KERDI-KERS is a pre-formed, ready-to-install corner piece for creating waterproof inside corners in KERDI shower installations. Instead of cutting and folding KERDI-BAND into a 90° corner (which takes practice and often leaves wrinkles), you press this pre-shaped piece into wet thin-set and the corner is sealed — perfectly formed, no wrinkles, no gaps.

Inside corners are the most common point of waterproofing failure in showers. Water pools there, movement stress concentrates there, and hand-folded band is hardest to get right there. KERDI-KERS solves that by giving you a factory-formed piece that fits exactly.

Where to use it

• Wall-to-wall inside corners: Where two shower walls meet at 90°
• Wall-to-floor corners: Where the shower wall meets the floor/pan
• Wall-to-ceiling corners: In steam shower enclosures
• Curb-to-wall joints: Where the shower curb meets the wall

KERDI-KERS vs. KERDI-KERECK — what's the difference?

• KERDI-KERS: Smaller, simpler pre-formed corner — quick and universal
• KERDI-KERECK: Larger, flat-flanged corner piece — more coverage area, available in inside and outside corner versions, and in bench corner configurations
• Both create waterproof corners. KERDI-KERS is faster for simple corners. KERDI-KERECK provides more overlap for critical waterproofing areas.

Installation

• Apply thin-set mortar to the corner area
• Press KERDI-KERS into the wet mortar, embedding the flanges fully
• Smooth out any air pockets with a margin trowel or float
• Overlap adjacent KERDI membrane or KERDI-BAND strips by at least 2"
• Tile directly over the cured assembly

Specs

• Material: KERDI waterproofing membrane (same material as KERDI sheet)
• Shape: Pre-formed 90° inside corner
• Bond: Set in thin-set mortar (Schluter SET, ALL-SET, or FAST-SET)

Pairs with

• KERDI waterproofing membrane
• KERDI-BAND sealing strips
• KERDI-KERECK inside/outside corners (for larger coverage)
• Schluter SET or ALL-SET mortar