Pemko 434APKL42 42" 3' 6" Full Mortise Automatic Door Bottom with PemkoPrene Mill Finish Aluminum Finish

The 434APKL42 full mortise automatic door bottom installs into the bottom rail of doors to seal the gap between door and threshold. This weatherization component prevents air infiltration, moisture, dust, and sound transmission through the door assembly. Pemko engineered this unit with a low-force actuating mechanism that drops the PemkoPrene seal bar when the door closes, creating an effective barrier against environmental elements.

The reversible design works on both wood and metal doors in commercial and institutional applications. The unit ships custom cut to 42 inches and can be field-trimmed up to 2 inches for exact fit. The mill finish anodized aluminum housing provides corrosion resistance while the proprietary PemkoPrene seal material maintains flexibility across temperature ranges. Installation hardware comes included with the unit.

Material	Anodized Aluminum with PemkoPrene Seal
Length	42" (3' 6")
Mounting	Full Mortise
Finish	Mill Aluminum
Warranty	5 Years Limited

This door bottom meets UL 10C positive pressure fire testing standards and UL 1784 air leakage requirements. It also complies with ANSI/BHMA A156.22 door gasketing standards, ASTM E283 air infiltration testing, and ASTM E90 sound transmission ratings. The unit carries GREENGUARD Gold certification for low chemical emissions.

Fire-rated door assemblies require tested components that maintain integrity under UL 10C fire testing conditions. For buildings with egress requirements, proper door sealing supports NFPA 101 Life Safety Code compliance by controlling smoke migration during fire events.