Need Help? 866-232-5673 M-F 9AM-3PM CST
Text Us Or Send Us Photos 210-275-8966
A common misconception is that hollow metal doors are empty inside. In reality, commercial hollow metal doors are insulated steel doorsbuilt from multiple components that work together to provide durability, security, fire resistance, and long service life.
This guide explains what hollow metal doors are actually made of and why those materials matter when selecting a door for a commercial building.
The exterior structure of a hollow metal door is formed from cold rolled steel sheets. These steel skins create a rigid shell that surrounds the internal core.
Steel thickness (gauge) varies by application:
Lower gauge numbers indicate thicker steel and increased resistance to abuse.
Inside the steel shell is an insulated core. The core adds strength, thermal performance, sound control, and (when applicable) fire resistance.
The two most common core types used in hollow metal doors are honeycomband polystyrene.
To compare core performance, it helps to understand two measurements:
Honeycomb core doors get their name from the internal cardboard structure, which resembles a honeycomb pattern. This core provides basic rigidity at a lower cost.
Honeycomb core doors are commonly used for interior commercial applicationswhere fire rating and higher insulation values are not required.
Polystyrene is a rigid foam insulation that provides improved thermal performance and strength compared to honeycomb cores.
Because of its better insulation and moisture resistance, polystyrene core doors are suitable for both interior and exterior applications.
Polystyrene core doors have a lower U-value and a higher R-value, meaning they resist heat transfer more effectively than honeycomb core doors.
This does not mean honeycomb doors are “bad.” They are a cost-effective option when budget is the primary concern and the door is used in a non-exterior, non-fire-rated application.
For exterior doors, higher-traffic areas, or applications where insulation matters,polystyrene core doors are typically the better choice.
Beyond the steel skins and core, high-quality hollow metal doors include internal reinforcements that dramatically affect durability and long-term performance.
Quality hollow metal doors include a 12 gauge steel reinforcement platewhere a door closer is mounted. This reinforcement provides the strength needed to support commercial hydraulic door closers.
Doors without closer reinforcement often experience:
The top and bottom of the door are critical structural points. High-quality hollow metal doors use 16 gauge top and bottom capsto maintain door rigidity and prevent warping or denting.
Lower-cost doors often omit these reinforcements, which can lead to bending and long-term performance issues.
Hinge reinforcements are another critical component. Quality hollow metal doors use heavy-gauge hinge reinforcement to properly support the door weight.
Doors without adequate hinge reinforcement often suffer from:
Hollow metal doors are frequently specified for security. Proper lock reinforcement helps prevent forced entry and damage.
Doors with reinforced lock preps and optional latch guards provide significantly better resistance to prying and vandalism, reducing long-term repair and replacement costs.
Hollow metal doors are made from much more than just steel sheets. The combination of steel skins, insulated cores, and internal reinforcements determines how the door performs over time.
Understanding what goes into a hollow metal door helps ensure you select the right product for your application.
To explore high-quality commercial steel doors or configure a custom opening, visit ourCommercial Hollow Metal Doorsor use ourBuild Your Door Quote Tool.
Whether you need a quotation or just have a question about a product. Reach out to us today by calling 866-232-5673 or text us questions and photos at 210-275-8966, and one of friendly specialists will be happy to help!
