About French Doors

People have been building French doors for years, but now, thanks to inventor Peter Sing’s patented and patent-pending warp-free French door technology the biggest and best door companies, millworks, and high end custom French door manufacturers know the best way to build a French door is with Sing’s core inside.

Big doors mean big glass and a big frame means a very heavy door which is difficult to install, operate and can be expensive to maintain over time, but with Sing Core hosting your glass you can reduce the weight of your French door tremendously, without having to sacrifice the strength of steel.

Inventor Peter Sing’s patented and patent pending French door technologies enable the largest and most prestigious door companies, high end millworks, and custom French door artisans to create sustainable Eco-friendly French doors which are lightweight, high strength (Sing’s core is stronger than steel pound for pound), and come backed by Sing’s unprecedented 

50-Year Warp-free Guarantee

Sing Core is the strongest way to behold glass in any size opening, in you French door which is easier to install and open and close for years of customer satisfaction without risk of warping, bending, twisting, cupping, or failing in any other way, including lamination, guaranteed.

Try Sing Core inside your French doors and you will agree with Sing’s most prestigious clientele, who depend on his True Flat Team to deliver the most high precision, high performance French doors of any size, made of nearly any material,

“Sing Core is the only way to do it.”

French doors made with Sing core panels are exquisite elegance with high function and performance in the most elite applications for homes and patios. When transitioning from one environment to another, Sing panel French doors offer a spectacular gateway that offers protection from the elements while providing a beautiful panoramic view of the landscape.

Walnut Sliding French Doors

French doors made with Sing panels come complete with complimentary light opening cutouts allowing the beauty and luminescence of the outdoors to visit the interior of your home.  Whether single or multiple French doors,  Sing panel French doors provide an impressive focal point to your classic home, office, restaurant or other commercial application.

French doors made with Sing panels are available in any size (up to 50 feet) or shape per your specification and can be used in sliding door configurations.  You may choose from our stock panels or order custom-sized panels.  Sing Core specializes in large oversize doors.

Many educated homeowners demand that their trade professionals (architects, millworks, contractors, etc.) use Sing Core products in their home projects. See: Standard French Door Specs

French Door Technology

Sing French door panels are a new technology which consists of our patented Sing core sandwiched with two skins and a solid wood frame. Compare our panels with the conventional stile and rail door method made up of dozens of loose components fitted together.

With Sing French door panels you get:

  1. Stronger corners and joints, especially between the glass and the wood frame;
  2. Any design you can imagine by adding molding and trim;
  3. Any size width and length or shape;
  4. Complimentary lite opening cutouts per your design; and,
  5. More affordable because they need less labor to build than stile and rail doors.

The Sing Core Difference

Due to the unique advantages of our patented Sing core, which is the heart of our French door panels, Sing panel French doors are in demand.  Sing cores are imbued with qualities that are far superior when compared to other traditional or commercially-available French door panels.  Our patented new door technology incorporates our space-age core that is extremely lightweight, yet pound-for-pound stronger than steel at a fraction of the cost.



Huge 14 Foot French Door Easily Lifted by One Guy

These 16′ french doors can make any entry a fairy tale style entry.

Sing Core French Doors are much more lightweight than French Doors manufactured by other door companies due to the unique properties of the patented Sing Core used in the design of these doors.


In terms of strength, Sing Core is pound-for-pound stronger than steel and have compression strength rated at 660 PSI.  Our solid Sing core door panels are designed to be  warp-free; twist and rot resistant; can be extremely weather-tight; and are much stronger than traditional stile and rail configurations that breakdown and weaken overtime, or fail at the joints under extreme conditions.


French doors made with Sing panels are pre-insulated and allow sunlight in for natural solar advantages and energy efficiency.  They also allow you to enjoy enhanced peace and quiet between varying environments due to the superior sound-deadening qualities of Sing Core French Doors.


French doors made with Sing panels are manufactured using natural wood and recycled foam components, and our patented bonding materials (adhesives) are formaldehyde-free.  The construction process uses less energy, manpower and produces little or no waste.  Due to Sing panel lightweight properties shipping, transportation and installation costs are reduced.


Though used in high-end designs, French doors made with Sing panels are competitively priced, and even though they are handcrafted in the USA, can still compete with inexpensive imports.

Click here for more information on doors made with Sing panels

How We Build French Doors (The Best Method – Sing Torsion Box Panel Method)

The easiest way to build the best doors.

Step 1 – Apply Glue to the Skin

Step 2 – Build Solid Wood Frame

Step 3 – Install the patented Sing honeycomb torsion box core & press on the skins.

Step 4 (optional) – Cut hole for window and prepare window trim.

Step 5 (optional) – Install glass and finish the door to desired look and function.

Step 6 – Install the door onto jam.

Method 2 – How We Build Our Doors (The Second Best Method – Stile Rail)

On the left are patented Sing honeycomb stile and rail. On the right is veneer (walnut) ready for gluing onto the patented Sing honeycomb stile and rail.

Apply glue to our patented Sing honeycomb stile and rail.

Press veneer to patented Sing honeycomb stile and rail. Most honeycomb panels cannot handle the high pressure and temperatures of the hot press, Sing honeycomb can.

Stile and Rail after the veneer has been pressed on.

See how straight the patented Sing honeycomb stile and rail are, yet they are still incredibly strong and lightweight.

Drill holes to accept dowels.

Doweled and glued.

Router out the end if hardware is to be installed

Stained and ready for glass and installation.

Pictures courtesy of Robert Shaw – www.robertshawmfg.com

Doors 8′ – 7″ tall

French Door Gallery