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Only Warp-free Large Door Guaranteed

Warp free large sliding doors by Sing Core

“I love these doors.” *

This photo depicts the installation of some of our latest warp-free large sliding doors. These Eco-friendly lightweight, high-strength professional Sing large sliding doors are 12 ft. tall, 68 inches wide and only 1.5 inches thick, and guaranteed not to warp, bend, twist or structurally fail for a full 50 years. When we say lightweight and high-strength, we mean it. For example, these Birch (1/4″ facings) large sliding doors weigh in at 150 lbs. per architectural specifications of Carol A. Wilson FAIA.

* = Linda Rice of Kercor Construction

The Only Warp-free Large Door Guaranteed

Large doors used in high end construction, luxury homes and mansions cost between $10,000 and $50,000 and all of them either are guaranteed to warp or guaranteed not to warp for (at the most) one year… except for one.

Our #1 job is to serve the door companies who make the best doors, so they can deliver warp-free doors to their most discriminating clientele.

$20,000 Door + 1 year = Warped Door

Warping large doors are burning moneyWhen a customer requests and the architect specifies a large door, especially a large sliding door or large pivot door, most door manufacturers will be reluctant to build it. If they do build it, they are not likely to offer a warranty for warping or structure failure because, unfortunately, large doors will warp.

Some offer a one year warranty and charge an extremely high professional for the large door, because they know it is likely that the door will warp. They install the door and pray… after one year has passed (either with or without service calls to straighten the door due to seasonal changes), they wipe the sweat from their forehead, then the burden for maintenance of the large door fall on the customer.

Large doors present a high degree of challenges because large doors (over 7 ft. tall) will warp.

The Only Warp-free Doors

Guaranteed for 50 Years

True Flat Guarantee premium certified true flatEvery door manufacturer who has sought out Sing Core as their large door solution knows there is no other way to make a hassle-free non-warping large door.
In fact, Sing Core door substrates are the only composite door core material that can be guaranteed not only to be warp-free but also maintain full structural integrity for a full 50 years.

High-end Door Manufacturer’s Secret Ingredient

Sing Core works with high end door manufacturers and millworks specializing in the most exotic oversized (therefore problematic) doors.

“When the door manufacturer calls us, they know, we know, everyone knows that custom large doors will warp. We help them solve the problem so they can deliver a product that will not fail to their clients who desire only the best doors without fear of warping.”

If you’re seeking out a high-end door that does not warp, ask your door manufacture to build your door with Sing Core Inside.

Infinite Structure

Patented Sing Core infinite torsion box 2x2 structure grids insulation

Infinite 2×2 in. grids filled with rigid foam

Sing Core’s internal vertical grain torsion box structure is reduced to form 2 inch x 2 inch grids and the torsion box voids (empty spaces) are not left empty; they are filled wall-to-wall with rigid foam insulation to add shear strength and form a high precision (.006 in. tolerance) solid composite substrate. The grids run infinitely in all directions throughout the door core resulting in a warp-free, lightweight (a fraction the weight of other heavier materials), high strength (660 PSI) that is pre-insulated (R3.5-R5.5).

Is There Any Other Way to Make a Warp-free Door?

Yes. There are many ways to make a steel door that does not warp. These large steel doors are extremely heavy (thousands of pounds). To address the issue of weight, lighter weight steel doors are made by using a steel frame (with internal steel pipe substructure) welded to thick steel exterior to make the steel door lighter than a solid steel door.

10 ft x 5 ft x 2.25 inch center pivot door solid maple wood stave warp free

Solid Maple Wood Stave 10 ft. x 5 ft. x 2 1/4 in. Warp Free Center Pivot Doors

Even so, not only is the resulting door still extremely heavy, it is hollow in between the inner steel structure. This space between the inner steel framing is left open, i.e., hollow. There could be 8 to 12 inches between steel bars (or other type steel interior frame) of nothing, only hollow space.

Normally, steel doors – while they may not be a problem for warping – are less high precision due to all the interior welding necessary to manufacture the steel door. To increase the steel door’s precision, the door can be made slightly oversize and machined to straighten the surface area imperfections.

Sing Steel Doors

On the other hand, steel doors made with solid Sing Core door substrate are Eco-friendly, lightweight, high strength and high precision (Sing Core is +/- .006) as well as fully insulated for temperature/climate control and sound deadening qualities. See: Steel Doors

New Large Door Technology

Eco-friendly Sing Core technology is changing the landscape of all large door manufacturing. Sing door core substrate can be used to manufacture any type or style of door in any size (up to 50 ft.) with any exterior material, including wood doors made of any available natural wood species, aluminum doors, ceramic doors, concrete doors, fiberglass doors, glass doors, HPL doors, Kevlar doors, Masonite doors, plastic doors, steel doors (cold rolled steel doors, galvanized steel doors, hot rolled steel doors, etc…), just to name a few…

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How to Build the Most Advanced Door in the World

Non warp door blank for building non warping doors of any sizeYou could be one of the best door builders by outsourcing your OEM non warping door blanks.

Sing Core has served the building industry by providing the only Eco-friendly, insulated non-warp high-strength, lightweight door. Contractors who build Sing Homes (entire homes built of Sing products) want the added strength, stability, insulation and non-warping doors in all egress points for added safety and security.

First, we have to talk about what makes the best door in the world; it has to be:

1 Non Warp

Even the very challenging doors, large doors, sliding doors, pivot doors, all can be warp-free. In fact SingCore creates unfinished premium doors that can be guaranteed for 50 years. The secret of the best door makers in the world is that they can use the Sing solution as their door’s base material to create a warp-free door, which is the best solution to the problem of warping doors, especially large doors which would otherwise be extremely prone to warp.

2 Lightweight, high strength, insulated and Eco friendly

The strongest lightweight door in the world is made with Sing Core inside. This revolutionary Eco-friendly building material is based on patented technology that is the best of old wood craftsmen’s technology (torsion box) and new composite technology (recycled rigid foam insulation) fused with advanced adhesives and enhanced with patent pending non-warp stiffeners. The result is an extremely lightweight panel that can span distances without deflection that has not been accomplished before in any affordable manner.

3 Easy to Install

Even the largest strongest sound deadening door can be installed in half an hour. This 500 pound Sing pivot door panel measures 10 ft. tall x 12 ft. wide x 3.5 inch thick and took less than half an hour to install in the Seattle Center for Architecture and Design.

Then, we will explain how to build the perfect door, step-by-step, showing the pictures of the entire process (even the most complicated French door, sliding door, pivot door, exterior door, etc…) with all types of skins/surface material.

How to build a patented Sing French door

Here’s how it’s done: Purchase a Sing door panel decide on custom lite cutout design and hire a pre-hung door company or millwork to install lite, hardware, sand and finish, then deliver the resulting door to your job site or customer.

Photo Tutorial

How to create lite openings for glass installation

How to add hardware for doors / French doors

Mini Large Door Gallery

The size of the average non-warp guaranteed Sing door is 9 to 14 ft tall and/or 6 to 8 ft wide.

How to build a hinged door – How to build a non warp hinge door – How to build a sliding door slab with glass – How to build a pivot door panel – How to build a flush door – How to build a carriage door


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OEM Door Original Equipment Manufacturer

Copper door Sing Core inside

Sing Core inside

Sing Core is in the unique position to partner with the designers, architects, custom millworks, builders and installers of the best doors in the world. What do the best high precision, lightweight, high strength, guaranteed warp-free doors in the world have in common? The best ones have Sing Core™ inside. See: Clients list

In this respect, Sing Core is an important OEM supplier likened to Briggs & Stratton, BBS Wheels, Johnson Controls, Lear, Delphi, TRW, Intel and AMD. These companies, like Sing Core, do not manufacture the end product but supply the product manufacturers with the quality components that enable their clients to deliver superior results to their customers without having to create separate production facilities for building specialized parts.

Even though Sing Core does not build doors, our OEM door blanks help the best door manufacturers create the best doors that are built to last for centuries and can be guaranteed not to warp, bend twist or otherwise fail for a full 50 years for their intended (designed and built) use.

Why Sing Core is the perfect solution for problem doors lightweight high strength non warp doorSee also: How to Build a Sing Door

How Does the Sing OEM Process Work?

Establishing the Need of Sing Core

There are many reasons that door manufacturers seek out patented Sing Core as their OEM door substrate; some of the most popular ones are:

Sing doorway to a better door 50 year non warp guaranteeCreating a Superior Door Line

Some door manufacturers are looking for ways to distinguish themselves from other door manufacturers. They seek out an OEM relationship with Sing Core to design and build an ultra premium line of doors that have unique characteristics that cannot be found by using any other door substrate material.

BIG Door

Many door manufacturers have problems with large doors (especially over 7 ft. tall) in that while they look magnificent upon installation, dealing with door warp on a regular basis is a constant maintenance cost associated with big doors.

Oversized large paint grade Sing pivot door panelThis is where Sing Core door substrates shine because the substructure of the core itself is a combination of wood torsion box (using vertical grain matrix framing) filled with recycled rigid foam creates a lightweight, high strength solid substrate that will retain its original shape and structural integrity over time; higher precision and lasts longer than any other known door building material.

That’s why more and more, you are finding Sing Core™ inside some of the biggest aircraft hangar doors, large sliding barn doors, factory doors, large commercial doors, warehouse doors and large garage doors.

Non-warp Door

Sing Core™ is the only door core material that enables our door manufacturers to deliver doors that do not warp regardless of size or external materials in either interior and/or exterior doors, if they are designed by our Non-warp True Flat Specialists. Sing Non-warping door blanks are available in any type, style, shape, exterior skin and/or composite configuration.

Insulated Door

Rumney Guggenheim Gallery Williamsburgh Savings BankInsulated doors offer enhanced separation between two areas separated by an opening, doorway or egress point. Sing Core insulation starts at R3.5 per inch and goes up from there, based on architectural specifications. Insulated door are of primary interest to architects, designers and engineers seeking soundproof door, hurricane doors* or other weatherproof door where an insulated door is specified.

Security Doors

Sing Core is of primary importance in security doors of substantial size. Large security doors are difficult to manage normally due to weight; this problem can be solved with the Sing solution. A security door can be used in a variety of circumstances and applications including impact doors, and bulletproof doors.

Television-studio-moveable-sound-walls-sound-proofUsing Sing Core™ inside, impact resistant doors don’t have to be heavy weight, which causes unnecessary stress and strain on both the hardware and structure, while delivering all the security desired including increased privacy due to innate door insulation.

Specialty Doors

Sometimes a custom door manufacturer, millwork or door manufacturer faces a job that requires doors with unique attributes to accommodate a particular usage following installation.

Specialty doors may need particular characteristics to meet the requirements of the end user. Architects, designers and engineers can use Eco-friendly Sing Core™ inside to have greater control over:

Sound deadening
Impact resistance
Any size
Any style
Any performance
Any exterior surface


Get the door that you want, when you want, how you want it to perform

Patented Sing Core is the most high precision door core material producing the highest performance doors in any type of door that are elegant and possess superior functionality.


sliding doors
pivot door
revolving doors
automatic doors
portable partitions
operable walls
hinged doors
balanced doors
garage doors
barn door
security doors
industrial doors
hangar doors
acoustic doors
warehouse doors
vestibule door
religious institutions
retail centers

Contact Sing Core

Contact the Non-warp True Flat Specialists to see if getting Sing Core inside your door just makes perfect sense.

*Customer will need to perform lab tests to certify hurricane rating for local code compliance.