Abstract: The invention concerns a profiled building sheet of a type which has at least one side provided with outward facing studs and/or other types of profiles, the said building sheet being intended, amongst other things, to protect a building from the intrusion of water, in that the building sheet includes a layer of material which prevents water from passing through the sheet and into the building. The building sheet consists of at least two layers where at least one of these layers consists of a material which possesses the properties and/or gives the effect(s) it is desired that the building sheet shall have. The invention also concerns a procedure for producing such building sheets.