First of all, thanks to TS for useful sharing! It helps a lot, especially to me as a first time buyer.

Regarding hollow tiles, the site manager told me it is considered fine if the tile appear hollow at the corners. It's defect if any of the center part of the tile is hollow. He explained that a tile cannot be fully filled up with cement, or else it have no way for contraction when thermal changed which resulting the tiles to "explode". He says tiles should be 80% hollow. Is that true?

Any tips on how to check for uneven tiles? Uneven means a tile appear higher or lower than its neighbor. I expect 2'x2' porcelain tiles should be leveled with each another, as if I slide a 10 cents coin across the tiles, the coin will be able to cross the tiles without feeling anything in between, but they are not for my case. Sometimes I need to lift the coin when next tile is too high.

Thanks in advance for your kind sharing!

Hi aaronpang,

Thanks again for your kind explanation! Below I have a few follow up questions:

Does this sort of tiles brings any side effect besides sounding hollow?

Sorry I don't really understand this one, would you mind to further elaborate?

Thanks! Will get one of this today!

Again, thanks a lot for your time answering my questions