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#1 Best Seller: Oversize Doors

80% of the doors we sell are true flat large oversize doors (over 4 ft. x 8 ft.), though we do specialize in 5% regular-sized doors.

#2 Best Seller: Sliding Door

Custom Lite Openings for Glass – No Extra Charge

The door is a moving structure used to block access, visibility and noise between two otherwise connected areas. The door as we know it is moving to the next level of high-performance, safety and security thanks to patented Sing Core.

This new door revolution is introducing a new evolution in door technology that delivers an insulated door that is true flat, lightweight, stronger than steel and Eco-friendly. Sing Core doors are the high-end solution used by the best millworks when it’s important to deliver the best door.

Enjoy the safety and security of a door that cannot be easily breached and is much safer for finger and limb injuries due to the lighter weight than conventional doors. Sing Core doors are available in any door configuration and/or size and available to all door manufacturers.

torsion box, sandwich panel, honeycomb panel, lightweight panelTypes of Doors

Sing Door Panels

Photo Galleries

How to Build

Patented Sing Core: We put a torsion box in the SIP panel to make it better. The other names for our panels include sandwich panel, honeycomb panel and lightweight panel.

Door Industry

Best Door in Manhattan

Manhattan Penthouse brings Sing Core Door to new heights.


Craned up to Manhattan highrise.
Click to enlarge


No place is too far.

This custom made trapezoid door traveled over 2,921 miles from coast to coast, now on final leg of its journey to its new home in upscale Manhattan apartment. We specialize in custom sizes, shapes and thickness to fit our customer’s needs, we offer the best guarantee in the door business. Best Custom Oversize Sliding Door in Manhattan

Door Closed Door Open
Door Open
Door Closed

Sing Punch-Proof Doors

SINGCORE-The new generation of door making it impossible to punch through and destroy.

As low as $50 a door for a door that will last a lifetime.

torsion box, sandwich panel, honeycomb panel, lightweight panel
Punch proof Sing Core door.
Typical paper core door. (click to see more)


What door companies do not want you to know.

Today, the most common doors found in private residences contain a paper core. These doors are flimsy and are easily punctured, even when slightly impacted. Owners of these doors find themselves spending time and money on repairs, replacements, and installations that would not have been an issue had they purchased a door from Singcore. Singcore doors do not cost much more than paper-core doors, yet they have been tested to be at least 49 times stronger.

Door Security

How secure are your doors? With our patented core, you can rest assured that our torsion box technology will stand up to harsh treatment and all weather conditions. Our doors have been thoroughly tested and have been proven to withstand the impact of a sledgehammer. There is no comparison between the stability, structure, and strength of Sing Core doors versus paper-core doors. This is a Sing Overhead Garage Door Panel compared next to a typical steel overhead garage door panel. Same size and thickness but as you can see the steel panel buckles with only a few pounds put on it while the Sing Panel holds almost all of Inventor Peter Sings weight without any problem.

Stronger than Steel,

Lighter than Wood

Doors do not have to be made out of steel to be rigid and strong. Sing Core doors are stronger and lighter, than steel and vinyl doors. Standard steel overhead garage doors are made of steel so thin that a golf ball can dent it. This is not the case with Sing Core doors. We offer higher quality doors at prices competitive with steel doors with quality superior to wooden doors.

Sing Core doors are more stable, provide better insulation, and are far lighter than solid wood doors. The torsion-box core holds the Sing Core door flat, ensuring that that the panel will not warp and sag like ordinary wood.

Patented Sing Door Methods

Sing Core doors are versatile and customizable. Every order is custom designed with the client’s project in mind. Each door is constructed using methods that specifically cater to our customers’ individual needs. We construct our doors using the following methods: pole barn grade, paint grade, wood grain grade, and plank grade.

Click Here to Learn How to Build a Sing Door


How to Buy

Sing Door Panels are easy to order (link). You may select panels of standard dimensions from our inventory, or you may order custom sizes and shapes. Please submit a Work Order by fax or email, and we will get back to you with a free quote within one business day. You only need to submit the length, width, thickness and quantity. Even if you have an unorthodox idea or a tight budget, give us a call. Our representatives will help devise an alternative solution tailored to your needs. Sing Core allows you to design your own doors. Just add trim, paint, and hardware*. Exceptional pricing is available to distributors, manufacturers, and retailers . Doors Pamphlet For Distributors person-carriage-door-garage-sing-core

Door Panel Pricing

Simple Price/Order Process

Simple Price/Order Process

Sing Door Assembly  Sing Door Strength Demo

Large Oversized Doors

See the Sing Best Door definition Sing Core specializes in custom 1-off high-end large oversized doors, sliding doors and aluminum doors. Why? Because no other door manufacturers does huge eco-friendly doors better. The Sing Core Door manufacturing plant is set up especially to make doors that are up to 50 feet tall, yet true flat, lightweight and stronger than steel. Sliding-barn-doors-wine-brewery-lightweight-strength-eco-friendly-true-flat Huge doors present a variety of complications for designers and installers. Due to structural changes in the materials and changes in the physical environment. A door that appears to be a perfect fit at the time of installation, most likely will be a huge disappointment over time. This causes extraneous maintenance fees, loss of energy, and lack of long life requiring early replacement.

True Flat – Guaranteed
Sing Core is the only door manufacturer that can create eco-friendly doors that can be guaranteed true flat regardless of the size, and will not warp, twist or experience extreme deflection under stress. And, thanks to the lightweight properties in comparison to other solid materials available, Sing Core oversized doors though large in size, are lightweight, causing less strain on the structure and hardware. Sing Core doors are available in any height, any width, any thickness. Energy saving doors are becoming more important especially when considering doors of large size. Sing Core large oversize doors are extremely energy efficient due to built-in insulation that adds both energy saving and sound deadening properties. 3-sliding-exterior-doorsSing Core large doors are not only Eco-friendly, lightweight and stronger than steel, they are extremely affordable when compared to other lightweight but strong materials. The best-known, oldest, most reliable, high-end millworks in the United States depend on Sing Core to deliver the goods for them when it comes to large, oversize doors. Why? Because Sing Core large doors are the only oversized doors that can outperform any other door in terms of long-lasting satisfaction and guaranteed true flat. Just let us know your expectations and based on our expertise, we will be able to provide you with a solution that we can guarantee. Challenges of door manufacturing are based on three factors: 1. The skin (surface material) 2. The thickness 3. Door size Based on years of experience, we know how to manipulate those numbers to your best advantage to make certain that you get the results you desire. If you’re considering an immense large interior or exterior door, you should consider a Sing Core large oversize door that comes with a full 10-year structural warranty. Some of our design solutions include very large doors, like large French doors, large carriage doors, large closet doors, large cabinet doors, large guillotine doors and large front doors and in most cases to guarantee true flatness aluminum plays a part in the composite design. Sing Core oversized entry doors, oversized French doors, oversized front door, oversized interior doors, large glass doors, large patio doors and large entry doors by far exceed the requirements of any other doors available on the market today. When it comes to large exterior doors, large pocket door, large interior doors, large glass sliding doors, large garage doors or large wooden doors no other door manufacturers can deliver superior results, like Sing Core. Whether you’re considering a large sliding glass door, large wood doors, large sliding doors exterior, large shop doors, large opening doors or large pivot doors, Sing Core is your one-stop solution for your oversize door, guaranteed. Lightweight insulated door core 15' length

Sliding Door

Sing Core is the new way to design your door

Solid like a rock, light like feather so you don’t smash your finger.

One finger easy open lightweight sliding doors by Sing Core true flatIf your sliding doors are large, you probably have to deal with the issues of added weight that can be problematic. Lightweight Sing Core’s torsion-box substrate is the answer to dealing with the issues of weight of large sliding doors yet adds high structural integrity, and helps to prevent injury to the end-user(s). Wood sliding patio doors, sliding glass doors, and even the most high-fashion vinyl sliding patio door can be expertly engineered with patented Sing Core technology. Strengthening outdoor sliding doors and reducing the weight helps to protect and reduce maintenance to expensive sliding door hardware as well as added stress and strain on the structure. When considering your sliding door ideas, think about the size, the weight and the structural integrity of your sliding door system over time.


The Sing Core sliding door offers so much more than luxury, but also increases safety and security of the homeowner’s family, the contractors and workers, as traditional overweight sliding doors have been known to be unsafe and can cause injuries threatening life and limb. Reduce liability of your contractors and commercial clients by reducing on-the-job injuries and help to protect the lives of your clients and their families in residential settings. Even the best health insurance cannot replace a finger that has been crushed by a heavy sliding door.


When it comes to sliding doors for walk in closets, most people don’t recognize the importance of remaining true flat inside the pocket door frame. Whether you’re looking for a pocketed door system, wall-mounted system, hanging or floor track system, you can experience the superior performance of your single French door, fiberglass French door or exterior French door because you’ve been introduced to the best sliding French doors for sale on the market today. Exterior sliding barn doors can be beautiful following installation, but after time, problems develop due to door failure. They tend to expand and contract due to weather exposure causing them to warp, twist, and crack, compromising the overall performance of your sliding barn door system. Even a 1/4″ deflection can compromise an otherwise aesthetically pleasing completed project. Sing Core’s true flat guarantee is why high-end millworks and designers seek out Sing Core for extreme weather and temperature-controlled environments. For the do it yourselfer, DIY sliding closet doors can also be a challenge, and Sing Core can help to bridge the gap between the solo sliding door project. Sliding closet doors are gaining popularity amongst discerning builders and designers, while wooden sliding closet doors are extremely attractive, infusing Sing Core technology can save your interior sliding doors from warping, twisting and/or cracking, so that you can enjoy the elegance and functionality of your sliding door for lifetimes with little or no maintenance.

No company excels in building sliding doors that are much larger than the standard 8 foot sliding patio door. Sing Core specializes in building extreme oversize, large sliding doors that are true flat and guaranteed. When you’re designing a double sliding door system, the true flat advantages of Sing Core helps to maintain the structural integrity, keeps the sliding of the doors from interfering with the perfect functionality and long-term efficiency. And increase in interior design trends, like the wall mounted sliding door, Sing Core is the sliding doors company that can get your from here to there whether you are looking for a sliding door for bathroom, sliding barn door kits, sliding door dividers. Sing Core is your preferred resource if you want to avoid cheap sliding patio doors. Sliding fire doors are gaining popularity in the Sing Core sliding door lineup. Regardless of the wide variety of types of sliding doors, Sing Core offers the elegance and excellence in barn door sliding door, sliding office doors, and exotic sliding doors, like, Chinese sliding doors, sliding French doors exterior, Shoji screen sliding doors and/or Japanese style sliding doors. Barn door interior sliding doors come in a variety of materials that are virtually unlimited to match your aesthetic tastes including, aluminum patio sliding doors. Sing Core makes the best real sliding door that solves the challenges that face architects and designers around the world for the best results, guaranteed.

True Flat Oversize Doors

Sing Core 37 foot tall true flat doors

Sing Core 37 foot tall true flat doors

We guarantee that we are the only company in the world that can deliver true flat oversize doors that meet your expectations, if you desire a true flat solution, especially in the large, oversize door.

One of the biggest challenges we see from designers and developers is that of the oversize door. Sure, anyone could make an oversize door, but can you make one that is true flat, maintaining structural integrity over long spans? That’s where Sing Core shines.

3 Types of Oversize Doors

There are three types of oversize door solutions, and in terms of meeting or exceeding the needs of the most high-end clients in the world. Our specialty is solving the problems associated with large oversize doors, while maintaining true flatness under extreme circumstances is unheard of, Sing Core helps us achieve the results that no one else can and remain lightweight and Eco-friendly, too. 1. Large Oversize Wood Door The large oversize wood door has been a challenge for centuries because regardless of your expectations or requirements, the very nature of wood itself will provide additional challenges for both designer and the design. Not until the invention of Sing Core has there been a perfect solution for the issues associated with large oversize wood doors. See more information on Large Oversize Wood Doors. 2. Large Oversize Aluminum Door For more extreme oversize solutions the Sing Aluminum Door is the better solution, especially when doors are expected to remain true flat under varying conditions. Aluminum has certain attributes that help us reach and exceed the requirements of the most demanding high-end clients. See more information on Large Oversize Aluminum Doors. 3. Large Oversize Wood/Aluminum Composite The best solution for battling the issue of oversize without compromising the look, feel, beauty and elegance of solid wood is to call in the specialists at Sing Core to help design the perfect solution to your strictest concerns and requirements. See more information on Large Oversize Wood/Aluminum Composite. 4. Large Oversize FRP Composite Door If your large oversize door will be facing extreme weather conditions, temperature variations, or some other kind of added stress that might be above what would be considered normal exposure. Every day someone finds the Sing Core solution. For instance, when O.B. Williams needs a hundred oversize doors, that are guaranteed flat, who do they turn to? They call Sing Core to get the job done. Plus, you have all the advantages of patented Sing Core, with any appearance that you like i.e., aluminum or exotic wood grain finish… In a hurry? No problem. Sing Core can build your true-flat oversize doors for you in less than 3 days, even though our normal turnaround is 2 to 6 weeks. Sing Core’s got your back. We make you look good. When your client demands only the best… You can confidently use Sing Core as your resource, because when it comes to oversize, true flat, nothing else even comes close. Any look you desire… 13 foot lightweight panel strength peter sing coreOversize Sing Core doors can achieve any exterior surface your customer desires, including (but not limited to) any wood species you customer desires, concrete, fiberglass, aluminum, stainless steel, fire-resistant Magnesium Oxide (MgO) Board, bullet-proof Kevlar, etc… How do we do it? Oversize and true flat is a challenge that we take on every day. We know the perfect combination of patented sing core and aluminum, to maintain light weight, superior strength and true flat construction. This is how we build sustainable, high-end, true flat doors consistently and guaranteed for ten years.