Corna-Kokosing | Columbus, Ohio

Curved Double-Lock

Curved Double-Lock CR-DL20 is a structural panel which is mechanically seamed during installation. The panel is an integral interlocking system by design which installs in one direction from a given starting point. A double male* starter panel is available (for a minimal set-up fee) and may be installed in the middle of a roof area to achieve a symmetrical layout. DOUBLE-LOCK utilizes the traditional SMACNA standing seam “double-lock” plate.

DL20 Profile

Material Minimum
Convex Radius
Layover Radius
24 Ga. Steel 20′ 300′
22 Ga. Steel 20′ 300′
.032 Aluminum 20′ 220′
.040 Aluminum 20′ 220′
Copper 20′ 200

22 ga. steel panels are to be single-locked.
Stiffeners only on panels with a radius greater than 27’.

Two different clips are available
Low Floating and Fixed.

DynaClad® 70% Full Strength PVDF Paint Finish

Choice of over 32 Colors


CR-DL20 Cut Sheet









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Roof Assemblies

DOUBLE-LOCK can be applied over various roof substrates including: open framing, rigid insulation (utilizing a bearing plate under each panel clip 30” o.c., max.) over 22 ga. steel deck, and various solid substrates including plywood sheathing and nail base insulation.

Uses & Applications

Product uses include barrel vaults, curved canopies, low to high slope roofing and mansards.

*Note: Metallic paint finishes are “directional” and are not recommended for “double male” panels.

Product Offerings

24 ga. Steel, and .032 Aluminum
Embossing and various stiffener configurations available

  • DL2012 with 12″ o.c. seams
  • DL12016 with 16″ o.c. seams
  • DL2018 with 18″ o.c. seams

16, 20 oz. Copper
Various stiffener configurations available

  • DL2012 with 12″ o.c. seams
  • DL2014 with 14″ o.c. seams

24 ga (.7mm) and 22 ga (.8mm) RHEINZINK®
Various stiffener configurations available

  • DL2014 with 14″ o.c. seams

Performance Tested

  • UL-580 Wind Uplift
  • ASTM E1592 Uniform Static Air Pressure
  • ASTM E1646 Water Penetration
  • ASTM E1680 Air Leakage


  • Factory Applied Non-Curing Sealant: For superior watertightness
  • SMACNA Seam Design: A traditional and historical aesthetic appearance
  • Mechanically Seamed: May be installed on low slope applications down to 1/2:12 slope
  • Expansion Clips: Allows for thermal expansion and contraction
  • Continuous Rollformed Lengths : Eliminates need for panel lap joints
  • Total System Warranties Available: For total confidence

AIA Continuing Education

DMI is committed to providing you with high-quality expert-level education in accordance with the AIA/CES standards. The courses we offer are designed to meet the needs of architects and typically run one hour in length. All Attendees will earn 1 Learning Unit. Some of the courses offered will meet the Health, Safety, and Welfare (HSW) requirements as well as the Green Building Certification Institute (GBCI) credits.

information on available courses

Our Warranties are Second to None

DMI total system warranties protect all aspects of your metal envelope system, whether that be the watertightness of the roof or siding, the Galvalume ® steel, or the durable PVDF KYNAR® finish. When looking at warranties for your system, it is important to note that not all warranties are created equal. DMI warranties ensure the watertightness of all flashing conditions, trims, curbs, valleys, and penetrations. Building owners are protected with a total system warranty - “from the deck up” when using DMI insulation, fasteners, and underlayment. Our warranties are backed-up by a full-service Engineering Department, generating project specific shop drawings. Quality control is monitored by a minimum of two on-site inspections by our Field Technical Inspectors. DMI Total System Warranties give building owners and design professionals confidence that they are receiving the highest quality and most complete warranty available in the industry.

Browse Our Warranties