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      MasterLok-90 and MasterLok-FS Standing Seam Roof Panel

      Trapezoidal standing seam systems engineered for slopes as low as ¼:12.

      McElroy Metal’s MasterLok-90 is a snap seam panel while MasterLok-FS is a mechanically seamed option. They are both structural standing-seam roof systems engineered for quick installation, good uplift resistance and long-term durability.

      Renderings & Profiles

      Color Charts

      Great for:

      walls-icon
      WALLS
      roofs-icon
      ROOFS
      residential-icon
      RESIDENTIAL
      commercial-icon
      COMMERCIAL
      MasterLok-90 and MasterLock-90 FS
      MasterLok-90 / MasterLok-90 FS Seamed
      MasterLok-90 / MasterLok-90 FS Profile
      MasterLok-90 / MasterLok-90 FS Low Float Clipo
      MasterLok-90 & MasterLok-FS Specs at a Glance
      Panel Type
      Rib Height
      Major Rib On Center
      Cover Width
      Factory Panel Length
      Onsite Forming Available
      Substrate/Gauges
      Installation
      Finishes
      Minimum Slope
      Concealed fastener standing seam
      3"
      24”
      24”
      Up to 85' (varies by manufacturing facility)
      No
      24 GA Galvalume®
      Solid Deck or Open Framing
      Kynar 500® (PVDF); Galvalume® Plus (acrylic-coated)
      1/4:12

      MasterLok-90 & MasterLok-FS Ideal Applications

      • Low- to steep-slope roofing for commercial, industrial, and institutional facilities without hips and valleys.

      • Pre-engineered applications that require a cost-effective approach while delivering strong performance.

      • Retrofit and new-construction projects seeking structural integrity and design flexibility.

      • Institutional or civic buildings where long-term aesthetics and performance are equally important.

      See 3D Textures Here
      MasterLok-90 Ideal Application
      MasterLok-90 Ideal Application
      masterlok-90-ideal-application-3

      MasterLok-90 & MasterLok-FS Top 3 Benefits

      1. Versatile Installation Options: Can be installed over open framing or solid decking; available with standard or high-clip systems to accommodate varying insulation thicknesses.

      2. Durable Finish and Material Options: Manufactured from Galvalume® steel in 24 GA with a Kynar 500® (PVDF) coating for outstanding color retention and corrosion resistance.

      3. Lower First Cost Investment: The trapezoidal shape and 24” coverage, help it offer one of the lowest installed price points for roofs down to ¼:12.

      Color Charts

      MasterLok-90 & MasterLok-FS Color Chart Architectural Color Chart

      CAD Drawings

      MasterLok-90 Low Floating End Lap Detail MasterLok-90 Low Floating Hi-Side Tie-In Detail MasterLok-90 Low Floating Rake End (Off Module) Detail MasterLok-90 Low Floating Rake End Detail MasterLok-90 Low Floating Rake Start Detail MasterLok-90 Low Floating Rake Start Tie-In (Off Module) (Alt.) Detail MasterLok-90 Low Floating Rake Start Tie-In Detail MasterLok-90 Low Floating Ridge Detail MasterLok-90 Low Fixed Eave Detail MasterLok-90 Low Fixed Eave with Gutter Detail MasterLok-90 Low Fixed High Eave Detail MasterLok-90 Low Fixed Hi-Side Tie-In Detail MasterLok-90 Low Fixed Rake End (Off Module) Detail MasterLok-90 Low Fixed Rake End Detail MasterLok-90 Low Fixed Rake Start Detail MasterLok-90 Low Fixed Rake Start Tie-In Detail MasterLok-90 Low Fixed Ridge Detail MasterLok-90 Low Fixed Sculptured Eave Detail MasterLok-FS Low Floating End Lap Detail MasterLok-FS Low Floating High Eave Detail MasterLok-FS Low Floating Hi-Side Tie-In Detail MasterLok-FS Low Floating Rake End (Off Module) Detail MasterLok-FS Low Floating Rake End Detail MasterLok-FS Low Floating Rake Start Detail MasterLok-FS Low Floating Rake Start Tie-In (Off Module) Detail MasterLok-FS Low Floating Rake Start Tie-In Detail MasterLok-FS Low Floating Ridge Detail MasterLok-FS Low Fixed Eave Detail MasterLok-FS Low Fixed Eave with Gutter Detail MasterLok-FS Low Fixed Hi-Side Tie-In Detail MasterLok-FS Low Fixed Rake End (Off Module) Detail MasterLok-FS Low Fixed Rake Start Detail MasterLok-FS Low Fixed Rake Start Tie-In Detail MasterLok-FS Low Fixed Ridge Detail MasterLok-FS Low Fixed Sculptured Eave Detail

      PDF Drawings

      MasterLok-90 Low Floating End Lap Detail MasterLok-90 Low Floating Hi-Side Tie-In Detail MasterLok-90 Low Floating Rake End (Off Module) Detail MasterLok-90 Low Floating Rake End Detail MasterLok-90 Low Floating Rake Start Detail MasterLok-90 Low Floating Rake Start Tie-In (Off Module) (Alt.) Detail MasterLok-90 Low Floating Rake Start Tie-In Detail MasterLok-90 Low Floating Ridge Detail MasterLok-90 Low Fixed Eave Detail MasterLok-90 Low Fixed Eave with Gutter Detail MasterLok-90 Low Fixed High Eave Detail MasterLok-90 Low Fixed Hi-Side Tie-In Detail MasterLok-90 Low Fixed Rake End (Off Module) Detail MasterLok-90 Low Fixed Rake End Detail MasterLok-90 Low Fixed Rake Start Detail MasterLok-90 Low Fixed Rake Start Tie-In Detail MasterLok-90 Low Fixed Ridge Detail MasterLok-90 Low Fixed Sculptured Eave Detail MasterLok-FS Low Floating End Lap Detail MasterLok-FS Low Floating High Eave Detail MasterLok-FS Low Floating Hi-Side Tie-In Detail MasterLok-FS Low Floating Rake End (Off Module) Detail MasterLok-FS Low Floating Rake End Detail MasterLok-FS Low Floating Rake Start Detail MasterLok-FS Low Floating Rake Start Tie-In (Off Module) Detail MasterLok-FS Low Floating Rake Start Tie-In Detail MasterLok-FS Low Floating Ridge Detail MasterLok-FS Low Fixed Eave Detail MasterLok-FS Low Fixed Eave with Gutter Detail MasterLok-FS Low Fixed Hi-Side Tie-In Detail MasterLok-FS Low Fixed Rake End (Off Module) Detail MasterLok-FS Low Fixed Rake Start Detail MasterLok-FS Low Fixed Rake Start Tie-In Detail MasterLok-FS Low Fixed Ridge Detail MasterLok-FS Low Fixed Sculptured Eave Detail

      English Installation Manuals

      MasterLok 90 Installation Manual MasterLok FS Installation Manual

      Spanish Installation Manuals

      MasterLok 90 Installation Manual

      Brochures/Flyers

      MoistureLok Flyer 2025 Product Catalog Standing Seam Clip & Thermal Spacer Guidelines

      Metal Panel Care & Maintenance

      Oil Canning Tech Sheet from MCA Operation and Maintenance Manual (Roofs)

      Product Data Sheets

      MasterLok 90 Product Data MasterLok FS Product Data SikaLastomer® 511 Product Data

      Product & Trim Information Books

      Masterlok 90/Masterlok FS Product Information Book

      SDS - Substrate & Paint

      Galvalume® Substrate Paint - Almond Paint - Ash Gray  Paint - Bone White  Paint - Brandywine  Paint - Brite Red  Paint - Buckskin Paint - Champagne Metallic Paint - Charcoal  Paint - Colonial Red  Paint - Copper Penny  Paint - Dark Bronze Paint - Evergreen  Paint - Hartford Green  Paint - Home Depot Orange Paint - IHOP Blue Paint - Leadcoat Paint - Mansard Brown  Paint - Matte Black Paint - Medium Bronze Paint - Patina Green Paint - Patrician Bronze Paint - Preweathered Galvalume® Paint - Regal Blue Paint - Regal White Paint - Roman Blue Paint - Sandstone Paint - Silver Metallic Paint - Slate Gray Paint - Surrey Beige Paint - Texas Silver Metallic Paint - White Backer  Paint Pens - Kynar® Paint Pens- Kynar® ADS Data

      Specifications

      MasterLok-FS MasterLok 90

    • MasterLok-90 - 18"

      Customize (Recommended) Download All

      • Customize your submittal package MasterLok-90 - 18"

      Click on your desired documents below to select them for your package.

      General Product and Warranty Information

      Panel Load Tables w/Section Properties and Testing

      Safety Data and Material Safety Data Sheets

    • MasterLok-90 - 24"

      Customize (Recommended) Download All

      • Customize your submittal package MasterLok-90 - 24"

      Click on your desired documents below to select them for your package.

      General Product and Warranty Information

      Panel Load Tables w/Section Properties and Testing

      Safety Data and Material Safety Data Sheets

    • MasterLok-FS - 18"

      Customize (Recommended) Download All

      • Customize your submittal package MasterLok-FS - 18"

      Click on your desired documents below to select them for your package.

      General Product and Warranty Information

      Panel Load Tables w/Section Properties and Testing

      Safety Data and Material Safety Data Sheets

    • MasterLok-FS - 24"

      Customize (Recommended) Download All

      • Customize your submittal package MasterLok-FS - 24"

      Click on your desired documents below to select them for your package.

      General Product and Warranty Information

      Panel Load Tables w/Section Properties and Testing

      Safety Data and Material Safety Data Sheets

      UL 580 Construction Numbers

      MasterLok-90 #205 (open framing) MasterLok-FS #538 (open framing) MasterLok-FS #539 (metal deck)

      ASTM E283 (Air) & ASTM E331 (Water)

      ASTM E283/E331 - MasterLok-90 w/Endlap 

      Approvals

      Factory Mutual Approval MasterLok FS 24 Fire Resistance (UL263) Ratings Fire Resistance (UL790) Ratings Florida Product Approvals Non-Structural Florida Product Approvals Structural Impact Resistance (UL 2218) Class 4

      ASTM E1592 Uplift Tests

      MasterLok-90 22 Ga. MasterLok-90 24 Ga. MasterLok-FS 22 Ga. MasterLok-FS 24 Ga.

      Panel Load Tables w/Section Properties

      MasterLok-90 Load Tables 18" 22 Ga. 50 KSI MasterLok-90 Load Tables 18" 24 Ga. 50 KSI MasterLok-90 Load Tables 24" 22 Ga. 50 KSI MasterLok-90 Load Tables 24" 24 Ga. 50 KSI MasterLok-FS Load Tables 18" 22 Ga. 50 KSI MasterLok-FS Load Tables 18" 24 Ga. 50 KSI MasterLok-FS Load Tables 24" 22 Ga. 50 KSI MasterLok-FS Load Tables 24" 24 Ga. 50 KSI

      Miscellaneous Information

      99-418-23 Curb Requirements for WTW

      Finish and Substrate Warranties

      Standard Galvalume® Standard Fluropon® Kynar 500® PVDF with Galvalume® Substrate Project Specific Galvalume® Project Specific Fluropon® Kynar 500® PVDF with Galvalume® Substrate

      Weathertightness Warranties

      WTW - Joint NRL (Certified Installer) WTW - Joint Sample WTW - Single Source NRL Sample (Certified Installer) WTW - Single Source Sample (Certified Installer)

      Compare our standing seam panels using the tool below.

      For information on all McElroy Metal products, visit our full product library.


      Panel
      Seam Type
      Rib Height
      Panel Widths
      Minimum Slope
      Install Substrate
      Clips
      Substrate / Gauges
      Coating
      Notable Approvals / Tests
      MasterLok-90 & MasterLok-FS
      N/A
      3"
      24”
      1/4:12
      Solid Deck or Open Framing
      N/A
      24 GA Galvalume®
      Kynar 500® (PVDF); Galvalume® Plus (acrylic-coated)
      UL 263 Class A; UL 580 Class 90 (MasterLok-FS only); UL 2218 Class 4 (MasterLok-FS only); ASTM E1592; Florida Product Approval; FM 4471 (MasterLok-FS only)

      Components Gallery

      4_709x600

      ML-90 Low Fixed Clip (Utility Fixed & High Fixed Clips also Available)

      ML90LowFloatClip-sized-1

      ML-90 Low Floating Clip (High Floating Clip also Available)

      1_709x600

      ML-FS Low Floating Clip (High Floating & Tall Floating Clips also Available)

      ML90LowFloatClip-sized

      ML-90 Low Fixed Clip (Utility Fixed & High Fixed Clips also Available)

      seams_masterlock-fs_before_BLUE_HR

      MasterLok-FS Before Seaming

      seams_masterlok-fs_seamed_BLUE_HR-1

      MasterLok-FS After Seaming

      seams_masterlok-90_BLUE_HR

      MasterLok-90 After Seaming

      4_709x600

      ML-90 Low Fixed Clip (Utility Fixed & High Fixed Clips also Available)

      ML90LowFloatClip-sized-1

      ML-90 Low Floating Clip (High Floating Clip also Available)

      1_709x600

      ML-FS Low Floating Clip (High Floating & Tall Floating Clips also Available)

      ML90LowFloatClip-sized

      ML-90 Low Fixed Clip (Utility Fixed & High Fixed Clips also Available)

      seams_masterlock-fs_before_BLUE_HR

      MasterLok-FS Before Seaming

      seams_masterlok-fs_seamed_BLUE_HR-1

      MasterLok-FS After Seaming

      seams_masterlok-90_BLUE_HR

      MasterLok-90 After Seaming

      Weathertightness Warranties

      If your project requires a Weathertightness Warranty and you don’t already have a job specific Pre-Approval Form issued by McElroy Metal, click the button below to get started.

      Learn More

      Shop Drawing Service

      Running short of time to complete your own shop drawings? McElroy Metal can help. Click the button below to provide us some basic information and we’ll be in touch soon to discuss your project specifics.

      Contact Us

      Download Shop Drawings

      If you’re creating your own shop drawings, click the button below to gain full access to our CAD and PDF Files.

      View Drawings
      moisturelok-logo-2026

      Factory Applied Anti-Condensation Membrane

      MasterLok-90/MasterLok-FS roof panels with McElroy's MoistureLok, offer a great option to address condensation challenges. The design of our MoistureLok product traps moisture and then releases it back into the air as natural humidity once conditions go back below the dew point.

      Learn More
      Peachtree Solar-501-1

      Notes & Manufacturing Locations

      • Manufactured in Bossier City, LA; Clinton, IL; Winchester, VA; Ashburn, GA

      • Panels include factory-applied sealant

      • Available with MoistureLok anti-condensation membrane

      • Best suited for simple sloped roofs without dormers, hips, valleys or other special conditions

      • Additional Material Options: (Note: Minimum quantity and additional lead-time may apply)

        • 22 GA Galvalume® steel

      • Oil canning is a natural occurrence in metal panels and not a cause for rejection.

      McElroy Logo Emp Ownd Opt1_BLK-RED

      Why Choose McElroy Metal

      McElroy Metal is an employee-owned manufacturer with more than six decades of experience producing high-quality metal roofing, wall systems, and substructural components. Our nationwide manufacturing and service center network ensures consistent availability, responsive support, and dependable delivery. Built on a culture of craftsmanship and partnership, our products are engineered for long-term durability and trusted performance on projects of every size.

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      Find a Distributor / Contractor Near You

      Whether you’re building a new home or planning renovations, a metal roof can deliver long-term cost savings and comfort. To explore your options and find the product that meets your aesthetic and budgetary needs, contact a McElroy Metal distributor or contractor in your area today. We can’t wait to help make your dream home a reality.

      Find a Contractor

      Frequently Asked Questions

      The questions below address common considerations and help guide product selection for your project.

      What finish options are available?
      Standard finishes include Kynar 500® (PVDF) coatings on 24 GA Galvalume® substrate, providing exceptional color retention and weather protection. For non-painted applications, we offer Galvalume® Plus (acrylic-coated). Learn More
      What makes MasterLok-90 and MasterLok-FS different from Maxima panels?
      MasterLok-90 and MasterLok-FS are trapezoidal standing seam systems, while Maxima features a vertical leg profile. Trapezoidal panels, such as the MasterLok series, offer a 24" cover width and install more quickly with less packaging, offering a cost-effective option. Vertical leg systems like Maxima, however, can provide enhanced uplift performance depending on project requirements.
      Can the MasterLok-90 series be used over open purlins?
      Yes. Both panel options can be installed over open framing or solid decking with concealed clips that allow thermal movement.
      What is the minimum roof slope for the MasterLok-90 series?
      ¼:12 when mechanically seamed, ensuring watertight performance for low-slope designs.
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