This research reports the annual effective dose of dwellers based on the finding of natural radioactivity concentrations in
Malaysian tiles. A total of 30 tiles samples obtained from the manufacturer or bought directly from local hardware store.
Natural radioactivity was analyzed using gamma spectrometry system for 12 h counting times. The activity concentration
of 226Ra, 232Th, and 40K in the analyzed samples ranged from 37.50 – 158.05 Bq kg-1, 42.22 – 80.19 Bq kg-1 and 349.46 –
750.18 Bq kg-1, respectively. The determined radium equivalent activity was below than the recommended limit of 370
Bq kg-1. The external dose received by dwellers due to natural radionuclides in tiles were projected for 1, 5, 10, 20 and
50 years through six exposure pathways using Resrad-build computer code. The results showed that the annual effective
dose received by dwellers increased for the investigated timelines but still lower than the annual recommended limit of
1500 µSv. The simulation result also indicates that radon gas was the primary radiation exposure which contributes
80-94 % from the total radiation exposure to dwellers.