A specification guide to commercial door threshold types, ADA compliance, material selection, and application criteria for interior and exterior openings.
This guide answers: How do you select a commercial door threshold that meets ADA height requirements?
Role of Thresholds in Commercial Door Assemblies
A threshold is the horizontal component installed at the bottom of a door frame, spanning the width of the opening at floor level. Thresholds serve multiple functions: they provide a transition between flooring surfaces, seal the gap between the door bottom and the floor to control air infiltration, water penetration, and light transfer, and they contribute to the structural integrity of the door frame at the floor line.
In commercial construction, threshold selection is governed by accessibility requirements (ADA/ABA), energy codes, fire ratings, and environmental exposure. The wrong threshold can create an ADA violation, compromise a fire-rated opening, or allow water intrusion at an exterior door. CDF Distributors supplies Pemko thresholds through its FlashShip program, providing access to a comprehensive catalog of threshold profiles for every commercial application.
ADA Threshold Height Requirements
The Americans with Disabilities Act Accessibility Guidelines (ADAAG) and ICC A117.1 establish maximum threshold heights for accessible routes. These requirements apply to all doors on an accessible route, including entries, interior passages, and restroom doors.
- Maximum height for existing buildings: 3/4 inch (19 mm)
- Maximum height for new construction: 1/2 inch (13 mm)
- Beveled edges required on any threshold higher than 1/4 inch (6 mm)
- Maximum bevel slope: 1:2 (one unit vertical per two units horizontal)
- Exterior sliding doors: 3/4 inch maximum with beveled edges
Threshold Profile Types
Commercial thresholds are manufactured in several profile configurations. Each profile addresses a specific combination of accessibility, weather sealing, and traffic requirements.
Saddle Thresholds
Saddle thresholds (also called flat-top or fluted-top thresholds) have a raised center section that creates a dam between the interior and exterior. The raised profile provides effective weather sealing for exterior doors. Standard saddle thresholds are available in heights from 1/4 inch to 1 inch. For ADA compliance in new construction, the saddle height must not exceed 1/2 inch and must have beveled edges if the height exceeds 1/4 inch. Saddle thresholds are the most common type for exterior commercial entries.
Bumper Thresholds
Bumper thresholds feature a raised resilient seal (typically neoprene or silicone) along the top surface. When the door closes, the door bottom compresses against the bumper seal, creating an air and water barrier. Bumper thresholds provide superior weather sealing for high-exposure exterior doors. The overall height including the resilient seal must be evaluated for ADA compliance.
Offset Thresholds
Offset thresholds have an asymmetric profile with one side higher than the other. This design accommodates doors that swing over the threshold in one direction and provides a step-down on the opposite side. Offset profiles are used when there is a change in floor elevation between the two sides of the opening. The higher side must be evaluated against ADA maximum height requirements.
Thermal Break Thresholds
Thermal break thresholds incorporate an insulating barrier (typically a polyurethane or PVC separator) between the interior and exterior sections of the threshold. This break interrupts the thermal conductivity path through the metal threshold, reducing energy loss. Thermal break thresholds are required by energy codes in many climate zones for exterior openings and are essential for maintaining building envelope performance in heated or cooled facilities.
Panic/Exit Device Thresholds
Panic thresholds (also called exit device thresholds) are low-profile thresholds designed specifically for openings equipped with panic hardware (exit devices). These thresholds have a flat or very low-profile design to avoid interfering with the panic bar's vertical rod or the door's swing arc. Many panic thresholds use a combination of a low saddle profile with an integrated seal to maintain weather resistance without exceeding ADA height limits.
Threshold Materials
The material composition of a threshold affects its durability, thermal performance, corrosion resistance, and cost.
- Aluminum (mill finish or anodized): The most common commercial threshold material. Lightweight, corrosion-resistant, and available in a wide range of profiles. Anodized finishes provide additional surface hardness and color options.
- Bronze: Premium threshold material with high corrosion resistance and aesthetic appeal. Used in institutional and high-end commercial entries. Available in satin, polished, and oil-rubbed finishes.
- Stainless steel: High corrosion resistance for harsh environments (coastal, industrial, food service). Available in Type 304 and Type 316 grades.
- Aluminum with thermal break: Aluminum threshold with integrated polyurethane or PVC thermal separator. Combines aluminum's durability with reduced thermal conductivity.
Exterior vs Interior Threshold Selection
Exterior thresholds must address weather sealing, thermal performance, and exposure to moisture, UV, and temperature cycling. Interior thresholds primarily manage floor transitions and accessibility compliance.
- Exterior entries: Saddle or bumper profile with weather seal; thermal break in climate-controlled buildings; aluminum or stainless steel for corrosion resistance
- Interior corridors: Low-profile saddle or flat threshold; ADA height compliance; aluminum is standard
- Restrooms: Low-profile or recessed threshold; ADA compliance critical; moisture-resistant material
- Exterior doors with panic hardware: Low-profile panic threshold with integrated seal; must not interfere with exit device operation
CDF's Threshold Selection
CDF's ProBuilder configuration tool includes threshold selection as part of the door assembly process. When specifying a complete opening, ProBuilder validates that the selected threshold is compatible with the door, frame, and hardware configuration. This ensures the complete assembly meets ADA, fire rating, and energy code requirements.
Configure Your Door Assembly
CDF's ProBuilder tool includes threshold selection as part of the complete door assembly configuration. Select from Pemko saddle, bumper, thermal break, and panic threshold profiles, validated for compatibility with your door, frame, and hardware. For assistance, call (855) 769-9895 or email sales@cdfdoors.com.
Frequently Asked Questions
What is the maximum threshold height allowed under ADA for new construction?
The maximum threshold height for new construction on accessible routes is 1/2 inch (13 mm). Any threshold higher than 1/4 inch must have beveled edges with a maximum slope of 1:2. For existing buildings undergoing renovation, the maximum is 3/4 inch with beveled edges.
What type of threshold should I use for an exterior commercial entry?
Exterior commercial entries typically require a saddle or bumper threshold with weather sealing. In climate-controlled buildings, a thermal break threshold reduces energy loss through the threshold. The threshold material should be corrosion-resistant (aluminum, bronze, or stainless steel) based on the environmental exposure.
Do I need a thermal break threshold?
Thermal break thresholds are required by energy codes in many climate zones for exterior openings in heated or cooled buildings. Check your local energy code (typically IECC or ASHRAE 90.1) and climate zone to determine whether a thermal break is mandatory. Even where not required by code, thermal break thresholds improve building envelope performance.
What threshold works with panic exit devices?
Panic (exit device) thresholds have a low-profile design that avoids interfering with the panic bar's operation or vertical rod mechanisms. These thresholds typically combine a flat or low saddle profile with an integrated seal. Pemko manufactures specific panic threshold profiles for this application.
Does CDF supply Pemko thresholds?
Yes. CDF Distributors supplies Pemko thresholds, in addition to other brands. Thresholds can be specified as part of a complete door assembly in CDF's ProBuilder configuration tool, which validates compatibility with the door, frame, and hardware.
Can a threshold affect the fire rating of an opening?
Yes. Fire-rated openings have specific requirements for the gap between the door bottom and the floor or threshold. The threshold must maintain the required clearance specified by the door and frame manufacturer's fire-rated listing. Using a non-listed threshold or creating excessive clearance can void the fire rating of the assembly.
About This Guide
This guide reflects CDF Distributors' standard specifications and field-tested recommendations used by commercial contractors nationwide. The information is provided for specification and selection purposes. Always verify requirements with the Authority Having Jurisdiction (AHJ) for your project location.
For questions or to order a complete door assembly, contact CDF at (855) 769-9895 or sales@cdfdoors.com. Configure your assembly online at ProBuilder: cdfdistributors.com.
