Porcelain vs ceramic tile: which to choose for a bathroom floor or shower

In the porcelain vs ceramic tile decision, porcelain is a defined subset of ceramic with very low water absorption, but that alone does not make a tile right for a wet floor. For bathroom floors and shower floors, the specific tile's wet slip rating and declared use matter more than the name on the box. Neither type waterproofs a shower by itself.

What actually separates porcelain from ceramic

Porcelain is not a marketing tier above ceramic. It is a tile classification. Under ANSI A137.1, porcelain is ceramic tile with a water absorption of 0.5% or less, measured by a standard laboratory test. A tile that absorbs more than that is simply ceramic, even if the showroom calls it something else.

That is why the absorption figure on the spec sheet is more useful than the label. If a product does not state it, ask the supplier for the technical data sheet before you order.

A note on the standards used here

ANSI and the Tile Council of North America (TCNA) are US-based bodies, and most figures in this article come from their published material, so treat it as general information rather than Ontario-specific requirements. In Canada, the Terrazzo, Tile and Marble Association of Canada (TTMAC) publishes a tile installation specification guide (09 30 00) and a Tile Installer Technical Handbook. Ask your installer which references they build to, and confirm any local requirements, including those for shower construction, with your municipal building department.

Bathroom floors: start with slip resistance

Water absorption tells you how dense the tile body is. It says very little about how the surface feels under a wet foot. For that, the tile industry uses the dynamic coefficient of friction (DCOF) test in ANSI A326.3. According to the Tile Council of North America, the standard sorts products into five use categories. The Interior, Wet category calls for a wet DCOF of at least 0.42 or a manufacturer declaration.

Finish and surface texture affect that number, and a tile's name does not. One manufacturer's guidance notes that tile testing below 0.42 should only be installed where it stays dry and is cleaned with appropriate safety procedures. A glossy or polished tile on a bathroom floor that is regularly wet is therefore worth questioning unless the manufacturer declares it suitable.

Treat the number as a comparison tool, not a guarantee. TCNA's DCOF FAQ explains that DCOF and real-world slip resistance are not the same thing. Look at the texture in person, and use the published wet DCOF and use category as a starting filter.

Shower floors: a declared use and a higher wet DCOF

A shower floor is wet, soapy and often walked on barefoot. The TCNA FAQ lists an Interior, Wet Plus category that is declared by the manufacturer rather than set by a test limit. One manufacturer describes products in that category as having an elevated wet DCOF, enhanced texture or frequent grout joints, with shower floors listed as a possible use.

The category has no mandatory number, but it does have guidance. A summary of the A326.3 informative note says that, absent a different manufacturer declaration, flooring in this category should have a wet DCOF of at least 0.50. Treat that as generally accepted guidance, not a hard requirement, and not a substitute for texture and drainage.

Ask the supplier whether the specific tile is declared suitable for shower floors, and ask for that in writing. If they cannot say, choose a different tile.

Shower walls: the tile is not the waterproofing

Walls do not take foot traffic, so floor slip ratings are not the main concern there. Check the manufacturer's data sheet to confirm the specific tile is suitable for wall use in a wet area. Choosing porcelain for both floor and walls can then come down to look and budget.

Whichever you choose, the tile and grout are not what keeps water out of the wall. TCNA's FAQ states that grout joints are not waterproof and that wet areas depend on the installation method and substrate. Our guide to what goes behind the shower tile covers that layer in detail.

Common mistakes when choosing

• Choosing by name alone. Compare absorption, wet DCOF and declared uses on the data sheet instead.
• Putting polished tile on a wet floor. It looks clean in the showroom, but check its wet DCOF and declared use first.
• Assuming dense tile replaces a membrane. Low absorption does not make grout lines watertight.
• Comparing price by category alone. Get pricing for the specific tiles you are considering, plus setting materials and labour.

A practical way to decide

Start with the absorption figure to see whether a tile is porcelain or ceramic. Then check the wet DCOF and use category for the room, and for a shower floor look for a manufacturer declaration that covers that use. For walls, confirm the data sheet lists the tile for wet-area wall use.

If you are planning a new bathroom and want help matching tile to the layout and the waterproofing system, see our bathroom renovation services.