Rolling Door Hood

The rolling door hood is the formed sheet metal housing that mounts horizontally above a rolling steel door opening and encloses the barrel assembly, the coiled curtain, and the counterbalance springs when the door is in the open position. It serves three functions: physical protection for the coil, weather exclusion, and a finished appearance on interior or exterior installations.

The hood is typically a three-sided box (two end caps plus a curved or angular shroud) fabricated from 22-gauge or 18-gauge galvanized steel. The opening faces downward toward the opening, so the curtain slats can travel in and out freely. End caps bolt to the hood brackets at each jamb and also tie into the support straps or mounting angles that hold the barrel shaft.

Hood sizing is driven by curtain coil diameter. As curtain slats pile up around the barrel during door travel, the coil grows. A 10-foot-tall door curtain on a 3-inch-diameter barrel might reach a coil diameter of 18 to 24 inches when fully open. The hood must be large enough to contain that coil without the slats rubbing the inside of the hood and generating noise or wear. Installers calculate required hood height from the curtain thickness, slat count, and barrel diameter before specifying the door.

On insulated commercial doors, the hood may include an internal baffle that partially seals the open end and reduces cold air convection through the coiled curtain. On fire-rated rolling doors, the hood is part of the listed assembly and must match the door label; field-fabricated hoods cannot substitute.

The hood connects functionally to the rolling door guides at each side and to the bottom bar through the curtain. When the barrel rotates during operation, the curtain feeds out of the bottom of the hood, travels down the guides, and seats against the floor.