Small details make a big difference in door hardware

A door is deemed sustainable when the specified hardware lasts for years. Images courtesy Legacy MFG
A door is deemed sustainable when the specified hardware lasts for years.
Images courtesy Legacy MFG

Rubber grip

While a rubber adhesive may be appropriate for a low-traffic doorway, it is generally not recommended for commercial applications. It is made up of a blend of synthetic rubbers and chemical compounds.

Aluminum composite filler

This contains aluminum oxide and silicone carbide and is suitable for applications with heavy commercial traffic in supply rooms, manufacturing buildings, schools, cafeteria, automobile dealers, hospitals, and industrial facilities.

Photoluminescent epoxy abrasive

The most common use of a photoluminescent adhesive is with fire door assemblies as well as common indoor applications on staircases. It includes a photoluminescent tread for visibility.


Thermal break thresholds are used when there is an opposition in temperature from one side of an opening to the other. These are designed to inhibit the transmission of thermal energy through more conductive materials. This type of threshold may be specified when conserving energy in very hot or cold environments is desired.

Rabbeted thresholds include a built-in stop, designed to allow the door to close against the seal and inhibit airflow.

In many cases, the end-user does not prefer the ‘look’ or encumbrance of a threshold. In these cases, a cycle-tested automatic door bottom is recommended. The different variations and options available in thresholds can provide specifiers with flexibility to properly accommodate a variety of sill conditions.

Automatic door bottoms

Automatic door bottoms provide protection from fire, smoke, noise, and other threats to the life safety and comfort of building occupants. These require some maintenance, but provide a seamless user experience, in which most will never notice its existence. These door bottoms automatically retract into the housing when the door opens, and lower when the door closes, to provide the needed protection.

Specifying door bottoms with a minimum capacity of 2.5 million cycles is imperative. These are required in specific openings such as stairwells or those with fire or sound ratings. They are available in a variety of thicknesses and finishes. Some automatic door bottoms are even surface mounted, so they can be installed without removing the door.

An automatic door bottom is activated in one of two ways. One is the standard opening and closing of the door. If the door is closed, the threshold functions as a latch, activating the door bottom and allowing the seal to drop down. When the door is opened, the pin hitting against the stop retracts in the door bottom and the seal is then concealed into the housing.

The more innovative approach is to have an electronically retracting door bottom that can be activated with a switch—a keypad, key switch, or a standard momentary switch with no credential requirements. This feature is extremely useful in settings where sound control is particularly crucial, such as law firms and doctor’s offices, and room occupants are also made aware of the feature and its importance. It can also be specified whenever a complete seal is required, such as during a fire.


Gasketing is one of most misunderstood and underspecified material. Gasketing should not be categorized as a door accessory, but rather recognized as an integral and significant component to a successfully operating, code-compliant, and sustainable opening. However, its effectiveness is dependent on proper specification and installation.

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