Doors 101
When you’re ordering commercial double doors or exterior steel double doors, the last thing you want is a damaged shipment slowing down your project. At CDF Distributors, we understand that these doors aren’t just pieces of steel—they’re investments in safety, security, and smooth daily operations. That’s especially true for fire rated double doors, where performance matters from day one. That’s why we take extra care every step of the way, from production to shipping.
Fast-Track Production with Care Built In
Every door that leaves our facility goes through a carefully designed process. Here is what sets our doors apart.
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Precision Manufacturing: Doors are built to spec with tight tolerances, ensuring they fit perfectly on arrival.
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Quality Checks: Each door is inspected for alignment, finish, and hardware placement—so there’s no last-minute surprises on site.
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Protective Packaging: Heavy-duty wrapping, custom crating, and careful pallet placement mean your commercial double doors
Choosing the correct door handing, also called door swing, is a critical part of specifying fire rated double doors. Door handing affects how the doors operate, how hardware is applied, and whether the opening meets fire and life safety requirements. For commercial double doors, including exterior steel double doors and interior fire-rated openings, understanding handing helps avoid installation errors, inspection failures, and costly rework.
Whether you are specifying a double door fire rated opening for a corridor, stairwell, or exterior wall, door handing must work in coordination with fire-rated hardware. Below is a clear breakdown of the most common handing options used for a double fire door and how each functions.
Types of Door Handing for Fire Rated Double Doors
Left-Hand Active
In a left-hand active configuration, the left leaf is the primary operating door. It contains the latch and opens first during normal use. The right leaf is typically the inactive door secured with vertical
When it comes to schools, even small door issues can turn into big problems fast. From daily disruptions to serious safety concerns, school doors play a major role in how smoothly a building operates. Every classroom door and set of school entrance doors must work reliably to support student movement, security, and compliance.
In busy learning environments, a damaged or poorly functioning school classroom door can slow down hall traffic, create safety risks, and lead to costly repairs if problems are ignored. Understanding the most common issues with doors for schools, and knowing how to fix them, helps administrators and facility managers keep buildings safe, efficient, and ready for everyday use.
Door Misalignment and Sagging
One of the most common problems with a classroom door is misalignment. Over time, frequent use can cause doors to sag, drag on the floor, or fail to close and latch properly. In high-traffic school doors, this is often caused by worn hinges, loose fasteners, or
Commercial doors can be made with a variety of materials, and door systems are really a combination of parts, doors, frames, and hardware all working together. The metal door frame is one of the most important of those parts, even if it doesn’t always get the spotlight. Choosing the right frame impacts how smoothly your door installs, how long it lasts, and how well it performs over time.
At CDF Distributors, we make frame selection simple by offering purpose-built commercial door frames that are matched to the door type and building conditions. From knockdown door frames to fully welded assemblies, storefront systems, and pre-hung metal building doors, each frame type is designed to do a specific job and do it well.
Hollow Metal & Wood Door Frames
For commercial applications, CDF exclusively offers steel door frame solutions. Our frames are built for strength, longevity, and performance in demanding environments like offices, schools, healthcare facilities,
If you’re searching for where to buy commercial steel doors, chances are you need something durable, secure, and ready to ship without a lot of back-and-forth.
You can buy commercial steel doors online from CDF Distributors, where you can compare options and get instant quotes in minutes—without delays or complicated ordering.
Your Options for Buying Commercial Steel Doors
When it comes to sourcing commercial steel doors, most buyers fall into one of these routes:
1. Local Suppliers
Buying locally can be helpful if you want to see products in person. But inventory is often limited, and getting custom sizes or configurations can take time.
2. Big Box Retailers
These stores may carry basic steel exterior doors, but options for commercial projects—like reinforced frames or double door setups—are usually limited.
3. Buying Online (The Easiest Option)
Online suppliers give you access to a wider range of products, better pricing, and faster comparisons—especially for commercial-grade
How often do you think about the door you walk through every day? Probably not often, but when you’re responsible for sourcing commercial steel doors, suddenly every detail matters. From fire ratings and lead times to hardware compatibility and shipping schedules, the door you choose can make or break a project.
That’s where CDF Distributors stands apart. While big box stores may feel convenient at first glance, contractors, architects, and facility managers across the country are discovering that working with a specialized door distributor leads to better outcomes, especially when it comes to commercial steel double doors, steel exterior doors, and fire rated metal doors.
Let’s take a closer look at why CDF Distributors is the better choice for commercial metal doors.
CDF Distributors vs. Big Box Stores: A Clear Difference
Door Experts vs. Generalized Sales Staff
At big box stores, you’re often working with well-meaning associates
CDF Distributors provides three ways to order commercial door assemblies: online through ProBuilder, by phone at (855) 769-9895, or by email at sales@cdfdoors.com. ProBuilder is CDF’s proprietary online configuration tool and the fastest way to build a quote, select compatible components, and place an order. This FAQ covers the ordering and quoting process for hollow metal doors, hollow metal frames, wood doors, commercial hardware, and storefront systems available through CDF.
CDF ships from its Nashville, Tennessee headquarters and serves general contractors, subcontractors, facility managers, and building owners across the United States. Approximately 70 percent of CDF’s customer base consists of general contractors working on commercial construction and renovation projects.
About This Guide
This FAQ is published by CDF Distributors and reflects CDF’s standard ordering, quoting, and account procedures. The information applies to all product categories available through CDF, including
The rough opening for a commercial door frame depends on the frame type. For drywall wrap-around frames, add 2 inches to the nominal door width and 1 inch to the nominal door height. For masonry frames, add 4-1/4 inches to the nominal door width and 2-1/8 inches to the nominal door height. These formulas account for the jamb and header material that occupies space within the opening. Getting the rough opening correct is a critical first step in ordering the right size door and frame assembly.
CDF Distributors’ ProBuilder tool at cdfdistributors.com calculates rough openings automatically for every frame configuration, displaying both nominal and exact dimensions on every quote. For assistance, call (855) 769-9895 or email sales@cdfdoors.com.
Rough Opening Formulas
All door sizes referenced in rough opening calculations are nominal sizes, not exact sizes. A nominal 3’0” x 7’0” door is referenced as 36” x 84” in calculations. The rough opening formula varies by frame type because each type
Commercial storefront door systems are available in narrow stile, medium stile, and wide stile configurations, each designed for different traffic levels and glass area requirements. Glass options for storefront doors include tempered, laminated, insulated, and low e. This reference guide covers storefront door types, and glass specifications and the factors that determine which system to specify for a commercial project.
CDF Distributors supplies storefront door assemblies from its Nashville, Tennessee headquarters. You can configure and order complete door assemblies online using CDF’s ProBuilder tool at cdfdistributors.com. For assistance selecting the correct glass type or storefront configuration for your project, call (855) 769-9895 or email sales@cdfdoors.com.
About This Guide
This reference guide is published by CDF Distributors, a commercial door and hardware supplier headquartered in Nashville, Tennessee. CDF fabricates hollow metal door and frame assemblies in-house and supplies
Wall thickness determines which hollow metal door frame fits your opening. To measure wall thickness, place a tape measure against the outside face of the finished wall on one side and measure straight through the opening to the outside face of the finished wall on the opposite side. This measurement, taken from sheetrock face to sheetrock face, must match the throat size of the frame you order. An incorrect measurement results in a frame that is either too loose or too tight to install properly.
CDF Distributors’ ProBuilder tool at cdfdistributors.com allows you to select the exact wall thickness during frame configuration, ensuring the throat size matches your wall assembly. For assistance determining the correct frame depth for your project, call (855) 769-9895 or email sales@cdfdoors.com.
What Is Wall Thickness and Why Does It Matter?
Wall thickness is the total distance measured from the outside face of the finished wall material on one side of a partition to the outside face of the