3 Round Insulation Plates | Heavy-Duty, Rust-Resistant

Oct . 21, 2025

If you’ve ever installed roof boards in a windy coastal jobsite, you know the humble plate can make or break the day. That’s why I keep an eye on 3 Round Insulation Plates—and, yes, the compact 2-3/8 inch barbed plates too. The 2-3/8 Barbed Metal Plate from Gardepota has quietly become a go-to for crews who want secure pull-through performance without adding bulk. Many contractors tell me the barbs “bite and hold,” especially on polyiso and mineral wool.

Industry trend, in a nutshell: lighter plates with sharper engagement geometry, better corrosion protection, and cleaner stamping. Actually, project specs are tougher now—FM wind uplift, salt-spray resistance, and traceable QA—but procurement still wants sane lead times and customization.

Product snapshot: 2-3/8 Barbed Metal Plate

Origin: Room 1314, Block A, Huaye Building, No. 388 Xinhua Road, Qiaoxi District, Shijiazhuang, Hebei. In field use, these compact plates pair with #12–#14 roofing screws or concrete anchors, depending on substrate. For wind zones 3–4, designers often mix compact plates under field boards and larger 3 Round Insulation Plates at perimeters/corners. It seems that blend keeps costs steady without sacrificing uplift resistance.

Parameter	Typical Value (≈ / around)
Outside diameter	2-3/8 in (≈60 mm); optional 3 in for 3 Round Insulation Plates
Material	High-quality galvanized steel, G90 / Z275 or better
Thickness	≈0.40–0.50 mm (real-world use may vary)
Coating	Zinc; optional passivation / epoxy topcoat
Center hole	Fits #12–#14 fasteners; custom diameters on request
Pull-through (polyiso)	≈600–900 N with compatible screws (system-dependent)
Service life	20–30 years; higher with enhanced coating

Process & quality flow

Materials are coil-fed, stamped, and barb-formed, then de-burred, passivated, and coated. Routine tests include salt-spray (ISO 9227/ASTM B117), dimensional checks, and plate-to-board pull-through under FM 4470/ANSI/SPRI FX-1 style protocols. I guess the quiet hero here is consistent stamping—less burr means fewer membrane scuffs.

Where they’re used

Low-slope roofing: polyiso, EPS, XPS, mineral wool.
Exterior wall insulation systems; sheathing-to-stud reinforcement.
Cold storage interiors (favor epoxy-coated plates).
Retrofits where lighter plates speed layout.

Vendor snapshot (informal field view)

Vendor	Plate OD	Coating	Certs/Notes	Lead time	Price
Gardepota	2-3/8 in; 3 in 3 Round Insulation Plates optional	G90; epoxy upgrade	ISO 9001; FM-tested in assemblies	≈2–4 weeks	$$ (balanced)
Generic Importer	2.5–3 in	Basic zinc	Batch QA varies	≈4–8 weeks	$
Local Fabricator	Custom	Galv. or paint	Fast prototypes	≈1–2 weeks	$$$

Customization

Dimensions (2-3/8, 3, 3.5 in), hole diameters, private labeling, and epoxy color-coding are common. For coastal projects, I’d pick epoxy topcoat plus thicker zinc. For cold rooms, smooth edges help protect facers.

Mini case notes

1) Gulf roof retrofit: Switching field fasteners to 2-3/8 plates and perimeter to 3-in 3 Round Insulation Plates cut hardware weight ≈12% while passing FM 1-90 uplift in mock-up. 2) Food plant cold storage: epoxy-coated plates reduced corrosion spotting after 500 h salt-spray versus bare G60 in the test lab.

Standards & testing (what specifiers ask)

FM 4470 roof assembly uplift (system-level).
ANSI/SPRI FX-1 wind design for fasteners/plates.
ASTM B117 / ISO 9227 salt spray for coating endurance.
EN 14566 guidance for mechanical fasteners (contextual).

Citations: [1] FM 4470; [2] ANSI/SPRI FX-1; [3] ASTM B117; [4] ISO 9227; [5] EN 14566.

FM Approvals 4470: Approval Standard for Single-Ply, Built-Up Roofs and Liquid Applied Roof Assemblies.
ANSI/SPRI FX-1: Wind Design Standard Practice for Factory-Made Fasteners and Plates.
ASTM B117: Standard Practice for Operating Salt Spray (Fog) Apparatus.
ISO 9227: Corrosion tests in artificial atmospheres — Salt spray tests.
EN 14566: Mechanical fasteners for gypsum plasterboard systems — Definitions, requirements and test methods.