Radon exhalation from soil and ores is among the most dangerous risks for the public health care. The impact becomes even more powerful when technological enhanced naturally occurring radioactive materials (TENORM) are used for public and private building. Here, we report the realization of a down-scaled model of a building, whose construction materials contain TENORM harvested in a site in Crotone (Italy). We observe an increase of the radon activity in the model when TENORM residues are employed. These results have then been compared to a real use case. The correspondence found between the values of radon activity concentration in the model and in the use case suggests that estimating the radon concentration is an useful method to target TENORM presence inside buildings.