Fiber board product comprising a) fibers in an amount from 50.0 to 99.0 parts by weight (d/d), based on the total dry weight of the fibers and the at least one particulate calcium carbonate-containing material, wherein the fibers in an amount of i) 0 to 20.0 wt.-%, based on the total amount of dry fibers, are of a size which is fractioned at a mesh sieve width of 0.05 mm, ii) 50.0 to 90.0 wt.-%, based on the total amount of dry fibers, are of a size which is fractioned at a mesh sieve width of 1.0 mm, and iii) 70.0 to 100.0 wt.-%, based on the total amount of dry fibers, are of a size which is fractioned at a mesh sieve width of 3.0 mm, as determined by sieve analysis, b) at least one particulate calcium carbonate-containing material in an amount from 1.0 to 50.0 parts by weight (d/d), based on the total dry weight of the fibers and the at least one particulate calcium carbonate-containing material, the at least one particulate calcium carbonate-containing material having a weight median particle size d 50 of 0.5 to 150.0 μm, and additionally c) at least one binder in an amount from 0.05 to 25.0 parts by weight (d/d), based on the total dry weight of the fibers and the at least one particulate calcium carbonate-containing material, wherein the at least one binder is selected from the group comprising phenol-formaldehyde resin, urea-formaldehyde resin, melamine-formaldehyde resin, melamine-urea-formaldehyde resin, urea-melamine-formaldehyde resin, urea-melamine-phenol-formaldehyde resin (UMPF), epoxy resin, methylene diphenyl diisocyanate resin, polyurethane resin, polyamide-epichlorhydrin resins, latex-based binders, lignin-based binders, starch-based binder, tannin-based binders, soya-based binder, carboxymethylcellulose-based binders and mixtures thereof, and d) at least one wax in an amount from 0 to 5.0 parts by weight (d/d), based on the total dry weight of the fibers and the at least one particulate calcium carbonate-containing material, wherein the sum of the amount of the fibers and the at least one particulate calcium carbonate-containing material is 100.0 parts by weight (d/d), based on the total dry weight of the fibers and the at least one particulate calcium carbonate-containing material and wherein the fibers originate from softwood tree species, hardwood tree species, non-wood fiber plants and mixtures thereof. a) fibers in an amount from 50.0 to 99.0 parts by weight (d/d), based on the total dry weight of the fibers and the at least one particulate calcium carbonate-containing material, wherein the fibers in an amount of i) 0 to 20.0 wt.-%, based on the total amount of dry fibers, are of a size which is fractioned at a mesh sieve width of 0.05 mm, ii) 50.0 to 90.0 wt.-%, based on the total amount of dry fibers, are of a size which is fractioned at a mesh sieve width of 1.0 mm, and iii) 70.0 to 100.0 wt.-%, based on the total amount of dry fibers, are of a size which is fractioned at a mesh sieve width of 3.0 mm, as determined by sieve analysis, i) 0 to 20.0 wt.-%, based on the total amount of dry fibers, are of a size which is fractioned at a mesh sieve width of 0.05 mm, ii) 50.0 to 90.0 wt.-%, based on the total amount of dry fibers, are of a size which is fractioned at a mesh sieve width of 1.0 mm, and iii) 70.0 to 100.0 wt.-%, based on the total amount of dry fibers, are of a size which is fractioned at a mesh sieve width of 3.0 mm, as determined by sieve analysis, b) at least one particulate calcium carbonate-containing material in an amount from 1.0 to 50.0 parts by weight (d/d), based on the total dry weight of the fibers and the at least one particulate calcium carbonate-containing material, the at least one particulate calcium carbonate-containing material having a weight median particle size d 50 of 0.5 to 150.0 μm, and additionally c) at least one binder in an amount from 0.05 to 25.0 parts by weight (d/d), based on the total dry weight of the fibers and the at least one particulate calcium carbonate-containing material, wherein the at least one binder is selected from the group comprising phenol-formaldehyde resin, urea-formaldehyde resin, melamine-formaldehyde resin, melamine-urea-formaldehyde resin, urea-melamine-formaldehyde resin, urea-melamine-phenol-formaldehyde resin (UMPF), epoxy resin, methylene diphenyl diisocyanate resin, polyurethane resin, polyamide-epichlorhydrin resins, latex-based binders, lignin-based binders, starch-based binder, tannin-based binders, soya-based binder, carboxymethylcellulose-based binders and mixtures thereof, and d) at least one wax in an amount from 0 to 5.0 parts by weight (d/d), based on the total dry weight of the fibers and the at least one particulate calcium carbonate-containing material,