Abstract: The invention relates to a method and a device for providing at construction sites paste-like building materials, especially mortar, being delivered in a fixedly pre-determined basic consistency. A conveying and mixing pump with an additional water supply opening is provided below the storage container for the paste-like building material. By means of the water supply opening, additional water is mixed with the mortar in order to produce the desired mortar consistency. For this purpose, a mixing portion having hedgehog-type mixing elements is provided.