Is the Kerdi-Seal Pipe Seal worth it?

If you are already building a Kerdi shower, yes. It is a few dollars and gives a factory-made, watertight collar around a pipe instead of a hand-cut membrane patch. It has no use outside the Kerdi system.

What pipe size does it fit?

The gasket opening is 3/4 inch, model KMS172/20. Check your pipe diameter before ordering; Schluter makes other sizes for different penetrations.

The membrane flange is embedded in thin-set over the Kerdi membrane or Kerdi-Board, and the rubber gasket seals around the pipe. Tile goes over it, so keep the 4-mil thickness in mind for lippage.

Does it work with mosaic tile?

Yes. Schluter lists it for mosaic, standard and field tile. The thin 4-mil profile helps it sit flat under small tiles.

One pipe seal, 7.25 by 7.25 inches overall. Thin-set and the pipe are not included.

The best new price was $7.97 at Home Depot as of November 4, 2026, with 7 stores listing it new. On a part this small, shipping usually matters more than a dollar of price difference.