Abstract: Apparatus and method for treating a material web, which has at least one nip through which the material web is guided and which is formed between a first revolving, heated surface and a second revolving surface, it being possible for the first surface to be heated to at least 120° C. and both surfaces in the nip having the same direction of movement as the material web. Good surface quality of the material web is obtained by providing a box which bounds a space through which the material web is guided, the space being arranged after the first or after the last nip in the direction of movement of the web.