General Specifications


Standard Sing Core Cold Rolled Steel Sliding Door Blanks are manufactured with patented Sing Core material as the base interior substrate of the door. The Sing Core substrate material is created using a vertical grain natural wood torsion box design while the traditionally empty voids are filled wall to wall with recycled foam. The foam material is available in various forms depending on your specification. The default is recycled EPS foam. Natural wood lock blocks can be positioned at locations as necessary for locking mechanism placement and/or as sliding hardware anchor points. The core material is framed by 1.25-inch wood stiles and rails for finishing strength and attaching hardware. The torsion box is completed by adhering 20 gauge cold rolled steel as exterior material (skin) according to your specifications. The man door opening is cut out to architectural specifications.

Cold Rolled Steel Sliding Door Surface Material

The door blank surface material is made of 20 gauge cold rolled steel unless otherwise specified. Bonding agent used in adhesion of the entire composite material is formaldehyde-free.

Click here for tips on How to Create the Right Sing Panel for your specific project.

Every Sing Core manufactured door blank is unfinished (unless specified otherwise) and professional grade is guaranteed for 50 years for warp-free and structural integrity.

Detailed Specifications:

Scope: Subject to local building codes, the standard Sing Core sliding door blank is intended for use in:

  • Single family dwelling interior applications
  • Multifamily dwelling, low-rise professional office, library and low-rise motel interior applications
  • Lighter use industrial building and factory, hotel and retail sales building interior applications


Cold Rolled Steel Sliding Door Materials: Sing Core cold rolled steel door blanks are manufactured using Eco-friendly cold-press process. Composite materials include:

  • Sing Core vertical wood-grain torsion substrate filled with recycled EPS foam
  • Core material is framed with solid wood stiles and rails
  • Facings are 20 gauge cold rolled steel
  • Formaldehyde-free bonding agent is used for adhesion of all components

Man Door Component: The man door leaf is created to specifications to match the large cold rolled steel sliding door and is to be fitted inside the opening in the large sliding door panel. In this case, 20 g cold rolled steel with 1.25 embedded solid wood frame and lock blocks on either side of the man door.

Architectural Specifications Substitutes

For information on some of our architectural substitutes click here.

Interior Blocking: Solid wood implants can be inserted as lock blocks or anchor points. Also additional stiles (vertical wood implants) or rails (horizontal wood implants) can be positioned at any desired location inside the cold rolled steel sliding door and man door leaf. (Note: Depending on your expectations, solid wood implants should be supported by at least 12 inches of Sing Core material to maintain true flatness.)

Delivery: Reasonable care is taken to ensure safe transportation of your Sing Core large cold rolled steel sliding door with man door from factory to your location including proper crating to protect the natural beauty of your cold rolled steel doors during transport.

Storage and Protection: Store your Sing Core large cold rolled steel sliding doors in an upright position and allow to acclimate to room temperature following shipment receipt or prior to finishing or installation.

Preparation: Per manufacturer’s specifications, ensure that openings or attachment walls are constructed plumb, true and level prior to installation. Select fasteners of adequate type, number and quality to assure proper function.

Installation: Installer shall be specialized in the installation of the type of work that is associated with the project and will comply with manufacturer’s installation policies and procedures to ensure proper end use.

Verify that attachment, hinging and latching assemblies operate freely and correctly

Finishing: The finishing of the Sing Core large cold rolled steel sliding doors and man doors are the responsibility of the client due to the product being delivered in unfinished condition unless specified otherwise in writing for use in interior applications only. Any exterior use must be approved in advance to avoid warranty exception and sealing must be in accordance with manufacturer’s specifications to protect against a variety of environmental conditions as necessary. In reference to exterior applications:

  • Seal all 6 surfaces with two coat minimum on operable panel(s)
  • Finishing or re-finishing must be completed following acclimatization and installed within 7 days
  • Avoid finishing after rain (or damp) or during periods of higher than average humidity
  • At least once a year, conduct periodic inspections of coating to ensure no wall panel components are exposed
  • Reseal the surface as necessary

Machining: Sing Core large cold rolled steel sliding doors are easy to work with in the metal shop for machining or on-site for finishing, and fastening.

Strength Performance: Patented Sing Core has an unsurpassed strength as compared to other lightweight substrate materials tested at 660 PSI (based on 2″ x 2″ grids and 3/4″ thick) for superior structural integrity and is resistant to warp, twist and crack when compared to other materials.

Light Weight Performance: Sing Core weighs much less than other traditional building materials, as much as 50% less; or more, as little as 4 lbs. per sq. ft. yet sustainable and true green technology.

Insulation Performance: Standard Sing Core sliding door blanks feature built-in insulation value with an R3 (can be upgraded to to R6.5 or more) rating per inch, depending on architect’s specifications.

Acoustical Performance: Sing Core standard sliding door blanks have a natural sound-deadening quality for noise control. Standard sound transmission class (STC) is 30. Additional noise control specifications can be met at the behest of the customer or designer and must be noted in advance.

Eco-friendly: Sing Core is manufactured using natural wood fibers, no formaldehyde, or toxic chemicals, is created using less energy than any other core material with little or no waste. The structure of Sing Core is 100% renewable (nature-grown) clean wood fiber and/or recycled material.

Warranty: Sing Core sliding door blanks come with a 10-year warranty, while professional manufactured sliding door blanks can be structurally guaranteed and warp-free for 50 years under normal conditions.

Basic Sing Door Spec Drawings: Click here

Custom-cut Window/Lite Openings: Lite openings for glass inserts can be custom cut per your specifications (drawings above show examples of standard openings) for glass insertion.

Door Specifications

Door Width
Rough Opening Width
Rough Opening Height 6/8
2/0 (Single) 26″ 82-1/2″
2/4 (Single) 30″ 82-1/2″
2/6 (Single) 32″ 82-1/2″
2/8 (Single) 34″ 82-1/2″
3/0 (Single) 38″ 82-1/2″
4/0 (Double) *50″ 82-1/2″
4/8 (Double) *58″ 82-1/2″
5/0 (Double) *62″ 82-1/2″
5/4 (Double) *66″ 82-1/2″
6/0 (Doulble) *74″ 82-1/2″

See also: Door Technical Information

Appearing regularly in Contemporary Architecture Design

* Note: STC rating varies according to size, thickness, skin, and other factors. Sing Core does not rate doors, although we are fortunate enough to have one of the best sound testing labs in the world, here in the Pacific Northwest. If you require a specific STC rating, Sing Core can build a door to your architectural specifications and have the resulting door tested at our rating facility for an official rating.