What Is a Gravel Stop?
A gravel stop is the perimeter edge profile installed around the edge of a flat or low-slope roof. Its name comes from its original function on built-up roofing (BUR) systems: the raised vertical flange at the edge prevents gravel or crushed stone ballast from rolling off the roof. On modern single-ply membrane roofs (TPO, EPDM, PVC), the "gravel stop" is technically a roof edge profile that terminates the membrane and provides a finished fascia appearance — even when there's no ballast to stop.
The gravel stop is also the primary wind uplift resistance component at the roof edge. ANSI/SPRI ES-1 governs the testing and specification of edge metal systems for wind uplift resistance, and compliance is required on most commercial projects.
Gravel Stop Profile Geometry
A standard gravel stop has four key elements:
- Nailer flange (horizontal leg) — lies back on the roof deck or cover board, typically 2"–4" wide, through which fasteners are driven at 6"–12" on center
- Face height (vertical leg) — the vertical portion that forms the visible fascia face of the roof edge; height is determined by the roof assembly thickness plus a minimum 1" above membrane surface
- Top return (receiver hook) — a small horizontal return at the top of the face, typically ¾"–1", that captures the membrane termination and provides the drip break
- Bottom hem — a hemmed return at the bottom of the face leg for stiffness and safety at the exposed cut edge
Face Height Selection
Face height is the most critical dimension on a gravel stop. It must be tall enough to rise above the finished roofing system by at least 1" while concealing the substrate below. Key reference heights:
| Roof Assembly | Assembly Thickness | Typical Face Height |
|---|---|---|
| Recover over existing BUR (no tear-off) | 1½"–2½" | 3"–4" |
| 2" polyiso + membrane (new) | 2½" | 4" |
| 3" polyiso + cover board + membrane | 4"–4½" | 5"–6" |
| 4"+ polyiso (high R-value) | 5"–6" | 6"–7" |
| Tapered insulation (average) | Varies | Field measure required |
Always field-measure before ordering. Assembly heights vary by insulation type, quantity, and any existing roofing that is being recovered over. A 1" error in face height is immediately visible on a finished building.
ANSI/SPRI ES-1 Compliance
ANSI/SPRI ES-1 is the industry standard governing edge metal systems for wind uplift. It specifies minimum metal thickness, fastener spacing, and joint details based on the design wind speed for the project location. Key ES-1 requirements:
- Face height up to 6": minimum .050" aluminum or 24 ga. steel
- Face height 6"–8": minimum .063" aluminum
- Nailer flange fastener spacing: per the ES-1 table for design wind speed
- Joints: 3" minimum lap with sealant and cover plate
Most commercial specifications require ES-1 compliance documentation. Trimgy's cross-section drawing captures the geometry; material thickness and fastener spacing per ES-1 are the contractor's responsibility to verify.
Materials and Thicknesses
| Material | Thickness | Application |
|---|---|---|
| Aluminum | .050" | Commercial standard, face heights up to 6" |
| Aluminum | .063" | High-wind zones, face heights over 6", SPRI ES-1 compliance |
| Galvalume steel | 24 ga. | Budget commercial where aluminum cost is a constraint |
| Stainless steel | 24 ga. | Aggressive coastal environments with high chloride exposure |
How Trimgy Handles Gravel Stop
Gravel stop is one of the most frequently custom-ordered profiles on Trimgy. The face height changes on every re-roofing job depending on the existing assembly height and the new insulation added. Standard stock profiles don't accommodate job-specific face heights — and getting this dimension wrong wastes material, delays the job, and results in a visible error on a prominent commercial building.
With Trimgy, you measure the field dimension, enter it into the drawing grid, and order a profile that matches the actual condition. The AI can draft the profile from a description: "gravel stop, 5" face, 3" nailer flange, top receiver hook, .050 aluminum." The order transmits directly without re-interpretation.
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Start Drawing Free →Frequently Asked Questions
What is the difference between a gravel stop and a roof edge?
A gravel stop has a raised flange to retain ballast on BUR systems. A roof edge is any perimeter profile on a flat roof, including membrane termination profiles on single-ply systems that don't retain ballast. The terms are often used interchangeably in the field.
What face height should I specify?
Face height equals the total roof assembly thickness (insulation + cover board + membrane) plus a minimum 1" above the membrane surface. Always field-measure; assembly heights vary significantly by project.
What aluminum thickness is required?
ANSI/SPRI ES-1 requires .050" minimum for face heights up to 6" in most commercial applications. High-wind zones or face heights over 6" require .063". Verify against ES-1 for your project's design wind speed.
How is gravel stop attached to the roof edge?
Through the nailer flange at 6"–12" on center per ES-1. The membrane is stripped in over the nailer flange. Joints are lapped 3" with sealant and a cover plate.
What is the typical price for custom gravel stop?
.050" aluminum gravel stop runs $7–$14/LF for material depending on face height. Kynar paint adds 35%–50%. LTL freight on a 300–600 LF order adds $400–$900.