The Schluter®-KERDI-TUBKIT is designed to create a fully waterproof and vapor-tight
enclosure for tiled bathtub surrounds. The TUBKIT contains all the components
necessary to prepare your bathtub surround for tile, in one convenient package.
Let’s take a look at what’s inside. A roll of KERDI waterproofing membrane
is included, which is used to protect walls from moisture penetration.
You will also find KERDI-BAND waterproofing strips, to seal between the wall and
bathtub and all seams and connections. A KERDI-SEAL-PS pipe seal and a KERDI-SEAL-MV
mixing valve seal are included. These are used to seal pipe protrusions and protect
moisture-sensitive solid backing panels. And finally, KERDI-FIX, a sealing and bonding
compound used to connect the KERDI-BAND to the bathtub.
Always refer to the Schluter®-Shower Installation Handbook, which provides specific installation
requirements and instructions. Here’s how to install the kit.
The bathtub has already been installed, followed by the solid backing. In this application,
gypsum board is used on the walls, although other solid backing panels,
such as tile backerboards, may be used instead. The solid backing has been installed flush
with the tub lip of the tub deck. We will demonstrate how to address
where the solid backing is installed over the flange later in this video.
After peeling back the protective plastic, painter’s tape is placed on
the tub deck to protect it from the subsequent sealant application.
Wipe down the walls with a damp sponge to remove any dust or other debris.
For particularly dry and porous substrates it is recommended to wet the substrate first,
in order to help prevent premature drying or skinning of the thin-set mortar.
We’ll be using Schluter-KERDI-BAND waterproofing strips in conjunction with KERDI-FIX and thin-set
mortar to address the connection between the bathtub platform and the gypsum board.
Measure and cut sections of KERDI-BAND.
Apply KERDI-FIX to the tub flange and spread using a notched trowel.
The membrane is bonded to the walls using any of our Schluter Thin Set mortars
…(PAUSE)..or an unmodified thin-set mortar.
The mortar is mixed to a fairly fluid consistency, but still able to hold a notch.
A 1/4 inch x 3/16 inch V-notched trowel or the Schluter-KERDI-TROWEL, which features
a 1/8 inch x 1/8 inch square-notched design, is used to apply the mortar.
Apply a thin layer of mortar to the gypsum board with the flat side of the trowel to produce solid
contact with the surface and then comb additional mortar using the notched side of the trowel.
Embed the KERDI-BAND in the thin-set mortar and KERDI-FIX using the flat side of the trowel
or a drywall finishing knife to ensure full coverage and remove air pockets.
Continue application of the KERDI-BAND at all wall-to-tub junctions.
If the solid backing is installed over the tub flange, leave a ¼” gap between the board
and the tub deck. The KERDI-BAND is installed in a similar manner.
In this case, simply fill the 1/4 inch wide gap completely between the solid backing and tub
with KERDI-FIX or other suitable sealant. Continue the process as shown previously.
Apply any of our Schluter® Thin Set Mortars or an
unmodified thin-set mortar to the walls where the KERDI-BAND will be placed.
Embed the KERDI-BAND in the thin-set mortar and KERDI-FIX.
The next step is to install the KERDI waterproofing membrane over the walls.
Wipe down the walls with a damp sponge to remove any dust or other debris.
For particularly dry and porous substrates it is recommended to wet the substrate first,
in order to help prevent premature drying or skinning of the thin-set mortar.
Apply a thin layer of thin-set mortar to the wall with the flat side of the trowel to produce solid
contact with the surface and then comb additional mortar using the notched side of the trowel.
Embed the KERDI membrane into the thin-set mortar to ensure full coverage and remove air pockets.
Overlap the previously installed KERDI-BAND by 2 inches for a waterproof connection.
The KERDI membrane application is continued on adjacent walls.
Waterproof integrity is maintained at joints using a 2 inch wide overlap
in conjunction with either a Schluter thin-set mortar or an unmodified thin-set mortar.
For example, KERDI sheets may be joined using 2 inch wide lap seams.
Alternatively, KERDI sheets may be butted
and covered with KERDI-BAND centered over the joint.
Lap seams are demonstrated on the plumbing wall and back wall of the bathtub surround.
A KERDI-BAND seam is demonstrated at the inside wall corner
between the back wall and the side wall.
Apply thin-set mortar to the area where the KERDI-BAND is to be installed.
KERDI-BAND may be creased prior to installation to help maintain tight corners and make
subsequent tile setting as easy as possible. Embed the KERDI-BAND into the thin-set mortar.
Since KERDI-BAND is one-half the thickness of the KERDI membrane, build-up at seams
is minimized using this method. Next, we’ll install the KERDI-SEALS.
Apply thin-set mortar to the areas where the Schluter-KERDI-SEAL prefabricated
waterproofing accessories are to be installed. Place the seals and embed them into the mortar.
Schluter-KERDI-SEAL-MV is used to protect moisture-sensitive solid backing
such as gypsum board, at the mixing valve
Schluter-KERDI-SEAL-PS is used to seal protrusions through the
KERDI membrane at the showerhead and tub spout.
As an alternative, KERDI-FIX or other suitable sealant can be used in these areas.
Once the entire assembly is covered with the KERDI membrane, including seams,
corners, and protrusions, the assembly is waterproof, vapor-tight, and ready for tile.
The KERDI-TUBKIT installation is now complete.
If tile is to be set on floors adjacent to the bathtub, we strongly recommend use of
the Schluter-DITRA or Schluter-DITRA-HEAT uncoupling and waterproofing membranes.
Leave a 1/4 inch wide gap between the DITRA and the bathtub apron.
DITRA can be sealed to the bathtub surround to provide comprehensive waterproofing in
the bathroom. Place painter’s
tape to protect the face of the tub. Remove any thin-set mortar from the gap
between the DITRA and the tub. A 1/4 inch backer rod or similar may be used to keep the joint
clean during thin-set mortar application and removed prior to the KERDI-FIX application.
Completely fill the gap between the DITRA and tub with Schluter-KERDI-FIX
or other suitable sealant. Fill the cavities in the DITRA
adjacent to the bathtub with thin-set mortar and then comb additional thin-set on top.
Apply KERDI-BAND to the joint.
Embed the banding in the thin-set mortar and KERDI-FIX using the flat side of the trowel
or a drywall finishing knife to ensure full coverage and remove air pockets.
The DITRA installation and waterproofing application is now complete.
Tile can be set immediately over the KERDI-TUBKIT and the DITRA.
Typically, sealant is used to fill the joints between the tile and the bathtub
to help prevent cracks or other damage from the tile abutting a restraining surface. The
sealant can become unhygienic and will need to be replaced over time. One solution to avoid this is
to use the Schluter®-DILEX-BWA perimeter movement joint between the tile and the bathtub instead of
sealant. The profile is installed simply with thin-set mortar in conjunction with the tile.
The profile is easy to clean and matches common grout joint colors to integrate seamlessly into
the finished tile application. For complete installation instructions, please refer to our
“How to Install Schluter®-DILEX-BWA Movement Joint Profile video.”
The Schluter®-KERDI-TUBKIT eliminates leaks, reduces efflorescence and mold
growth in the system, and dramatically reduces installation time to ensure success
and makes waterproofing a bathtub surround easier than ever.
If you still have questions, please contact our Customer Support Specialists. For more information
on Schluter products, visit schluter.com or check out our YouTube channel to view our videos!