# US 5,704,179 A · Finishing and roof deck systems containing fibrous mat-faced gypsum boards > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,704,179 A - Document ID: US5704179A - Status: Granted - Kind: A - Application number: 08/187,199 - Filed: 1994-01-26 - Granted: 1998-01-06 - Earliest claimed: 1984-02-27 - Assignees: Georgia-Pacific Corporation - Inventors: Charles W. Lehnert; Brian G. Randall - Web page: https://patentgrep.com/patent/US5704179A ## CPC - B32B 13/14: next to a fibrous or filamentary layer - B28B 19/0092: {to webs, sheets or the like, e.g. of paper, cardboard} - B28B 23/0006: {the reinforcement consisting of aligned, non-metal reinforcing elements} - E04C 2/043: {of plaster (E04C2/049 takes precedence)} - E04C 2/284: at least one of the materials being insulating - E04C 2/288: composed of insulating material and concrete, stone or stone-like material - E04D 11/02: Build-up roofs, i.e. consisting of two or more layers bonded together in situ, at least one of the layers being of watertight composition (gravelling of flat roofs E04D7/00; venting or ventilation E04D13/17) - E04D 13/1643: {the roof structure being formed by load bearing corrugated sheets, e.g. profiled sheet metal roofs} - E04D 13/1668: {the insulating material being masses or granules applied in situ} - E04F 13/047: {Plaster carrying meshes} - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM - B28B: SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER (foundry moulding B22C; working stone or stone-like material B28D; shaping of substances in a plastic state, in general B29C; making layered products not composed wholly of these substances B32B) - E04C: STRUCTURAL ELEMENTS; BUILDING MATERIALS (for bridges E01D; specially designed for insulation or other protection E04B; elements used as building aids E04G; for mining E21; for tunnels E21D; structural elements with broader range of application than for building engineering F16, particularly F16S) - E04D: ROOF COVERINGS; SKY-LIGHTS; GUTTERS; ROOF-WORKING TOOLS (coverings of outer walls by plaster or other porous material E04F13/00) - E04F: FINISHING WORK ON BUILDINGS, e.g. STAIRS, FLOORS (windows, doors E06B) ## Abstract Finishing systems and roof decks are provided which include a gypsum board having a set gypsum core faced with a fibrous mat. The gypsum core includes one or more additives which are effective in simultaneously improving the water and fire resistance of the board. In preferred embodiments, the board has sufficient water-resistant additive for absorbing less than about 10% water in an ASTM C-473 test. ## Claims ### Claim 1 A plaster lath finishing system for use in a building comprising a support member containing a fibrous mat-faced gypsum board comprising a gypsum core having one or more additives therein which simultaneously improve the water resistance and fire resistance of the core, and a finishing material overlying said board. ### Claim 2 (depends on 1) The plaster lath finishing system of claim 1, wherein said system is located in the interior of a structure, and said finishing material comprises a thin plaster coating. ### Claim 3 A system comprising a roof deck which includes supporting means and a gypsum board overlying said supporting means, said board comprising: (a) a gypsum core having one or more additives therein which improve the water resistance of the core; and (b) a glass fiber mat facing at least one side of said core. ### Claim 4 (depends on 3) A roof deck according to claim 3, wherein insulating material is sandwiched between said supporting means and said gypsum board. ### Claim 5 (depends on 3) A roof deck according to claim 3 including a cementitious composition overlying said gypsum board, and an exterior finishing material overlying said cementitious composition. ### Claim 6 (depends on 5) A roof deck according to claim 5 including a mesh-like material sandwiched between said gypsum board and said cementitious composition. ### Claim 7 A system comprising a roof deck which includes supporting means and a gypsum board overlying said supporting means, said board comprising: (a) a gypsum core having one or more additives therein which improve both the water resistance and fire resistance of the core, one of said additives comprising mineral fibers for improving the fire resistance of the core; and (b) a glass fiber mat facing at least one side of said core. ### Claim 8 (depends on 7) The system of claim 7 wherein said gypsum board has each of its core faces covered with said glass fiber mat, with the mat of at least one of the faces being adhered to the core by set gypsum penetrating into the thickness of the mat. ### Claim 9 (depends on 8) The system of claim 8 wherein said set gypsum penetrates but partway into the thickness of the mat such that the outer surface of said mat is substantially free of set gypsum. ### Claim 10 (depends on 7) The system of claim 7 wherein said support means comprises metal sheet. ### Claim 11 (depends on 10) The system of claim 10 further comprising a finishing material overlying said gypsum board. ### Claim 12 (depends on 11) The system of claim 11 wherein said finishing material comprises one or more alternating layers of asphalt and roofing felt. ### Claim 13 (depends on 12) The system according to claim 12 further including insulating material sandwiched between said metal sheet and said gypsum board. ### Claim 14 (depends on 13) The system according to claim 13 wherein said insulating material is expanded polystyrene. ### Claim 15 (depends on 14) The system according to claim 14 wherein said support comprises corrugated metal sheet. ### Claim 16 (depends on 7) The system of claim 7 wherein said mineral fibers comprise glass fibers. ### Claim 17 (depends on 16) The system of claim 16 wherein said glass fibers comprise chopped glass fibers. ### Claim 18 (depends on 7) The system of claim 7 wherein said core comprises at least about 0.03 wt. % mineral fibers. ### Claim 19 (depends on 7) The system of claim 7 wherein said core has a density of less than about 55 lbs. per cubic foot. ### Claim 20 (depends on 19) The system of claim 19 wherein said core has a density of from about 45 to about 55 lbs. per cubic foot.