Sectional Garage Door

Overview

A sectional garage door is the most common overhead garage door: a curtain of horizontal panels hinged together that rolls from vertical, closed over the opening, up through a quarter-turn to horizontal storage along the garage ceiling. Because the panels articulate, the door takes up no swing space outside or inside the opening. This is an insulated door, steel-skinned panels with a foam core, for thermal performance and rigidity.

Construction

The curtain is four Door Panel Section sections, each two roll-formed steel skins sandwiching a foamed-in-place polyurethane core, capped by end stiles. The sections flex relative to one another at the Hinge Set: intermediate centre hinges at each joint and numbered end hinges that also carry the roller stems. Those stems hold the Roller Set, sealed-bearing nylon rollers that ride inside the Track Assembly, vertical track up each jamb, a curved radius section, and horizontal track suspended from the structure.

The door's weight is offset by the Counterbalance Assembly. A wound torsion spring on a shaft above the header stores energy as the door lowers; grooved cable drums on the shaft wind galvanized lift cables that run down to the bottom corner brackets, so the spring all but cancels the door's weight and the door can be lifted with one hand or a modestly sized opener.

Weather sealing comes from a flexible bottom astragal and perimeter Jamb Seal flaps, and tongue-and-groove strips between sections. A manual slide-bar lock secures the closed door, and U-channel reinforcing struts stiffen the top and operator sections against wind load and the pull of a powered opener.