Abstract: A coolable housing wall for hot gas fluid flow engines, especially for a gas turbine of the air jet type, is provided on its radially inwardly facing surface with a carrier for a single cover layer forming a running-in coating. The cover layer is applied by thermal spraying to form a ceramic coating having a high heat and corrosion resistance. The single cover layer has a substantially uniform thickness and projects radially inwardly from the carrier, preferably by forming ridges facing the blade tips of a rotor in the housing. Such cover layer also has a high erosion resistance.