Method for applying a fiber-containing building material, especially by means of 3D printing, comprising the steps of - providing a hydrous mineral binder composition, at least one aqueous accelerator and fibers, - feeding the hydrous mineral binder composition, especially by means of a pump, to a continuous mixer comprising • a drive , • a mixing region comprising at least one inlet and at least one dynamic mixing element, where the dynamic mixing element comprises a stirring shaft having stirring elements , the stirring elements taking the form of pegs, and a distance between adjacent stirring elements being at least 60%, more preferably at least 80%, of the length of the longest fibers and • a conveying region connected to the mixing region and comprising at least one conveying device and an outlet , the hydrous mineral binder composition being conveyed through the at least one inlet into the mixing region , - feeding the fibers into the mixing region of the continuous mixer , - feeding the at least one aqueous accelerator for the setting of the hydrous mineral binder composition into the mixing region of the continuous mixer , - mixing the at least one aqueous accelerator with the hydrous mineral binder composition and the fibers in the mixing region of the continuous mixer to give an accelerated fiber-containing mineral binder composition, - conveying the accelerated fiber-containing mineral binder composition by means of the conveying device to the outlet , and - applying the accelerated fiber-containing mineral binder composition, in particular layer by layer by way of a movable printing head. - providing a hydrous mineral binder composition, at least one aqueous accelerator and fibers, - feeding the hydrous mineral binder composition, especially by means of a pump, to a continuous mixer comprising • a drive , • a mixing region comprising at least one inlet and at least one dynamic mixing element, where the dynamic mixing element comprises a stirring shaft having stirring elements , the stirring elements taking the form of pegs, and a distance between adjacent stirring elements being at least 60%, more preferably at least 80%, of the length of the longest fibers and • a conveying region connected to the mixing region and comprising at least one conveying device and an outlet , the hydrous mineral binder composition being conveyed through the at least one inlet into the mixing region , • a drive , • a mixing region comprising at least one inlet and at least one dynamic mixing element, where the dynamic mixing element comprises a stirring shaft having stirring elements , the stirring elements taking the form of pegs, and a distance between adjacent stirring elements being at least 60%, more preferably at least 80%, of the length of the longest fibers and • a conveying region connected to the mixing region and comprising at least one conveying device and an outlet , - feeding the fibers into the mixing region of the continuous mixer , - feeding the at least one aqueous accelerator for the setting of the hydrous mineral binder composition into the mixing region of the continuous mixer , - mixing the at least one aqueous accelerator with the hydrous mineral binder composition and the fibers in the mixing region of the continuous mixer to give an accelerated fiber-containing mineral binder composition, - conveying the accelerated fiber-containing mineral binder composition by means of the conveying device to the outlet , and - applying the accelerated fiber-containing mineral binder composition, in particular layer by layer by way of a movable printing head. <EOS>