Patent ID: 8277586

Claim:
A production process for a board of hydraulic binder, the process comprising: 1) pouring a hydraulic binder slurry on a first facing material supported by a conveyor belt and at least two longitudinal forming strips, and covering the hydraulic binder slurry with a second facing material so as to obtain a preform; 2) producing an imprint in an upper part or a lower part of the preform using at least one lath having at least two distal parts and comprising a plurality of bars embedded in a polymer matrix at the level of the distal parts; the lath being withdrawn before hydraulic setting begins; 3) allowing for hydraulic setting of the hydraulic binder slurry to take place; and 4) cutting the preform at a level of a tapered section created by the imprint into the board of hydraulic binder with the facing materials on each of its sides, the board comprising on one side two first tapered parallel edges and on the one side or another side two second tapered parallel edges perpendicular to the first.