Ed the Plumber explains the difference between undermount and tile-in kitchen sinks.

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Q: In my kitchen, I have very old tile countertops with an undermount cast-iron sink that is leaking. It looks like the best option is to replace the sink and tiles and start new. I’m looking into sinks, and my question is: What is the difference between an undermount cast-iron kitchen sink and a tile-in cast-iron sink?

A: I receive a lot of questions about older kitchen sinks, and in many cases, it is a good idea to start fresh.

Today’s undermount cast-iron sinks have a wide, flat rim and are designed to mount beneath your kitchen countertop. These sinks are best used with solid-surface and stone countertops.

If you’re planning to reinstall tile for your countertop, a tile-in cast-iron sink is a good choice. A tile-in sink is specially designed to be installed in a tile countertop. It has a square rim with a straight, flat edge that’s made to match the thickness of most tiles. Your countertop tiles butt right up to the edge of this rim. Basically, the sink is like a big tile.

Bottom line: If you plan on installing a tile kitchen countertop, a tile-in sink may be your best-laid plan.


Master contractor/plumber Ed Del Grande is known internationally as the author of the book “Ed Del Grande’s House Call,” the host of TV and Internet shows, and a LEED green associate. For more information, visit eddelgrande.com.