Hi guys, Need advise on replacement of hollow homogenous tiles as i had replaced once b4 for my living hall,tis is the 2nd time the tiles became hollow again... Here my story goes..moved in a new premium hdb flat on 2005,abt 1yr later living hall tiles become hollow n started to pop out.Informed the HDB tech officer and got all the tiles replaced.Had a hard time cleaning up all the dirt,it was a nightmare... Until recently.i noticed 5pic of tiles became hollow again.went to see the officer again n asked him y tis problem occur again,he told me maybe it due to tiler or workers accidentally stepped on those undry cement during tat time when they just finished laying the new tiles.To save the trouble n mess again,i agreed to let HDB contractor to replace the 5 hallow tiles n asked a warranty if happen again i going to engage my own private contractor to replace the whole living hall tiles n HDB going to compensate me all the costs and expenses.When the contractor done replacing the tiles,i were shocked to see to 2 different tone of tiles.He told me it because its new tat y 2 different tone.Now another area of my living hall some tiles became hallow. Yesterday i decided to check online to see whether the HDB contractor izzit license to my shock i cant even find the company name listed so i call up HDB hotline to check,tis HDB contractor had never apply for a license b4.....called up HDB Tech officer asked him n he told me the company had register for license under another name. Anyone can kindly advise or recommend any reputable renov company.. Thanks alot!!