The dose of radiation received in a natural environment may be increased in some buildings because of the building materials. It is convenient to avoid radioactive materials as far as possible in order to avoid long-term effects.
In general, construction materials made of waste or more recent formation stones, such as volcanic stones, contain larger radioactive elements: Thorium-232, radium-226 and potassium-40. Among these elements we can find granite, bassalt or concrete, to which fly ash has been added.
On the other hand, materials of organic origin such as wood, or sedimentary stone derivatives like natural gypsum or limestone sand provide low radioactivity values.
Therefore, the raw material is the main factor which states the emission of radioactivity in construction materials like bricks or tiles.