Imperial Thresholds


Achieve superior results with Quanex Building Products’ Imperial thresholds designed to eliminate air and water infiltration, resist weathering and provide a long-lasting natural appearance door system.  All of our testing data has been independently verified by third-party sources.

5Y High-Performance Thresholds

5Y Composite Thresholds incorporate the patented ImperiSeal™ technology, a continuous filament that positively seals the adjusting rail to the deck of the sill, thus eliminating any chance of water intrusion through the threshold. The 5Y carries numerous independently verified third-party air and water infiltration certifications, including ratings in excess of DP50.

5C “Can-Am” Sill

Exterior door certification requirements in Canada have led to breakthroughs in threshold design that are adaptable to expanded widths, while virtually eliminating air and water infiltration. Imperial 5C Thresholds are ideal for high-end applications that require the very best performance and long-term durability. 

5H Hybrid-Technology Thresholds

5H Thresholds provide an excellent balance between economy and performance. The 5H combines the patented ImperiSeal™ technology that eliminates any chance of water intrusion through the threshold with a durable, injection-molded base. 

Imperial 5E Rail Over Dam Threshold

When economy is a primary concern but quality cannot be sacrificed, look to Imperial Products’ 5E Thresholds designed to provide simplicity and performance at a lower cost.

Ideal for secondary doorways, such as garage entrances, or for new construction, 5E is a proven performer that incorporates many of Quanex’s high-end technologies. 

Contact us to learn more about our array of threshold products or for assistance in meeting industry performance criteria. View our Prehung Door Installation Instructions.