It's What's Inside That Counts: 3 Different Types of Popular Hollow Steel Door Cores

Hollow steel doors are an industry favorite because of their durability, versatility and strength. When properly maintained and installed, hollow steel doors can often last over 30 years or longer without requiring large repairs. The outer steel is a strong barrier preventing intruders from gaining access inside, but what really counts is what's inside.

The type of material that the core is made from makes a world of a difference. Hollow steel doors can be made from different cores—all with unique properties. This article will take a quick look at three popular options.

The Honeycomb Core

The honeycomb core is the most basic type of core you can get with hollow steel doors. It was extremely popular because of its high strength-to-weight ratio, high shear strength and impact resistance abilities. The honeycomb design also acts as a noise-reducing insulation and will easily filter out external noise.

The honeycomb core is made from heavy kraft paper shaped into hexagonal cells and phenolic resin. The phenolic resin does a great job at preventing mildew and insect infestations. The hexagonal cells and structure form hundreds of small I-beams with the door. Although this type of core is incredibly effective and durable, the honeycomb core can be difficult to manufacture. The core must be sanded down to the right thickness for optimal performance.

The Polystyrene Core

The polystyrene core looks a lot less unique than the honeycomb core because it is essentially just a slab of polystyrene. Polystyrene has become increasing popular as the primary type of core chosen for hollow steel doors because it is environmentally friendly, light and an excellent insulator. Polystyrene cores are technically not as sound and strong as honeycomb cores; however, they are much better insulators with an insulating value of 6.9R and will improve the energy efficiency of the building by preventing heat loss or temporal exchanges.

In comparison to honeycomb cores, polystyrene cores are also a lot easier to install and manufacture. As a result, they are also often cheaper than the honeycomb cores.

The Steel Stiffened Core

Hollow steel doors leading outdoors are most commonly made with a steel stiffened core due to the incredible strength and stability it can offer. You won't be able to kick this door down—that's for sure. This type of core is filled with fiberglass insulation to prevent heat from being exchanged. The type of steel used, such as gauge and thickness, will vary by manufacturer. Depending on your need for security and safety, your requirements for the thickness and gauge may change. The pieces of steel are then welded together at the top and bottom to the door with the remaining spaces filled with the fiberglass insulation.

Hollow steel doors with a steel stiffened core are generally the most stable and secure; however, they are also quite a bit more expensive in comparison to the other options thanks to the difficulty involved in installing the core and the cost of the materials. Steel stiffened cores have the ability to perform under a wider range of stress conditions, but are also considerably heavier.

Many property owners and building owners are opting for hollow steel doors rather than wooden slabs and other alternatives due to the increase in strength and durability witnessed. Hollow steel doors are also fire-resistant and can act as a temporary barrier in preventing fire from getting from one room to another. When shopping for hollow steel doors, keep in mind that beauty is only skin deep. The quality of the door and what it can offer you is largely dependent on the type of core that is inside.