A porcelain mark is a tested absorption claim
Standards call porcelain an impervious tile with water absorption of 0.5 percent or less, measured by ASTM C373. The Tile Council certification page, fetched on 2026-10-11, says products that miss that test are still advertised as porcelain. The Ceramic Tile Distributors Association and the Tile Council set up the Porcelain Tile Certification Agency so a manufacturer can prove the claim.
What the mark is for
A manufacturer who wants the mark sends the product for independent testing. If it meets the absorption criterion, the mark may go on packaging and sales material. The page describes that as a check against marketplace confusion from mislabeled tile. IPA Laboratories is named as the only PTCA-authorized lab in the United States for this program.
What the mark does not decide
The certification page is about whether the body meets the absorption number. It does not choose a floor for a wet room, and it does not describe how a particular installer sets the tile.
Source
Fetched 2026-10-11 from Tile Council porcelain certification page. The sentences above follow that page. They are not a contractor promise.
Related notes
- Tile notes index
- Porcelain means 0.5 percent water absorption or less
- DCOF is a measured slip value, not a brand name
- Floor photos
Send photos if you want another person to look at the area. This note does not set a response time.