Installation Guide
The waterproofing is carried to the height of the showerhead (at minimum). KERDI or KERDI-BOARD application on ceiling is optional for bathtub surrounds.
Bathtub surround
Please refer to Schluter
®
-Systems' installation videos in addition to reading the instructions below.
INSTALLATION
Clean any dust or other debris from the 
surface of the solid backing. Dampen 
particularly dry and porous substrates in 
order to help prevent premature drying or 
skinning of the thin-set mortar.
1
Place painter’s tape to protect the tub deck. 
Apply Schluter SET
®
, ALL-SET
®
, FAST-SET
®
, 
or unmodified thin-set mortar to the solid 
backing using a 1/4" x 3/16" (6 mm x 
5 mm) V-notched trowel or the KERDI-
TROWEL. Completely fill the 1/4" (6 mm)-
wide gap between the solid backing and 
tub with KERDI-FIX or other suitable sealant.  
Note: When the solid backing is installed 
above the tub flange, apply KERDI-FIX to 
the tub flange and spread using a small 
notched trowel.
2
Apply KERDI-BAND waterproofing strips or 
5" (125 mm)-wide cut sections of KERDI 
waterproofing membrane. Solidly embed the 
membrane in the mortar and KERDI-FIX to 
ensure full coverage and remove air pockets.
3
Schluter
®
-KERDI over solid backing
Apply Schluter SET
®
, ALL-SET
®
, FAST-
SET
®
, or unmodified thin-set mortar to 
the solid backing and previously applied  
KERDI-BAND. Embed the KERDI in the  
thin-set mortar and work the membrane onto 
the entire surface to ensure full coverage and 
remove air pockets.
4
Seams in the membrane are constructed 
by overlapping the edges of KERDI by  
2" (50 mm) or by abutting adjacent sheets of 
KERDI and installing KERDI-BAND, centered 
over the joint. 
5
Any penetrations through the KERDI 
membrane (e.g., mixing valve, shower head, 
etc.) must be sealed with KERDI-SEAL-PS/-
MV, KERDI-FIX, or other suitable sealant.
6
Seal connections to knee walls using KERDI-
KERECK-F preformed corners and Schluter 
SET
®
, ALL-SET
®
, FAST-SET
®
, or unmodified 
thin-set mortar.
7
Once the entire membrane, including seams, 
corners, and knee walls have been completely 
bonded and, therefore, waterproofed, 
the assembly is ready to be tiled. For tile 
installation instructions, see page 33.
8
The thin-set mortar used for bonding KERDI to walls and ceilings must be appropriate for the substrate and must penetrate and engage the membrane 
fleece. The mortar must be mixed to a fairly fluid consistency, but still able to hold a notch.
KERDI-SEAL-PS/-MV KERDI-FIX
Note: See page 23 for KERDI-BOARD-SN 
shower niche installation instructions. 
36  INSTALLATION — Bathtub surround — Schluter
®
-KERDI










