Abstract: A construction material in sheet form having at least two water barriers including a water-impermeable foamed intermediate layer, a mineral-based interior layer, and a prefinished, weatherable, water-impermeable non-asphaltic outer layer, with adjoining layers firmly adhered. Sheets of the construction material having a foamed intermediate layer and mitered edges exposing the foamed layers are joined by the steps of positioning the sheets with the mitered edges abutting opposite sides of the stem of a bulb-T rafter, the sheets being supported by the cross-member of the bulb-T rafter, forming a foam filler in the cavity created by the abutted mitered edges, and sealing the cavity with weatherable tape. A roof deck for use with bulb-T rafters, the roof deck constructed of the aforementioned sheets joined by the aforementioned method is also shown.

Abstract: Apparatus for sealingly joining sheets of construction material laid with edges abutting over an underlying frame and having edges rabbeted to form a joint channel including a pad for lying in the channel, a cap permanently adhered to the pad member and having edges extending past the pad for sealingly contacting the unrabbeted sheet surfaces, a metal strip embedded in the pad, and screws for securing the metal strip to the frame to capture the rabbeted surfaces of the sheets.

Abstract: A method and apparatus for selectively comminuting particles of a frangible material for the production of filter aid, the apparatus including an air-conveying system for carrying entrained particles of varying masses, a venturi for accelerating the air stream and entrained particles, a duct for receiving the accelerated air stream and particles, and impact bars mounted in the duct for selectively fragmenting the entrained particles. The impact bars are positioned in the accelerated air stream to establish adverse pressure fields which classify the entrained particles and which provide impact surfaces to fragment particles greater than a predetermined mass, the rest of the particles being deflected around the bars by the action of the adverse pressure fields.