The integrity of a KERDI-waterproofed shower rests entirely on the quality of the membrane seams. Because the system is sheet-applied, the joints where membrane pieces meet must be perfectly sealed. To achieve this, each sheet must overlap the adjacent sheet by a minimum of 2 inches. This overlap provides the necessary contact area for the thin-set mortar to form a strong, permanent, and monolithic bond. Applying the thin-set correctly is critical. The mortar must be spread evenly, and the membrane must be pressed into it using the flat side of a trowel to force out air bubbles and ensure the membrane is fully embedded in the mortar. When properly executed, this process links all sheets into a single, seamless, waterproof envelope. Do not attempt to 'butt' the joints; the specified 2-inch overlap is essential to prevent water from wicking behind the membrane. Always use the mortar recommended by the manufacturer to ensure the bond strength matches the system's requirements.
Key considerations
- how to join KERDI seams
- KERDI membrane overlapping
- waterproofing shower seams
- Seams
- Waterproofing
- Installation