09/05/2026
Kerdi patch failing? Your overlap is too small.
Everyone patches a hole in Kerdi membrane the same way —
cut a piece slightly bigger than the hole, thinset it down,
call it waterproof.
It isn't. Schluter's spec is 2" of overlap onto sound
membrane on every side. Not the hole. Every side.
Patch a 3" hole and you need a 7" piece minimum.
Unmodified thinset, full coverage, no voids at the seam.
Flood test before you tile.
Comment FIX and I'll send you the Kerdi tear repair
breakdown — straight from Schluter's documentation.