Schluter®-KERDI-DRAIN-F is a floor drain with a flat and narrow bonding flange
available in both polypropylene and stainless steel.
The drain is ideal as a secondary floor drain in bathrooms, laundry rooms, and basements.
Since the drain casing is flat and does not feature a recessed section,
it is installed directly in the floor without needing to notch out the subfloor.
The smaller size of the drain allows the drain to be installed in corners and against walls.
The KERDI-DRAIN-F flange measures 1/8” thick and is designed to sit
flush with DITRA and DITRA-HEAT membranes, providing an even surface for setting tile.
The membrane can be installed before or after the flange.
And with an integrated KERDI collar, a waterproof connection to Schluter®-DITRA is simple.
Let’s take a look at the parts and pieces associated with the KERDI-DRAIN-F.
There are two versions of the drain flange available.
A polypropylene version that comes with both an ABS and PVC coupler.
and a stainless steel version which is available with either a threaded or no-hub outlet.
Couplers are not supplied with the stainless steel drain flange.
You will receive a construction cover to protect the KERDI collar during your installation….
And finally, a vertical height adjustment collar to set your grate
to the proper height when setting tile. KERDI-DRAIN-F can be used with our standard
KERDI-DRAIN grates, where there are a large variety of designs and finishes available.
First things first, always refer to the Schluter DITRA installation Handbook for all of the
requirements for your particular installation. A trap primer should be installed in low use
drain applications to prevent drying out of the trap.
Always refer to your local plumbing codes. We’ll start by demonstrating the installation
of the polypropylene flange as an overflow drain in a laundry room.
We’ll demonstrate the installation of the Stainless Steel flange later in this video.
We will be installing the drain in the corner. Locate the correct position for the drain flange.
The location should be based on the position of your plumbing as well as tile layout.
It is important to consider your profiles and any wall tile you may be installing as well.
Cut a 4” hole in the substrate for the drain outlet and coupling to the waste line
using the template provided. Limit the diameter of the hole
to a maximum of 4-1/4" to ensure proper support of the tile assembly.
A larger hole can lead to lack of support and damage.
Make sure the substrate is flat, level and clean and free of debris
prior to installation of the flange. Since our flange is being set in the corner,
we will need to cut the KERDI collar such that it fits tight into the corner once installed.
It may be convenient to use a small piece of painter’s tape
to keep the KERDI collar in place during the next steps of installation.
Next apply thread sealing compound or tape to the bonding flange, then connect the appropriate
adaptor. We are using PVC in this example, but the process for using ABS is the same.
Apply thin-set mortar up to the opening in the substrate
using the appropriate trowel for the membrane to be installed. Apply thin-set using the flat side
of the trowel and then apply additional thin-set mortar using the notched side of the trowel.
In this case we will be installing the DITRA membrane, so we are using the DITRA trowel.
Solidly embed the bonding flange in the mortar… and check for level.
If you do not have access to the plumbing from below, please refer to our
“No Access Plumbing Demonstration with Schluter®-KERDI-DRAIN” video.
If the drain is installed well in advance of the DITRA membrane, the construction cover
is used to protect the flange and KERDI from any damage that may happen on the work site.
The cover can be cut to fit in instances where the flange sits tight to the wall.
The construction cover is secured into place until the next steps of installation resume.
In this example we will be installing DITRA directly after the KERDI-DRAIN-F
so the construction cover will be set aside.
Prepare the DITRA for installation. Cut a hole in the membrane using the
template provided. The cut out should be a 5-1/4” square for the polypropylene flange.
Install the membrane with thin-set mortar up to the bonding flange
and along the remainder of the floor area. For step by step details on how to install
Schluter® membranes, please refer to our YouTube channel.
Apply thin-set mortar to the area where the KERDI collar is to be installed
using any of our Schluter® thin-set mortars… or an unmodified thin-set mortar.
Comb additional mortar using a 1/4" x 3/16" V-notched trowel
or the Schluter®-KERDI trowel, which features a 1/8" x 1/8" square-notched design.
Unfold the KERDI collar and solidly embed into the mortar with the flat side of the trowel
to ensure full coverage and remove air pockets.
In order to maintain a 2 inch overlap in the corner,
we will install a KERDI-KERECK inside corner in this area.
The corner is installed in the same manner as the KERDI collar as shown previously.
Continue the waterproofing application using Schluter®- KERDI-BAND at floor
to wall transitions and DITRA seams. With the KERDI collar,
the KERDI-BAND achieves a 2 inch overlap without running all the way in to the corner.
As you can see, the polypropylene drain flange is flush with the floor.
The installation and waterproofing are now complete.
Next we will demonstrate the installation of the stainless steel drain flange.
A 4” drain opening has already been prepared in the substrate for the drain outlet and coupling
to the waste line using the template provided. The opening should not exceed 4-1/4” in order
maintain proper support of the drain flange. The membrane will be installed first.
Install the DITRA as previously shown.
Using the template provided, cut a hole in the membrane for the drain flange.
The hole in the membrane should not exceed a 5-3/4” circle for the stainless-steel flanges.
Connect a no-hub coupler to the drain flange. A shielded coupler may be required in certain
applications. Again, make sure to refer to your local plumbing codes.
Apply thin-set mortar to the area where the KERDI-DRAIN-F is to be installed.
Embed the KERDI-DRAIN-F in to the thin-set mortar.
Install the KERDI collar as shown previously.
Check the drain for level.
Continue the waterproofing application using Schluter®- KERDI-BAND
at floor to wall transitions and DITRA seams. As you can see, the Stainless Steel drain flange
is flush with the floor. The installation and waterproofing are now complete.
Finally, we will install the grate assembly within the KERDI-DRAIN-F flange. This demonstration will
be done in a wall application. The grate assembly is installed
in conjunction with the tile. The process for installation is
the same with both the polypropylene and the stainless steel flanges.
Set the tile up to where the grate will be installed.
Snap the vertical height adjustment collar on to the grate frame.
Then, apply thin-set mortar to the underside of the grate frame.
This will ensure support of the grate assembly.
Place the grate assembly in to the drain …and press flush with the tile surface.
It is important to remove all excess setting material immediately from the grate assembly.
The grate assembly installation is now complete. The KERDI-DRAIN-F is ideal as a secondary floor
drain in various applications and provides a simple and secure connection to the floor
with it’s flat design and integrated waterproofing.