if the sink is a preformed part of the marble and not separate, then no you cant really tile over it and have a nice finish at the preformed sink. Most big box home centers will have preformed batchroom coutnertops/sinks to choose from. Or you could remove the preformed counterttop/siink, make a new one out of plywood, isntall your backer board and tile, and installa a new sink.

Now, if the sink and the coutnertop are two separate products, you can remove the sink, install backe4rboard and tile up to the hole, grout it, then re-install the sink and caulk it.

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There are two ways to do any job.

The right way and the wrong way.

Do it right everytime.

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