Abstract: A method for producing a covering element made from natural fibres, in particular cellulose, impregnated with bitumen, includes a step of coating at least one of two faces of a fibre mat (4) followed by a step of impregnating with bitumen, the coating being carried out with a liquid composition (5) including at least one resin and/or at least one pigment. The liquid composition is a dye composition including at least one pigment and at least one resin, and the method involves adding an additive to the liquid composition (5), the additive having fireproof properties and including at least graphite and a cooling agent. Preferably, the mat (4) is coated with the liquid composition including the fireproof additive using a roller.

Abstract: Method for designing a corrugated roofing sheet made of natural fibers, impregnated with bitumen including a uniform pattern of mutually parallel alternating corrugations borne by a mid-plane, the corrugations defining rounded crests each separated from the next by a rounded trough, the crests and trough being connected by alternately inclined portions, the transverse offset between two successive crests being equal to the transverse offset between two successive troughs and defining the pitch P of the corrugations, the sheet having a thickness E of material substantially constant over its extent, and a height H being twice the distance between the mid-plane and the exterior surface of a crest or twice the distance between the mid-plane and the exterior surface of a trough, these two distances being identical. The height, thickness and pitch values are determined by Fi<H3/(8×E×(H+P))<Fs, where Fi=25 mm and Fs=35 mm.

Abstract: A machine for dusting a shape with particulate matter, the shape being a profiled roof tile including raised patterns extending in the lengthwise direction thereof, and including raised portions laterally separated from hollow portions by sloped portions, the tile having a predetermined width, and being preferably corrugated, the machine including a dusting element forming a homogeneous linear curtain of particulate matter falling across the width of the tile, the tile travelling longitudinally under the linear curtain. Deflectors of the curtain are arranged above the tile to intercept the particulate matter above the areas at the bottom of the sloped portions and redistribute the intercepted particulate matter towards an intermediate level of each corresponding sloped portion in order for the amount of particulate matter on the surface of the plate ultimately to be substantially homogeneous after a portion of intercepted particulate matter has slid towards the bottom of the sloped portion.

Abstract: A method for continuously producing a mat of cellulose fibers intended for producing roofing elements made from bitumen-impregnated cellulose fibers, from a dilute slurry of cellulose fibers spread by a headbox on a dewatering fabric of a forming table having a predefined width, the dewatering fabric moving between an inlet of the forming table at the headbox side and an outlet of the forming table, moving the dilute slurry towards the outlet, gradually removing the liquids of the dilute through the dewatering fabric during the movement to obtain, at the outlet, the mat having a thickness of at least 2 mm, the dilute slurry having a certain level of pre-existing mineral materials. The method involves adding mineral material to the cellulose fibers by spraying a controlled quantity of aqueous solution or dispersion of mineral fillers over the width of the forming table onto the surface of the dilute slurry.

Abstract: Disclosed is a method of fabricating bitumen impregnated cellulose ridge tiles, each ridge tile having the general shape of a profiled ridge tile plate of cross-section symmetrical about a vertical longitudinal midplane and that includes a downwardly concave central ridge extended laterally on either side by a flat that terminates in a downwardly concave corrugation, the ridge tile further including a series of ribs at each longitudinal end, the panel being in the form of a section member of cross-section that is made up by juxtaposing at least two cross-sections, each identical to the cross-section of the ridge tile plate, with transverse ribs in the vicinity of the longitudinal ends of the panel and on either side of at least one virtual transverse separation line extending between longitudinal panel edges. The panel is cut along a longitudinal line between the juxtaposed ridge tile sections.

Abstract: Method for designing a corrugated roofing sheet made of natural fibres, impregnated with bitumen including a uniform pattern of mutually parallel alternating corrugations borne by a mid-plane, the corrugations defining rounded crests each separated from the next by a rounded trough, the crests and trough being connected by alternately inclined portions, the transverse offset between two successive crests being equal to the transverse offset between two successive troughs and defining the pitch P of the corrugations, the sheet having a thickness E of material substantially constant over its extent, and a height H being twice the distance between the mid-plane and the exterior surface of a crest or twice the distance between the mid-plane and the exterior surface of a trough, these two distances being identical. The height, thickness and pitch values are determined by Fi<H3/(8×E×(H+P))<Fs, where Fi=25 mm and Fs=35 mm.

Abstract: A method of fabricating a roof-covering element out of molded cellulose impregnated with bitumen for roofing. In a first step, an element, preferably of cellulose, is made by hot compression molding in a mold, in a second step, once the element has a dry matter content of at least 60% when extracted from the mold, the element is covered in a pigmented varnish and dried, and in a third step, once the element has a dry matter content of at least 98%, the element is impregnated with hot bitumen. Specific operating conditions are given. The covering elements include in particular a ridge side portion, a ridge cap, a ridge-covering kit, a fillet or curb, and a hip.