5 Types Of Cores Found In Wood Doors

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When it comes to choosing wood doors for your business, it's easy to get caught up on the appearance and the door and ignore what's inside. What you may be surprised to learn however, is that the attractive wood finish you see on a door is extremely thin; the bulk of the door's weight and strength comes from its core. In modern commercial doors, this core generally consists of one of five basic materials. Understanding the differences between these cores can help you find doors that suit both your budget and performance needs.

Paper or Cardboard

Hollow core doors are the most affordable and lightweight commercial doors on the market. The inside is made up on heavy paper or cardboard formed into a network of honeycomb shapes; these honeycombs may be soaked in resin or some other binder to increase strength and durability, or simply left in their natural state. Choose hollow core doors only on openings with relatively little traffic, and minimal exposure to potential damage.

Wood Waste Products

The majority of commercial wood doors used in offices contain particle cores. These cores consist of sawdust or similar wood waste products pressed together using resin to form a strong, solid layer – similar to the sheets of particleboard you see at hardware stores. These doors offer good holding power for screws, making it easy to attach hardware so that it will last with minimal maintenance.

Wooden Blocks

Stave cores are made up of many small wooden blocks arranged in rows and glued together to form one solid piece. They give the door tremendous weight and strength, and also provide good holding power for screws. While these doors work well in situations where a bit of extra strength is needed, keep in mind that it's possible for the blocks -- or gaps between the blocks – to telegraph through the surface of the door, leaving ugly indentions or patterns.


Use mineral cores if you need a door with fire resistance, such as those installed in fire-rated walls or openings. Mineral cores are generally made from gypsum or related substances, which can slow the spread of heat and flames during a fire to allow for safe egress, and possibly protect your property until firefighters arrive. Keep in mind that mineral cores come with different ratings based on how long they can slow the spread of fire, so be sure to choose one appropriate for each specific opening.


If you're looking to green your business, agri-fiber cores can help make doors more eco-friendly. Instead of wood, these doors use cores made from pressed plant fibers, such as wheat or rice. These plants are rapidly renewable, and will regenerate themselves much faster than a tree to reduce your impact on the Earth.