shear diaphragm applications
Pneumatic-driven pins — proprietary, manufacturer-specified
No side-lap fastener — short spans, low diaphragm demand only
Per drawings
NOTE Button-punch side-lap fasteners are formed in the field by a tool that crimps the upper and lower sides of the lap together into a mechanical interlock; they have moderate shear capacity and are used on roof deck and form deck where diaphragm demand is light. (8.4.1)
NOTE Screws (typically #10 or #12 self-drilling, self-tapping) are the most common side-lap fastener for diaphragm-rated deck because their capacity is established in the SDI diaphragm tables and is reproducible and inspectable in the field. (8.4.2)
NOTE Arc seam welds along the side lap are used for the highest-shear-demand diaphragms (large multi-story buildings in high seismic zones) but require more skilled labor and produce more localized heat in the galvanized coating. (8.4.3)
NOTE Pneumatic-driven pins (proprietary fastener systems) are used by some installers under their own manufacturer's published diaphragm tables. (8.4.4)
8.5 Side-Lap Fastener Spacing
No side-lap fastener (button-punch optional)
36 in. (one fastener at mid-span only)
24 in.
18 in.
12 in.
Per SDI diaphragm table — varies by zone
Per drawings
8.5.2 Tighter side-lap spacing shall be provided at locations of high diaphragm demand — around large openings, at exterior walls in seismic zones, and where the deck transfers significant lateral load to the lateral force-resisting system — because tighter spacing increases diaphragm shear capacity.
8.5.3 The Contractor shall not space side-lap fasteners further apart than specified, even where the spacing appears redundant.
8.6 Side-Lap Installation
8.6.1 The lap shall be fully engaged before the fastener is installed; the upper lip shall be seated firmly against the lower lip with no visible gap.
8.6.2 Where the lap has been crushed, twisted, or deformed during handling or installation traffic, the deformation shall be corrected before fastening or the affected panel shall be replaced.
8.6.3 Screws installed at side laps shall pass through both deck plies fully and shall not be installed through only one ply or through one ply with the second ply pushed aside.
9 Composite Slabs (Composite Floor Deck)
NOTE Where the deck acts compositely with a concrete topping to form the structural floor slab, the requirements of SDI C-2017 and ANSI/AISC 360-22 Chapter I apply. (9.1)
NOTE The composite action depends on the embossment pattern in the deck flutes engaging the concrete, the bond between deck and concrete, and the integrity of the slab as a flexural element. (9.2)
9.3 Concrete Topping
Not applicable — non-composite or roof deck
3,000 psi
3,500 psi
4,000 psi
5,000 psi
Per drawings
Not applicable — non-composite or roof deck
4-1/2 in. (2 in. deck + 2-1/2 in. topping) — typical office and commercial
5 in. (2 in. deck + 3 in. topping) — fire-rated or heavier loads
5-1/2 in. (2 in. deck + 3-1/2 in. topping)
6-1/2 in. (3 in. deck + 3-1/2 in. topping) — longer spans
Per drawings
● Normal-weight concrete (145 to 150 pcf)
○ Lightweight concrete (110 to 115 pcf) — reduces dead load, may extend span
9.3.2 The structural drawings shall specify the concrete compressive strength, slump or slump flow range, normal-weight or lightweight aggregate, and total slab thickness (deck depth plus topping thickness above the top of the deck).
NOTE Typical composite slabs use 3,000 psi to 5,000 psi concrete with a total slab thickness of 4-1/2 in. to 6-1/2 in. (9.3.3)
9.4 Construction Loads and Unshored Spans
● Unshored construction — deck supports wet concrete and construction loads alone
○ Shored construction — temporary supports installed prior to concrete placement
Per drawings
9.4.1 Composite floor deck shall be installed and concreted as either an unshored or shored construction.
9.4.2 The Contractor shall verify the unshored span capacity from the manufacturer's published tables for the specific deck profile, gauge, and span condition (single, two-span, or three-span).
9.4.3 Where the support spacing on the drawings exceeds the published unshored span, shoring shall be installed prior to concrete placement.
NOTE In unshored construction the deck alone must carry the wet concrete plus minimum construction live loads (typically 20 psf per SDI C-2017) without exceeding allowable bending stress or deflection limits, whereas shored construction places temporary supports during concreting (removed after cure) and is required where the span exceeds the unshored capacity. (9.4.4)
9.5 Composite Slab Reinforcement
Welded wire reinforcement only (typical 6×6 W2.9×W2.9 or 6×6 W4.0×W4.0)
WWR plus negative-moment rebar over interior supports
Deformed bars throughout — no WWR
Per drawings
NOTE Composite slabs require reinforcement above the deck for shrinkage and temperature control, for negative-moment resistance over interior supports, and for distribution of concentrated loads; welded wire reinforcement (WWR) is the most common, supplemented with deformed bars at supports and around openings. (9.5.2)
9.6 Concrete Placement on Deck
9.6.1 Concrete shall be placed without overloading the deck.
9.6.2 Concrete buggies, pumps, and discharge hoses shall not concentrate load at a single panel that exceeds the deck's construction-load capacity.
9.6.3 Pour direction shall progress from one support toward the next; concrete shall not be discharged in piles that exceed the slab thickness, because the resulting weight concentrates load between supports.
9.6.4 Vibrating the concrete shall be performed to consolidate the concrete and engage the embossments in the deck flutes; the embossments are the mechanical key for composite action.
9.6.5 However, internal vibrators shall not be used in contact with the deck face, because contact can damage the galvanized coating and is not effective at consolidating the deck-concrete interface.
9.6.6 Vibrators shall be inserted vertically into the slab and shall consolidate the slab thickness as a whole.
10 Roof Deck
NOTE Where the deck is used as a roof deck, the deck supports the weight of the roofing system, insulation, mechanical equipment supports (curbs and rails), and live loads (snow, rain, and live load per ASCE 7-22), and resists wind uplift from the roofing membrane and parapet conditions. (10.1)
10.2 Roof deck shall be installed in accordance with SDI RD-2017 and with the manufacturer's roof-deck product data.
10.3 Insulation and Roofing Coordination
NOTE Roof deck is the structural substrate for the roofing assembly but is not the roofing system itself. (10.3.1)
● G60 or G90 galvanized only — to receive insulation board above
○ Galvanized with shop primer for paint compatibility
10.3.2 The roof insulation, cover board, membrane, fasteners, and flashings are governed by the roofing specifications and shall be coordinated with the deck profile and the deck's ability to receive roofing fasteners.
NOTE Single-ply membrane systems require an insulation or cover board substrate over the deck flutes; the deck flutes themselves are not a usable substrate for membrane bonding. (10.3.3)
10.4 Wind Uplift
○ Single uniform fastener pattern across entire roof
● Zoned per ASCE 7-22 (corner, edge, field) — patterns shown on drawings
Per drawings
10.4.1 Roof deck shall be attached to resist the design uplift pressures derived from ASCE 7-22 wind loading.
10.4.2 The Contractor shall execute the zoned pattern shown without substitution.
NOTE Uplift is resisted by the support fastener system (fastener pull-out from the supporting steel and pull-over of the deck around the fastener head); wind uplift is highest at the roof corners and edges, so the contract drawings typically show zoned patterns with denser fastening at corners and edges and lighter fastening in the field. (10.4.3)
10.5 FM Approval
● Not required — code-compliant design only
○ FM 4470 Class 1 roof assembly required
○ FM 4470 Class 1 plus specific windstorm rating (1-60, 1-90, 1-120, etc.)
10.5.1 Where the project specifies FM Global insurance compliance, the roof deck and roof assembly shall be tested and approved per FM 4451 (Profile Roof Deck) and the roof assembly shall be approved per FM 4470 (Single-Ply, Modified Bitumen, and BUR systems on noncombustible deck).
10.5.2 Where FM approval requirements and the structural-only design both apply, the more stringent shall govern, because FM approval imposes specific deck-to-support attachment requirements that may exceed the structural-only design.
11 Diaphragm Action
NOTE A horizontal diaphragm is the floor or roof element that collects lateral loads (wind and seismic) and transfers them to the vertical lateral force-resisting system (shear walls, braced frames, or moment frames). (11.1)
NOTE Steel deck acts as a diaphragm by virtue of its in-plane shear stiffness and strength; the diaphragm capacity depends on the deck profile, deck gauge, support fastener type and pattern, side-lap fastener type and spacing, and the span of the diaphragm between vertical elements. (11.2)
11.3 Diaphragm Design Source
● SDI Diaphragm Design Manual (DDM04) tables — most common
○ AISI S310 design calculations — engineered diaphragm
○ Manufacturer's proprietary diaphragm test data and tables
○ Not applicable — deck is not relied upon for diaphragm action
NOTE The SDI DDM04 diaphragm tables provide allowable diaphragm shear capacity for combinations of deck profile, deck gauge, support fastener type and pattern, and side-lap fastener type and spacing. (11.3.1)
11.3.2 The SER selects the table entry that meets or exceeds the demand and the deck shall be installed with the exact configuration listed.
11.3.3 AISI S310 provides the analytical method underlying the SDI tables and may be used for configurations outside the tabulated range.
11.3.4 Manufacturer proprietary tables (typically based on full-scale cantilever diaphragm tests) may be used where the proprietary fastener system is specified.
11.4 Diaphragm Special Inspection
☑ Deck profile and depth match drawings
☐ Deck gauge match drawings (mill marking or microcalliper measurement)
☐ Support fastener type and pattern match drawings
☐ Side-lap fastener type and spacing match drawings
☐ Deck attachment to perimeter shear collectors verified
11.4.1 Where the deck is relied upon for diaphragm action, the IBC special inspector shall verify that the actual installed deck profile, gauge, support fastener type and pattern, and side-lap fastener type and spacing match the configuration on the drawings exactly.
NOTE A substitution that appears equivalent on inspection (for example, screws of one size for screws of a different size) may produce a different diaphragm capacity and is a nonconformance. (11.4.2)
12 Openings, Penetrations, and Reinforcement
12.1 Small Openings
6 in. in any dimension
8 in. in any dimension
12 in. in any dimension
Per Engineer of Record
12.1.1 Small penetrations through the deck (single small ducts, pipes, conduits, smaller than approximately 8 in. in any dimension) may be cut in the field by the trades requiring the penetration, but shall be cut cleanly using a metal hole saw or other clean-cut method; torch cutting is not permitted because it damages the galvanized coating and produces a notch geometry that initiates cracking.
12.1.2 Cut edges shall be touched up with a zinc-rich coating to restore corrosion protection.
12.2 Larger Openings
12.2.1 Openings larger than the field-cut threshold above shall be detailed on the contract drawings or designed by the SER and shall be reinforced with structural framing — typically L-shaped or channel-shaped angle frames welded or bolted to the deck supports and to the deck — to transfer the deck loads around the opening.
12.2.2 The Contractor shall not cut large openings in the field without written direction from the SER.
12.2.3 Reinforcement for large openings shall be coordinated with Structural Steel Framing where the reinforcement attaches to the primary steel. 12.3 Sumps and Drains
12.3.1 Roof deck areas at drains, scuppers, and sump locations shall be installed with the deck profile sloped or with manufactured sump pans set into the deck per the contract drawings.
12.3.2 Sump pans shall be of the same gauge and finish as the deck and shall be welded or fastened to the surrounding deck and supports to maintain diaphragm continuity.
13 Accessories
☑ Pour stops at slab edges (composite and non-composite floor deck)
☐ Edge angles at deck terminations
☐ Ridge plates at roof ridges
☐ Valley plates at roof valleys
☐ Cant strips at parapet and curb transitions
☐ Column closures at column penetrations
☐ Cell closures at deck ends (open-rib roof deck above heated space)
☐ Sump pans at roof drains and floor drains
13.1 Steel deck installations require numerous accessory components, all of which shall be furnished by the deck manufacturer or by an approved supplier and shall match the deck finish and gauge unless otherwise specified.
13.2 Pour Stops
NOTE Pour stops are vertical plates installed at the edge of a composite or non-composite slab to retain the wet concrete during placement. (13.2.1)
13.2.2 Pour stops shall be sized to extend from the top of the deck to the top of the concrete slab and shall be attached to the deck and to the perimeter steel framing per the contract details.
13.2.3 The pour-stop gauge shall be heavier than the deck gauge to resist concrete pressure without bowing; 16 gauge or 14 gauge is typical even where the deck itself is 18 gauge or 20 gauge.
13.3 Roof-Deck Accessories
NOTE Ridge and valley plates, cant strips, and closures are roof-deck accessories used at geometry transitions and at the perimeter of the roof. (13.3.1)
NOTE Cell closures (sometimes called rib closures or vent closures) are installed in the open ribs of roof deck at the deck ends or at deck terminations to prevent the open ribs from acting as paths for unconditioned air infiltration into the building; they are particularly important where roof deck extends over heated, conditioned space. (13.3.2)
14 Installation
14.1 Storage and Handling
14.1.1 Deck shall be delivered to the project site in bundles labeled with the manufacturer's product designation, gauge, finish, and quantity.
14.1.2 Bundles shall be stored on dunnage above grade, protected from standing water, and covered to shed precipitation.
14.1.3 Bundles shall not be stacked higher than the manufacturer's published maximum stack height, because excess stack height can produce permanent set in the lower panels.
14.1.4 Deck bundles shall not be stored directly on the partially erected structural steel where their concentrated weight could overload an erector's bay; the deck contractor shall coordinate with the erector for staging locations.
14.2 Erection Sequence
14.2.1 Deck shall be erected in accordance with the approved erection sequence and the SDI MOC3.
14.2.2 Deck shall not be placed onto a portion of the structural steel that has not been bolted and welded in accordance with the contract documents; deck shall not be relied upon to brace the structural steel during erection unless the structural steel design specifically permits it.
14.2.3 The deck installation shall follow behind the structural steel erection by an appropriate interval.
14.2.5 Final attachment (per the support and side-lap fastener pattern) shall be completed before any concentrated load is applied to the deck.
14.3 Construction Loads on Deck
14.3.1 Construction loads (material storage, scaffolding bases, equipment) shall not be concentrated on the deck at locations where the load exceeds the deck's published unshored construction load capacity.
14.3.2 Material pallets, conduit reels, and equipment bases shall be distributed across multiple panels and shall be placed near supports rather than at mid-span.
14.3.3 Concentrated wheel loads (such as small equipment carts or buggies) shall be coordinated with the deck manufacturer's published wheel-load tables.
14.4 Field Cutting and Notching
● Zinc-rich cold galvanizing compound — match galvanized finish
○ Organic zinc-rich primer
○ Manufacturer-recommended touch-up coating
14.4.1 Field cutting of the deck shall be done with a hole saw, jigsaw with metal-cutting blade, shears, nibblers, or other clean-cut method.
14.4.2 Plasma torches and oxyacetylene torches shall not be used to cut deck because they destroy the galvanized coating at the cut edge and produce ragged edges that initiate cracking.
14.4.3 Cut edges and any field-damaged galvanized surfaces shall be touched up with a zinc-rich coating (organic or inorganic zinc primer) within 24 hours of exposure.
14.5 Coordination with Fireproofing
NOTE See
Fireproofing for fireproofing requirements, bond strength testing, and patch and repair after deck cutting.
(14.5.1) 14.5.2 Where spray-applied fireproofing is to be applied to the underside of the deck — typically for composite floor deck in a fire-rated assembly — the deck galvanized finish shall be compatible with the fireproofing bond requirements.
14.5.3 The Contractor shall verify fireproofing compatibility against the specific UL design listed; most spray-applied cementitious fireproofing is qualified for application directly to G60 galvanized deck.
14.5.4 Where prime paint or other shop coatings are applied to the deck, the fireproofing manufacturer shall confirm bond compatibility prior to application.
14.6 Coordination with Reinforcement Placement
14.6.2 Bar chairs shall be selected for compatibility with the deck profile; chair feet shall bear on the deck flat top surface (not on the open rib) wherever possible to prevent the chair from puncturing or distorting the deck.
15 Field Inspection
15.1 Pre-Pour Inspection (Composite and Non-Composite Floor Deck)
● Contractor checklist plus Special Inspector observation report
○ Special Inspector observation report only
○ Contractor checklist only (where no special inspection required)
15.1.1 Before concrete is placed on any deck area, the Contractor shall perform and document an inspection confirming: deck profile and gauge match the shop drawings; support fastener type and pattern match the drawings (visual count and weld/PAF/screw inspection); side-lap fastener type and spacing match the drawings; deck panel laps and end-lap details are correct; pour stops, edge angles, and closures are installed; openings and penetrations are reinforced where required; field-cut edges and damaged areas are touched up.
15.1.2 For composite slabs, the inspection shall additionally confirm that the deck embossments are clean and free of mud, ice, or coatings that would prevent composite action.
15.2 Weld Inspection
100% visual inspection (typical for diaphragm-rated deck)
Representative sample inspection per Statement of Special Inspections
Per Statement of Special Inspections
15.2.1 Where the deck is attached by arc spot welds or arc seam welds, the QA inspector shall visually inspect a representative sample of welds at each support condition for visible diameter, fusion, absence of cracks, absence of burn-through, and absence of porosity at the visible surface.
15.2.2 The weld inspection rate shall be as required by the project SSI; typical practice is 100% visual inspection of welded attachments because the deck-to-support weld is structurally critical and the inspection is rapid.
15.3 Fastener Inspection (PAF and Screw)
15.3.1 Powder-actuated fasteners and screws shall be inspected for proper seating (head flush or slightly recessed, no overdrive or underdrive), correct quantity at each support, and conformance with the specified pattern.
15.3.2 Visual inspection alone is normally adequate; where doubt exists, random pull-out testing per the manufacturer's procedure may be performed.
15.4 Concrete Placement Observation (Composite Slabs)
15.4.1 During concrete placement on composite floor deck, a qualified individual shall monitor the deck for deflection, lap separation, and any sign of overload.
15.4.2 If excessive deflection is observed, placement shall be stopped at the location of concern, the deck condition shall be evaluated, and placement shall not resume until the cause is identified and corrected (typically by adding shoring or by re-distributing the concrete buggy traffic).
Per drawings — project schedule
15.5.1 Any deck installation that does not conform to the contract documents, the approved shop drawings, or the requirements of the SDI standards shall be documented as a nonconformance by the Special Inspector and reported to the SER, the Contractor, and the Owner in writing before subsequent work proceeds.
15.5.2 For composite floor deck, concrete shall not be placed over a documented nonconformance until the SER has issued a written disposition.
15.5.3 For roof deck, the roofing system shall not be installed over a documented nonconformance.
16 Delivery, Storage, and Handling
16.1 Steel deck shall be delivered to the project site in clearly labeled bundles identified by deck product designation, profile, gauge, finish (G60 or G90), and quantity.
16.2 Bundles shall carry certification tags traceable to the mill test reports submitted under the Action Submittals section.
16.3 Material shall not be accepted without traceable certification.
16.4 Bundles shall be stored above grade on timber or other dunnage, protected from standing water, and covered with weatherproof tarps that allow air circulation.
16.5 Bundles shall not be stored in direct contact with mud, vegetation, or chemicals that could accelerate corrosion of the galvanized coating.
16.6 Where deck is stored on the partially erected structural steel for ease of placement, the storage location shall be coordinated with the steel erector to avoid overloading any single bay.
16.7 Deck shall be handled with nylon slings, padded chokers, or other methods that do not score, dent, or damage the galvanized coating.
16.8 Wire rope slings shall not be used directly on galvanized deck.
16.9 Bundles dropped from height or stacked improperly may develop permanent set in the lower panels; such panels shall be inspected and rejected if their profile deviates from the specified geometry.
16.10 Galvanized deck stored for prolonged periods in damp or poorly ventilated conditions may develop white rust (zinc hydroxide), which is a cosmetic and minor structural concern that indicates the zinc coating is being consumed.
16.11 Light white rust may be wiped off and the surface allowed to dry before installation; heavy white rust requires the panels to be cleaned and the coating restored, or the panels rejected.
17 Warranty
1 year from substantial completion
2 years from substantial completion
17.1 The Contractor shall warrant the steel deck installation against defects in workmanship — including incorrect deck profile, gauge, or finish; incorrect or missing support fasteners; incorrect or missing side-lap fasteners; damaged galvanized coating not touched up; and any deviation from the approved shop drawings — for the project warranty period.
17.2 Material warranties provided by the deck manufacturer shall be passed through to the Owner.
17.3 Where the deck is part of a fire-rated assembly, the Contractor shall additionally warrant that the deck-and-coating-and-fireproofing combination matches the UL design listed on the contract drawings; deviation from the listed design voids the fire rating and constitutes a warranty defect.
17.4 The Contractor's warranty shall not limit the SER's right to require corrective work for nonconforming conditions discovered during the warranty period, including conditions concealed by subsequent work that are exposed during routine maintenance or alteration.