SnoBar Double Bar Snow Rail System – Screw Down for Exposed Fastener Metal Roofs – (6 Foot) Galvanized Gator Shield

SnoBar Double Bar Screw Down Snow Rail for Exposed Fastener Metal Roofs - Galvanized, 6 Foot

Why Contractors Specify the Double Bar Screw Down SnoBar

• Double bar capacity - two continuous 1" square bars per row for higher snow load.
• Gator Shield galvanized coating with 50% more zinc than standard galvanizing
• Built for exposed fastener metal roofing - PBR, R-panel, AG panel, 5V Crimp, Tuff Rib, Classic Rib, U-panel and similar through-fastened profiles
• 16-gauge Gator Shield steel bars paired with mill aluminum brackets that will not rust or corrode
• Project-specific spacing layout guidance with every order - eliminates guesswork on row count and bracket spacing
• Made in the USA with 30+ years of laboratory and field-proven performance behind every component

Product Overview

The SnoBar Double Bar Screw Down Snow Rail is the heavy-duty configuration of the original SnoBar snow retention system, purpose-built for exposed fastener metal roofs. Two Gator Shield galvanized 1" square steel bars run continuously across the roof, mechanically fastened through the panel into the structural purlin below. Contractors specify this double bar configuration when single bar snow rails may not provide enough retention for the roof conditions - commercial buildings, steep-slope roofs, heavy-snow regions, and any roof where a slide event creates liability exposure.

This is the correct snow retention system for metal roofs that use exposed fasteners rather than concealed-fastener standing seam. Screw down panels - PBR, R-panel, AG panel, 5V Crimp, Tuff Rib, Classic Rib and similar ribbed through-fastened profiles - do not have the raised seam geometry that clamp-mounted snow guards require. The proper attachment on these roofs is a mechanically fastened bracket (MRM BRACKET) that penetrates the panel and anchors into the purlin. 

How the Double Bar Snow Rail System Works

A properly designed snow retention system distributes retained snow load evenly across the entire roof plane. Continuous snow bars in rows from eave to ridge hold accumulated snow and ice in place so it melts and releases gradually rather than sliding off as an avalanche. When every panel carries its share of the load, no single fastener, purlin, or panel section is overloaded.

Double bar outperforms single bar for three reasons. Cross-sectional area - two 1" square bars present roughly twice the physical barrier to sliding snow. Load distribution - retained snow transfers into the brackets across two bearing surfaces instead of one, reducing point stress at each attachment. Slide behavior - the lower bar catches the initial slide event, the upper bar stops any snow that rides over the first. On commercial roofs, steep pitches, and heavy-snow regions, this is what separates a system that holds from one that fails.

What's Included

• (2) 6-foot 1" square Gator Shield galvanized steel SnoBar rails
• MRM mounting brackets - fastened through the panel into wood or steel purlins
• Screw Down 2-Bar Bracket (SC2B) - mounts to the top of the MRM bracket to hold both bars
• #14 woodgrip or self-drilling metal-to-metal fasteners with bonded sealing washers
• Tek screws / retaining hardware to secure bars in the SC2B bracket
• Black polyethylene end caps to seal bar ends
• All hardware required for installation - kit ships complete

Exposed Fastener Panel Compatibility

The double bar screw down SnoBar is compatible with virtually all exposed fastener metal roofing panels - PBR, R-panel, AG panel, 5V Crimp, Tuff Rib, Classic Rib, U-panel and most ribbed through-fastened profiles.

For manufacturer-specific panel profiles and confirmed compatibility, see the full Snow Guard Compatibility by Roof Manufacturer guide.

Installation Overview

The screw down 2 bar SnoBar installs in a straightforward sequence. This overview is intended to help customers understand the general installation process before ordering. Always follow the current manufacturer installation instructions supplied with your order and the project-specific layout provided for your roof.

Required Tools

• Drill / impact driver with 3/8" nut driver for #14 screws
• 9/16" hand wrench for SC2B bracket top bolt
• 3/16" Allen bit for set screws
• Tape measure, chalk line, pencil
• Hacksaw and deburring file for field cuts
• Hammer for plastic end caps

Installation Sequence

1. Confirm the layout. Use the project-specific spacing layout provided with your order. If no layout was supplied, contact SnoBlox-SnoJax before installation. Every row must land on a structural purlin.
2. Locate purlins and mark fastener positions. Most through-fastened roofs have visible panel screws aligned with each purlin - use those as a guide. Mark base locations along the row with chalk line or pencil.
3. Set the MRM bracket on the panel flat between minor ribs, centered over the purlin, with bar receivers facing upslope. Drive #14 woodgrip screws for wood purlins or self-drilling metal-to-metal screws for steel purlins through every fastener hole in the base. Seat fasteners so the bonded washer just compresses - do not overdrive.
4. Install the Screw Down 2-Bar Bracket (SC2B) on top of each MRM bracket. Tighten the top bolt with a 9/16" hand wrench.
5. Repeat across the row at the recommended spacing - typically 12" to 18" on center depending on snow load, panel type, and purlin spacing. Every base must land on a purlin.
6. Slide the lower bar through the lower receiver of every SC2B base in the row, then slide the upper bar through the upper receiver. Bars must seat fully and run continuously. Do not extend more than 3" past the last base.
7. Secure the bars with the supplied Tek screws and retaining hardware.
8. Position SnoBar butt joints correctly. Butt joints must be centered between two bases with no more than a 2" gap at the ends. Short sections must span at least two bases - never clamp a short bar to a single base.
9. Install black polyethylene end caps at each bar end. Deburr any field-cut bars before capping.
10. Lay out additional rows according to the project-specific spacing layout, always landing each row on a purlin.

Design Conditions

• Load path: All loads are transferred through the panel into the purlins. Proper panel attachment and adequate purlin capacity are required. New and existing structures must be evaluated to confirm they can carry retained snow loads.
• Minimum panel: 26-gauge steel over wood purlins or 24-gauge over steel purlins, with panel fasteners correctly installed at the panel manufacturer's recommended spacing. Do not install on panels with loose, pulled, or under-driven fasteners - correct panel attachment first.
• Base spacing: Typically 12" to 18" on center, varies by snow load, panel type, and purlin spacing. Bases may only be placed where they can be fastened through the panel into a purlin.
• Eave overhang: Where there is an overhang at the eave, confirm the overhang can hold the retained snow load - otherwise place the first row at the bearing wall or first purlin.
• Isolated areas: Not recommended for doorways, vents, or partial roof sections. Call for special design considerations.
• Coverage: No snow retention system retains 100% of snow and ice. The system is designed to mitigate the dangers of sliding snow and ice.

Technical Specifications

The SnoBar Difference

Gator Shield Galvanized Coating

Gator Shield galvanized steel uses 50% more pure Western-grade zinc than standard Flo-Coat galvanizing, producing bars with yield strength of at least 50 ksi and tensile strength of 55 ksi. This heavy galvanized finish helps protect the bars against long-term corrosion when installed as directed.

Structural Attachment, Not Panel-Only

Low-cost snow retention systems screw into panel ribs or use a folded strip of panel steel stitched to the roof. Both methods can fail under load because metal roof panels alone are not intended to carry retained snow. The double bar screw down SnoBar mounts through the panel into the purlin, the correct attachment method on exposed fastener roofs.

Field-Proven Since 1992

SnoBar was the original snow rail system. The screw down configuration has protected exposed fastener metal roofs on commercial, industrial, and agricultural buildings across North America for over 30 years.