As a salesperson chances are good you have heard (or asked) the question: What’s the difference between ceramic and porcelain? The question itself is confusing. It’s like asking what the difference is between apples and Granny Smiths. The textbook definition of porcelain is any ceramic tile that achieves .5% water absorption or less. In fact, porcelain is only one of four different ceramic tile bodies and each one is made for a very specific purpose. Each of the four types of ceramic tile is classified by their water absorption (WA) percentage and each one is the best specification for its intended area.

Non-vitreous
WA at 7% and above is best used in any interior wall application. Even in wet areas this material is absolutely perfect, as long as it’s glazed, which a majority of this material is. Wall tile’s porosity makes it easy to bond with common mortars and adhesives keeping installation costs low. Since this product is not overly dense it can be fired at lower temperatures allowing for the broadest ranges of glaze colors and finishes.

Semi-vitreous
WA at 7% to 3% is for any interior dry floor area, accounting for the lion’s share of all specifications by area. There is a range here because it is such a broad category and manufacturers try to give us as many options as possible. The rule of thumb when selecting tile is as traffic levels go up, porosity should go down.

Vitreous
WA of 3% to .5% is for exterior applications or occasionally wet interiors, an area that may get wet but will always have opportunity to dry fully, like a laundry room that could flood or a basement on a slab with heavy condensation. If you are selecting a material for outdoors you may need to ensure that it has been tested for frost resistance depending on the weather in your area.

Impervious
Anything at or below .5% is porcelain. This is the densest material in the industry and is designed for the most demanding environments like submerged areas and wheeled traffic. Submerged can be anything from a fountain basin to a shower base since neither ever dries out for an appreciable amount of time. Porcelain must be fired at the hottest heats, somewhat limiting glazing options. Installation costs are usually higher due to more expensive, latex-modified thinsets and difficulty cutting.

On the other hand, porcelain is the densest material in the ceramic family and will survive in almost any environment, so it’s never the wrong specification. But if porcelain is the only thing looked at there are unnecessary limitations on design options.