A coating apparatus for double-sidedly coating a porous web with a dope, includes: (i) a slot-die coating head comprising an upper lip, a lower lip and a slot between the upper lip and the lower lip, (ii) a counter element arranged opposite the lower lip across a reference plane, (iii) a slit defined between the lower lip and the counter element for passing a porous web therebetween, the slot opening up towards the slit, and (iv) a web positioning element. The web positioning element is the upper lip of the slot-die coating head. The upper lip protrudes up to the reference plane so that there is an offset between the upper lip and the lower lip, or a spacing structure on the counter element. The spacing structure protrudes up to the reference plane so that there is an offset between the spacing structure and the counter element.