The paper describes the solutions of the building materials heat conduction problems - heating source power and size definition based on temperature measurements on a material surface and on layers, heating source characteristics and surface temperature identification by temperature measurements on a treated area. The basic problem of the building concrete block heating by mobile Gauss type thermal source are addressed. As a result there are given formulae for an estimation of the plasmatron useful power and maximal temperature on the depth z ≥ 1 mm with accuracy enough for a practical appliance. Also values of the main technological parameters during the treatment are recommended and the technology of concrete block finish is shown.