A slab door is a door supplied without any factory cuts or hardware preparations. Instead, it consists of a single slab of wood or metal with square, uniform edges. These slab doors, or blanks, provide the most flexibility to buyers in terms of how and where the door can be installed. Installers simply have to drill, cut, and bevel the door based on the requirements of the project.
Standard doors are sold in three formats. The pre-hung door is the most common, and features a door already hung on the hinges and attached to a frame. Other doors are not pre-hung, but are pre-prepped at the factory to accommodate hinges and other hardware. These doors require the least amount of skill from the installer, but provide very little flexibility in terms of where the door can be used. Slab doors represent the most flexible option, but also require the most skill from installers.
To use a slab door, installers must carefully measure the frame or opening where the door will be installed. This allows them to cut the door to the correct size, including undercutting the door to allow it to swing freely without catching the floor. The edges of the door must be recessed to receive hinges, and also beveled, or cut at an angle to maximize operation. Cuts or openings must be created for all additional hardware, including locks, stops, and closers. Standard and pre-hung doors already come pre-equipped with all of these features.
Typically, a slab door represents the most economical option for homeowners looking to add or replace a door. They are also the best option for installing a door in unique openings where a standard door doesn't fit properly. These doors also provide the most versatility, and can be cut down, beveled, and prepped in the field as needed.
One potential drawback to using a slab door is the difficulty required to properly prep the door in the field. While most skilled carpenters can prep a wooden door fairly easily, metal, or fiberglass slabs require special tools and a very high level of skill. Slab doors are also difficult to install, particularly in exterior openings where moisture resistance is a primary concern. Finally, doors that are designed to resist the spread of fire or smoke may not be cut or prepped in the field, and must be fully prepped at a certified factory prior to installation.