Doors having stile and rail frames and center elements secured to the stile and rail frames and the center elements have margins inwardly where the center elements and the door frames overlap and openings extend through the margins outwardly from openings in skins, and inside and outside skins are secured to the stile and rail frames. The inside and outside skins have openings adjacent to and laterally or inwardly spaced apart from the openings through the margins whereby air flows through the openings in the inside skin, through the openings in the margins, and through the openings in the outside skin in a non-linear manner to prevent pressure build up in rooms to comply with the Department of Energy maximum recommended room pressure of three pascals or less.

Gypsum based compositions, processes for making same, and articles made therefrom. In one example, the gypsum based composition can include about 1.5 wt % to about 3 wt % of a starch, about 11 wt % to about 14 wt % of a paper, about 0.7 wt % to about 2.3 wt % of vermiculite, about 1.3 wt % to about 3 wt % of a plurality of reinforcing fibers, about 7 wt % to about 10 wt % of a binding agent, about 2 wt % to about 4 wt % of perlite, and about 65 wt % to about 75 wt % of a calcium sulfate, where all weight percent values are based on a combined weight of the starch, paper, vermiculite, plurality of reinforcing fibers, binding agent, perlite, and calcium sulfate.

Hollow core door apparatus for preventing the build up of pressure in a room includes an inside door skin and an outside door skin, and the door skins include openings through which air flows. A center panel is disposed between and spaced apart from the skins. The center panel has an outer perimeter defined by notches through which air flows. Tabs between the notches are used to secure the center panel to the inside and outside door skins. Air flow from the room is through the opening in the inside skin, around the outer perimeter of the panel, and outwardly from the door and room through the outside skin in a non-linear manner. The door alone with normal undercuts and margins, and with its notches and associated structural elements, achieves a Rater-measured pressure differential of equal to or less than 3 pascals with respect to the main body of the building when bedroom room doors are closed. For larger rooms with air flow greater than one hundred fifty cfm, the pressure is equal to or less than 5 pascals. Air flow is controlled by a plurality of movable panels disposed adjacent to the outer perimeter of the center panel. Sensor elements for sensing desired information and for providing output signals, including signals for actuating the movable panels, are included. The air flow outwardly through the door is at least as great as the air flow into the room, thus the door provides internal transfer of air through the door to eliminate air pressure build up in a room, and at the same time limits light, sight, and sound travel through the door.

Hollow core door apparatus for preventing the build up of pressure in a room having a register through which air flows into the room and the door includes an inside door skin and an outer door skin, and the door skins includes openings through which air flows into and out of the room and which openings have substantially the same area to provide for a non-linear flow of air through the door to prevent the build up of pressure in the room. An embodiment combining a noxious gas absorbent material with the pressure build up prevention capability is also illustrated.

The present invention relates to shaker doors with solid cores and methods for making the same. The shaker doors contain different core materials at the recessed panel than the raise peripheral region to provide dimensional stability and reduced distortion when the doors are exposed to high humidity. The devices and methods also provide for easy assembly of solid core shaker doors, including fire rated doors.