Gravel stops and metal fascia at low-slope roof edges are among the most wind-vulnerable elements of a commercial building. When the edge metal fails in a windstorm, the roof membrane frequently follows — a progressive failure that transforms a manageable wind event into a major loss. ANSI/SPRI ES-1, the Wind Design Standard for Edge Systems, exists precisely to prevent that failure mode. Architects specifying roof edge metal on commercial projects must understand ES-1, when it applies, and how to write a specification that enforces it without creating substitution gaps that contractors exploit.
What Is a Gravel Stop vs. a Fascia?
These terms are often used interchangeably but describe different profiles:
| Profile Type | Primary Function | Typical Use |
|---|---|---|
| Gravel Stop | Retains aggregate surfacing; provides finished roof edge | Built-up roofs with gravel ballast; low fascia heights (2–4 inches) |
| Metal Fascia | Conceals the roof edge substrate; provides architectural finish | Membrane roofs without aggregate; taller fascia heights (4–12+ inches) |
| Combination Fascia | ES-1-tested system with integrated cleat and face panel | Higher wind zones; FM Global insured projects |
| Drip Edge | Directs water off sloped roof into gutter | Steep-slope; not a low-slope edge metal application |
Both gravel stops and fascia are specified under CSI 07 71 00 (Roof Specialties) when they are proprietary engineered systems, and under 07 62 00 when custom-fabricated. ES-1 testing is only meaningful when the system installed exactly matches the tested assembly — gauge, fastener size, spacing, and substrate type.
ANSI/SPRI ES-1 Wind Design Standard
ANSI/SPRI ES-1 was developed by the Single Ply Roofing Industry to address the catastrophic roof edge failures documented in post-storm investigations following Hurricane Andrew (1992) and subsequent events. The standard establishes:
- ES-1 Test Method RE-1: Static resistance of the edge system to uplift forces applied at the top of the fascia
- ES-1 Test Method RE-2: Resistance of the nailer/cleat attachment to the substrate
- ES-1 Test Method RE-3: Dynamic fatigue testing simulating repeated wind loading cycles
A passing ES-1 system earns a rated design pressure (in pounds per square foot) that must be compared to the design wind pressure calculated for the roof edge under ASCE 7. The designer — not the contractor — is responsible for ensuring the rated capacity of the specified ES-1 system meets or exceeds the calculated design pressure.
FM Global requirement: Projects with FM Global property insurance are typically required to use ES-1-tested edge metal, or to have edge metal tested to FM 1-49. FM approval documents list specific tested assemblies. When a project is FM insured, the spec should require FM-approved edge systems and include FM 1-49 in the reference standards.
Gauge Requirements for Gravel Stops and Fascia
Minimum gauges for gravel stops and fascia are governed by SMACNA and modified by ES-1 test data for proprietary systems:
| Application | Minimum Steel | Minimum Aluminum | Notes |
|---|---|---|---|
| Gravel stop, fascia ≤ 4" high | 24 ga (0.0239") | .040" (1.0 mm) | SMACNA minimum |
| Fascia 4"–8" high | 22 ga (0.0299") | .050" (1.27 mm) | Increased stiffness required |
| Fascia 8"–12" high | 20 ga (0.0359") | .063" (1.6 mm) | Structural nailer required |
| ES-1-tested proprietary system | Per test report | Per test report | Cannot substitute lighter gauge |
Nailer and Cleat Requirements
The edge metal nailer or continuous cleat is the structural connection between the edge metal and the building. Nailer sizing is not interchangeable — an ES-1-tested system tied to a specific nailer gauge, fastener pattern, and substrate type cannot be substituted in the field without invalidating the wind rating. Spec language must require:
- Nailer material (pressure-treated wood, composite, or metal) and dimensions matching the test report
- Fastener type, size, and spacing as tested (e.g., "#14 wood screws at 12 inches o.c. into minimum 2x blocking")
- Substrate thickness and species (for wood nailers) or gauge (for metal nailers) as tested
- Prohibition on field modification of fastener spacing or substitution of nailer material without re-testing
Specification Language for Division 07 71 00 Roof Edge Metal
The following represents representative spec language for an ES-1-tested gravel stop and fascia system:
PART 1 — GENERAL
1.1 REFERENCES
A. ANSI/SPRI ES-1: Wind Design Standard for Edge Systems Used with Low Slope Roofing Systems.
B. FM Global: Loss Prevention Data Sheet 1-49 (Perimeter Flashing).
C. SMACNA: Architectural Sheet Metal Manual, 7th Edition.
PART 2 — PRODUCTS
2.1 ROOF EDGE METAL — GRAVEL STOP AND FASCIA
A. System: Proprietary, ANSI/SPRI ES-1-tested edge metal system with rated design pressure not less than [design wind pressure as calculated per ASCE 7 for this building].
B. Material: .050 inch (1.27 mm) aluminum, ASTM B209, alloy 3003 or 3105, PVDF coil coating per AAMA 2605.
C. Nailer: Per manufacturer's tested assembly. No substitutions without Engineer's review.
D. Fasteners: Per tested assembly. Spacing as tested.
PART 3 — EXECUTION
3.1 INSTALLATION
A. Install in strict accordance with manufacturer's tested installation instructions.
B. Do not modify nailer fastener pattern or substrate without written approval from Engineer of Record.
C. Submit ES-1 test report prior to fabrication. Confirm rated pressure ≥ calculated design pressure.
Lap Joints, Expansion, and Thermal Movement
Gravel stops and fascia expand and contract with temperature changes. Thermal movement must be accommodated by correctly sized lap joints:
- Aluminum: Coefficient of thermal expansion = 0.0000128 in/in/°F. A 10-foot length experiences approximately 0.15 inch of movement over a 100°F temperature range. Lap joints for aluminum should allow minimum 1/2 inch of free movement.
- Steel: Coefficient = 0.0000065 in/in/°F. A 10-foot length experiences approximately 0.078 inch over a 100°F range. Lap joints for steel should allow minimum 3/8 inch of free movement.
- Lap joint length: SMACNA recommends minimum 3-inch laps for gravel stops; 4-inch laps for fascia over 6 inches tall.
Sealant at lap joints: Do not fully seal gravel stop lap joints with sealant — this prevents thermal movement and causes buckling. The lap joint should be fastened on one end only (the upstream, or "fixed" end), with the downstream end left free to slide. Apply sealant only to the exposed edge of the lap, not through the full depth.
Coating Specifications for Exposed Edge Metal
Exposed gravel stops and fascia on commercial buildings are typically PVDF-coated aluminum. The specification should include:
- PVDF coating system: AAMA 2605, minimum 70% PVDF resin content, 30-year color and chalk warranty
- Kynar 500 or Hylar 5000 brand designations are acceptable references; neither is required by name when AAMA 2605 is cited
- Color: As selected by Architect from manufacturer's standard range, or custom match (note: custom colors typically require minimum order quantities)
- Coating applicator: Must be approved by the coating resin manufacturer
For more on coating selection, see the PVDF vs Polyester Coating guide.
Submittal Requirements for Gravel Stop and Fascia Systems
Division 07 71 00 submittals for ES-1-tested edge metal should include:
- ES-1 Test Report: Full test report showing tested assembly (gauge, nailer, fasteners, substrate), tested pressures, and rated design pressure
- Design Wind Pressure Comparison: Calculation showing that rated pressure ≥ design pressure at the roof edge for this building
- Shop Drawings: Profile cross-sections, fascia height, nailer dimensions, fastener pattern, lap joint locations, and corner details
- Material Certifications: ASTM B209 compliance for aluminum; coating applicator certification for PVDF
- Color Samples: Physical color chips for Architect's selection and approval
- FM Approval Documentation: If FM Global requirements apply
← Back to Spec Hub · Coping Cap Anchorage Guide →
Frequently Asked Questions
What CSI section covers gravel stops and metal fascia?
Gravel stops and metal fascia at low-slope roof edges are typically specified under CSI MasterFormat Division 07 71 00 (Roof Specialties) when they are engineered systems with ANSI/SPRI ES-1 wind uplift testing, or under 07 62 00 (Sheet Metal Flashing and Trim) when custom-fabricated without proprietary wind testing. Most commercial projects use 07 71 00 for perimeter edge metal, since building code increasingly requires ES-1 compliance at roof edges.
What is ANSI/SPRI ES-1 and when is it required?
ANSI/SPRI ES-1 is the Wind Design Standard for Edge Systems Used with Low Slope Roofing Systems. It establishes test protocols for roof edge metal to verify resistance to wind uplift forces. ES-1 compliance is required by FM Global loss prevention data sheets (FM 1-49) and is referenced in the International Building Code for buildings in high-wind regions. Specifiers should require ES-1 documentation when the design wind pressure at the roof edge exceeds the capacity of standard gauge edge metal.
What is the minimum gauge for a gravel stop at a commercial low-slope roof?
SMACNA specifies minimum 24 gauge (0.0239 inch) galvanized steel or .040 inch (1.0 mm) aluminum for gravel stops at commercial roof edges. For fascia depths exceeding 4 inches, heavier gauges are required: 22 gauge (0.0299 inch) steel or .050 inch aluminum is common for 6-inch-plus fascia heights. ES-1 tested systems may have specific gauge requirements tied to their test report — always verify the test report matches the actual gauge being installed.
How does a gravel stop differ from a drip edge?
A gravel stop has a vertical or angled nailer leg embedded in or at the edge of the roof membrane, plus a vertical face projection, designed to retain aggregate surfacing on the roof while also providing a finished edge. A drip edge is a simpler profile designed only to direct water away from the fascia and into the gutter. Gravel stops are used on low-slope roofs; drip edges on steep-slope applications.
What submittals are required for ANSI/SPRI ES-1 edge systems?
For ANSI/SPRI ES-1 edge systems, Division 07 71 00 submittals typically include: the ES-1 test report showing the tested assembly and rated uplift capacity; product data from the manufacturer; shop drawings showing the edge profile, fascia height, nailer attachment, and lap joint locations; material certifications; and color samples for PVDF-coated systems. The test report must be compared to the actual design wind pressure at the roof edge to confirm the system is adequate.