What is a drain pan threshold and when is it required?
A drain pan threshold is a threshold assembly that includes a recessed pan or trough beneath the threshold saddle to collect water that passes the primary weather seal. The pan directs water back to the exterior through weep holes. Drain pan thresholds are specified for exterior door openings exposed to wind-driven rain, standing water, or heavy storm conditions where a standard flat threshold would not prevent water infiltration.
What is a thermal break threshold?
A thermal break threshold has a non-conductive material (typically polyamide or PVC) between the interior and exterior portions of the metal extrusion. This interrupts the conductive heat path through the threshold, reducing energy transfer and preventing condensation on interior surfaces. Thermal break thresholds are specified in climate zones with significant heating or cooling loads.
What threshold materials are used for exterior commercial doors?
The three primary materials are aluminum (most common, lightweight, corrosion-resistant), bronze (higher corrosion resistance, specified for coastal and architectural applications), and stainless steel (chemical resistance, high traffic, sanitation requirements). Grade 304 stainless is standard, and grade 316 is used for coastal or chemical-exposure conditions.
How do you waterproof the connection between the threshold and the door frame?
The frame-to-threshold connection is sealed with compatible sealant (silicone or polyurethane) at the jamb and head intersections. The waterproofing membrane from the wall system must extend across the sill area and lap over the drain pan flanges. All sealant joints should use backer rod to maintain proper joint geometry and movement capacity.
What are the ADA requirements for exterior door thresholds?
Under ADA and ICC A117.1, exterior door thresholds are generally limited to 3/4 inch maximum height. Where the threshold height exceeds 1/4 inch, both edges must be beveled. When specifying drain pan or thermal break thresholds, the combined height of all components must stay within this limit.
Can you order a complete exterior door assembly with a waterproof threshold through CDF?
Yes. CDF's ProBuilder tool allows you to configure a complete exterior door assembly including the Pemko threshold, door, frame, weatherstripping, and hardware as a single coordinated package. Contact CDF at (855) 769-9895 for assistance.