Disclosed herein are plaster boards having a first surface and an opposing second surface, and a first edge and an opposing second edge that bound the first surface and the second surface. The first surface includes a first section and a second section, the first section being raised compared to the second section, the second section abutting the second edge. The second surface includes a first section and a second section that are separated by a boundary between the first edge and the second edge. The first section of the second surface is substantially parallel to the first section of the first surface. The second section of the second surface slopes toward the first surface from the boundary toward the second edge. Methods for making the plaster boards involve forming wet plaster material and drying the wet plaster material such that the wet plaster material hardens into a plasterboard.

A method for production of a gypsum fiberboard panel, has the following method steps: production of a mixture of calcined gypsum and fibers; application of the mixture to a gas-permeable and/or air-permeable and/or liquid-permeable conveyor that continuously moves in an advancing direction, at an advancing speed; pre-compaction of the mixture; wetting of the mixture with setting water; post-compaction of the mixture; pressing the mixture to form a gypsum fiberboard panel strand; cutting the gypsum fiberboard panel strand into individual gypsum fiberboard panels; drying the gypsum fiberboard panels; and if necessary, finishing and/or coating the dried gypsum fiberboard panels; wherein for pre-compaction, the mixture is sprayed with a water mist and has a partial vacuum applied to it. Furthermore, an apparatus produces a gypsum fiberboard panel, in particular by carrying out the method, and a gypsum fiberboard panel is produced using the method and/or using the apparatus.

Gypsum boards formed from synthetic gypsum and other gypsum sources having high chloride salt concentrations. Gypsum boards may include a board core including set gypsum. A total concentration of the chloride anion in the board core ranges from about 500 ppm to about 3000 ppm, typically about 1000 ppm to about 3000 ppm, based on weight of the calcium sulfate hemihydrate. An inner surface of a front paper cover sheet contacts a first face of the board core. An inner surface of a back paper cover sheet contacts a second face of the board core. A starch layer coats the inner surface of at least one of the front and back cover sheet. Methods of making the gypsum board, and a wall system for employing the gypsum boards, are also provided.

Gypsum boards formed from synthetic gypsum and other gypsum sources having high chloride salt concentrations. The gypsum boards may include a set gypsum board core layer between a front and back paper cover sheets. The back paper cover sheet has a plurality of perforations extending therethrough. Methods of making the gypsum boards, and a wall system for employing the gypsum boards, are also provided. The concentration of the chloride anion in aqueous gypsum slurry used to make the set gypsum board core layer and to perform the methods of the invention may range from about 500 ppm to about 3000 ppm, typically from about 500 ppm to about 2000 ppm per 1,000,000 parts by weight calcium sulfate hemihydrate, more typically from about 500 ppm to about 1500 ppm per 1,000,000 parts by weight calcium sulfate hemihydrate.

A building panel with a high degree of isotropy with regard to the load bearing capacity and flexural strength. The building panel includes a first section and a second section, each section including at least one layer, each of the at least one layer having fibers, whereby the fibers are distributed substantially homogeneously throughout each layer, substantially parallel to the main surfaces of the panel and oriented predominantly in the same direction and the sections are firmly joined in transverse direction, and the first section is thinner than the second section.

Embodiments of a system and a method for manufacturing a gypsum board can be used to produce a gypsum board having at least one perforated cover sheet via a cover sheet perforator system. The cover sheet perforator system can include a perforator roller is disposed downstream of a forming station along a machine direction, a roller support frame for rotatably supporting the perforator roller such that its rotational axis extends along the cross-machine direction, and a motor arranged with the perforator roller to rotate the perforator roller about the rotational axis. The drive motor can be adapted to rotate the perforator roller with a tangential speed substantially equal to the line speed to produce a series of perforation holes in an upwardly-facing cover sheet as the gypsum board moves past the perforator roller.

Mat-faced cementitious board including: (a) a cementitious core; (b) a fibrous mat having an inner first surface facing at least one face of the cementitious core, and an outer second surface, wherein the inner first surface and the outer second surface are opposed; (c) a hydrophobic, non-setting coating resulting from applying to the outer second surface of the fibrous mat a layer of hydrophobic finish composition including: (i) about 50 to about 80 weight % non-setting, inorganic filler having a mean particle diameter of about 12 microns to about 35 microns, (ii) about 20% to about 50 weight % an aqueous dispersion of a film-forming polymer, (iii) 0% to about 30 weight % additional water; (iv) an absence of fly ash, (v) an absence of pozzolanic material, (vi) an absence of hydraulic cement, (vii) an absence of calcium sulfate hemihydrate, and (viii) an absence of calcium sulfate anhydrite.

A composition, utility material, and method of making a utility material is disclosed. A composition having an improved setting time may include a plurality of microparticles mixed with a sodium silicate binder and an isocyanate setting agent, where the microparticle composition has a setting time of less than or equal to one hour. A utility material may be a wallboard that includes the composition.

In general, the present invention is directed to a building panel, such as a gypsum board, comprising a core having a first side and a second side opposing the first side and at least one facing material having a coating comprising at least one fungicide, at least one polymeric binder, and at least one pigment. The panel satisfies at least one of the following: the board exhibits a rating of 2 or less when tested in accordance to ASTM G21-15 or the board exhibits a rating of at least 8 when tested in accordance to ASTM D3273-16. The panel may also exhibit at least a Level 3 finish.

Disclosed herein are plaster boards having a first surface and an opposing second surface, and a first edge and an opposing second edge that bound the first surface and the second surface. The first surface includes a first section and a second section, the first section being raised compared to the second section, the second section abutting the second edge. The second surface includes a first section and a second section that are separated by a boundary between the first edge and the second edge. The first section of the second surface is substantially parallel to the first section of the first surface. The second section of the second surface slopes toward the first surface from the boundary toward the second edge. Methods for making the plaster boards involve forming wet plaster material and drying the wet plaster material such that the wet plaster material hardens into a plasterboard.