[en] The Dutch Research and Development Program into the radiation safety of houses and related radioecological problems is reviewed. Monitoring and registration of background radiation radon concentration in our daily living environment, partly originating from certain building materials, should occur. Radiological stock-taking of materials and construction elements for buildings has to be investigated. Concentration of radionuclides should be determined in samples. Radiological studies related to the emission from coal-fired plants and leaching of fly ash used in building materials have been started. The measurements with temporary integrating passive RN-dosimeters revealed values for exhalation rates, the average ventilation rate and the resulting RN-concentration. The average radiation exposure of the lungs can be calculated from a general risk analysis. (Auth.)