The type of seal between the sections: triple-contact PVC molding mechanically linking the front and back metal sheets prevents contact between them thus eliminating any thermal transfer (fig. #1). Note that this feature is not available on our G-8000 and G-8500 models.

Wood end blocks perform a dual purpose: they insure a thermal break while providing better fastening of the end hinges which are attached to a 1 3/4”-thick piece of solid wood with lag screws (fig. #2). Standard with other manufacturers for end hinge fastening is a self-tapping screw going through a steel end cap, door sheet and hinge strip for a total thickness of approximately 0.11” (2.7 mm), thus engaging only about 2 or 3 threads (fig. #3). Note: a steel end cap allows thermal transfer, thus reducing the advertised R-value.

The compostition of the bottom weather seal: "U"-shaped, EPDM rubber mounted on an extruded PVC retainer (fig. #4). The high rubber content allows the seal to remain flexible during cold weather, maintaining the seal unlike other products that have a low rubber content which can harden thereby causing seal failure,  cracking and splitting over time.