Ten blocks of HDB flats at Compassvale Link are getting their toilet floors and walls, as well as the toilet bowl, replaced.
The affected blocks are blocks 267 A and B, 268 A to D, and 269 A to D.
Residents of these blocks claimed that their toilet floors had started to collect water and were beginning to creak and sag when stepped on.
Water splashing onto the bathroom floor would be absorbed into the tiles, causing them to become spongy and unstable.
The floorboards also had a bad smell due to stagnant water that accumulated beneath them.
"You could see that the toilet floor was not that hard," said Madam Ivy Huang, 31, an affected housewife.
"And when I walked in, I could hear something like the sound of water puddles."
HDB is replacing the affected prefabricated toilets with conventional ones. Prefabricated flats are manufactured elsewhere, before being assembled on site.
Each toilet takes about 13 working days to replace. As of Aug 31 this year, about 600 toilets have been replaced.
The flats, which were built in 2004, came with a one-year Defective Liability Period (DLP).
Any builder defects reported within the one-year DLP will be rectified for free.
Although the DLP for Compassvale Link is over, residents will not have to pay for the renovation of their toilets.
Fibre-Reinforced Plastic (FRP) had been used as the material for the floor.
HDB stopped using FRP to build prefabricated toilets in 2006, two years after the Compassvale Link flats were built.
The materials used now are ferro-cement, or concrete.
Responses to the free renovation works have been mixed.
Some residents brought up the inconvenience the conversion works caused, citing the dust and noise pollution.
Miss Nellie Thor, a resident of Block 268A, said her parents did not apply for the conversion, but were still somewhat affected.
"All the renovation works (from the neighbours) made our house quite dusty," said 19-year-old Miss Thor.