Building materials are one of the potential sources of indoor radioactivity because of the naturally occuring radionuclides in them. Exposure to indoor ionizing radiation, like gamma radiation, results in critical health challenges. This work was designed to assess the indoor gamma dose rate level following the renovations of offices of lecturers in Faculty of Science, University of Ibadan using RDS-30 Survey meter. Measurements were made at 110 locations after renovations and in some selected departments before renovations. The measured indoor gamma dose rate varied from 0.07μSv/h to 0.25μSv/h with an average mean of 0.132 ±0.03μSv/h after renovations and varied from 0.08μSv/h to 0.15μSv/h with an average mean of 0.112
±0.01μSv/h before renovations. The results obtained showed that there is slight difference, though insignificant, in the indoor gamma dose rate level which indicated a variation with change or introduction of some building materials used for renovation. The average indoor gamma dose rate obtained was below 1mSv/yr recommended by the International Commission on Radiological Protection (ICRP), hence, the lecturers are radiologically safe in their offices.
