Installing a FloFX Drain in a Schluter Kerdi Foam Pan

Okay, so you asked for it — and now you got it! FloFX just came out with a traditional bonding flange that fits perfectly into a pre-sloped Schluter Kerdi foam tray. Yep, that means all you tile installers and DIYers who’ve been wondering if you can use a FloFX drain with a Kerdi pan — the answer is finally YES.

If you’ve followed me for a while, you know I’ve had tons of people ask, “Isaac, can I use a FloFX drain in a Kerdi preformed tray?” And my answer was always no… because the original FloFX flange was square and didn’t fit the Kerdi’s round opening.

Well, FloFX fixed that problem — and it’s awesome. So in this post, I’m going to walk you through:

• What makes this new FloFX drain design so smart

• How it compares to the original Schluter Kerdi flange

• And a full installation step-by-step so you can see how it all comes together

Let’s get into it.

🎥 Watch the Full Tutorial

Video: Installing a FloFX Drain in a Schluter Kerdi Foam Pan

Key Takeaways for Homeowners & Pros (TL;DR)

• FloFX now makes a round bonding flange that fits into Kerdi pre-sloped trays.

• The thicker adjustment ring helps prevent dips when using small tile or mosaics.

• Aggressive weep channels give better evaporation than Schluter’s small holes.

• Recessed screw holes allow for secure fastening without membrane bumps or tears.

• Mechanical mortar lock channels keep the flange solidly bonded to thinset.

• Comes as a full kit — flange, adjustment ring, and grate carrier all included.

• Made in the USA by a small business that supports pros and DIYers alike.

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Tools & Materials You’ll Need

• FloFX bonding flange with grate carrier & adjustment ring

• Kerdi pre-sloped foam tray

• Utility knife or rock knife (for trimming the tray)

• Modified thinset mortar

• ½" x ½" notch trowel (for pan installation)

• ¼" x 3/16" V-notch trowel (for sheet membrane and corners)

• ABS pipe cement

• Screws (stainless recommended)

• Level, margin trowel, and sponge

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Understanding the FloFX vs. Kerdi Bonding Flanges

Traditional Schluter Kerdi Bonding Flange

Schluter’s Kerdi flange has been the go-to for years. It’s lightweight, smooth ABS plastic with small weep holes, and it relies mostly on thinset adhesion to stay in place. It works fine — but it’s got some drawbacks:

• The adjustment ring is thin, which means when you use small tiles or mosaics, the grate area tends to dip below the tile surface.

• The weep holes are tiny, so evaporation around the flange isn’t as effective.

• The mounting holes are too small for standard screws — and the heads stick up, which can damage your membrane.

• The ABS plastic is slick, meaning thinset doesn’t bond to it very well.

Now let’s talk about how FloFX improved every one of those things.

FloFX Bonding Flange Improvements

At 00:01:33, I show one of the biggest upgrades right away — the adjustment ring.

1. Thicker Adjustment Ring

FloFX made theirs thicker, so it sits flush with your tile surface. That means no more dips when setting mosaics or small tile. It’s the perfect height for a clean, professional finish.

2. Aggressive Weep Channels

Take a look at 00:02:08. FloFX designed wide, aggressive weep grooves that help water evaporate efficiently from under the tile into the drain body. Way better than those tiny holes on the Schluter.

3. Recessed Screw Holes

This one’s huge. The FloFX flange has recessed screw holes, so when you fasten it down, the screw heads sit flush — no bumps under the membrane, no tears. The Kerdi flange can’t do that. At 00:05:17, you’ll see how big a difference this makes.

4. Mechanical Mortar Lock Channels

Check out 00:06:34. The FloFX flange has channels molded into the underside. These let your thinset mechanically bond to the flange, locking it into place. Once it’s set, it’s rock-solid and won’t pop up like smooth ABS plastic can.

5. Sturdier Build Quality

When you hold them side-by-side, you can feel it — the FloFX is heavier and stiffer. It flexes less, which gives you a more solid installation overall.

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Step-by-Step Installation Guide

Step 1: Prep the Kerdi Foam Tray

(See 00:07:46) Start by dry-fitting your Kerdi foam tray to make sure it fits your shower footprint. Use a utility knife or rock knife to trim it to size. The Kerdi low-profile tray is only about an inch thick at the edges, so it cuts easily.

Once it’s trimmed, mix up modified lightweight thinset. Use a ½" x ½" notch trowel and comb all ridges in one direction. Press the tray firmly into the mortar, even stand on it a bit to collapse the ridges and get full contact. You want minimal air pockets underneath.

Step 2: Install the FloFX Drain

At 00:09:01, I start embedding the new FloFX flange. Here’s what to do:

• Use a ¼" x 3/16" V-notch trowel to spread thinset under the flange area and fill all those mortar lock cavities on the bottom.

• Apply ABS cement to both the drain pipe stub-out and the inside of the drain flange.

• Press the drain down while twisting it slightly to get a full bond and ensure coverage.

• Secure the flange using the recessed screw holes if possible (if you’re over wood subfloor). On concrete, the mortar lock alone does the job.

That’s it. Your FloFX flange is now fully seated, level, and mechanically locked into the Kerdi tray.

Why This Drain Is a Big Deal

Let’s be honest — this fix was long overdue. The FloFX bonding flange for Kerdi trays solves a compatibility issue that’s been bugging installers for years.

Now, you can have:

• The superior look and performance of FloFX grates

• The convenience of Kerdi’s pre-sloped foam pans

• And a rock-solid installation that’s fast, durable, and waterproof

No more trimming, hacking, or forcing parts that don’t fit. Just set it, bond it, and move on.

Side-by-Side Comparison

Feature	FloFX Bonding Flange	Schluter Kerdi Bonding Flange
Adjustment Ring	Thicker; flush with tile	Thinner; dips below tile
Weep Channels	Wide and aggressive	Small holes
Screw Holes	Recessed; sits flush	Small; screw heads protrude
Mortar Lock	Mechanical channels	Smooth ABS surface
Flexibility	Rigid and heavy-duty	Light; more flexible
Kit Contents	Flange + ring + grate carrier	Flange only (other parts sold separately)

The FloFX kit gives you everything you need in one box — no need to buy adjustment rings, grates, or extra accessories.

Why Choose FloFX?

1. Simplified Installation

With all parts included and a design built for Kerdi foam trays, this system saves time and frustration on-site.

2. Enhanced Drainage

The aggressive weep channels prevent moisture buildup, helping your tile surface dry out faster and reducing the risk of mold or efflorescence.

3. Professional-Grade Durability

The thicker ABS material resists flexing and cracking. You can feel the difference when handling it — it’s solid.

4. Made in the USA

FloFX is a small American company that actually listens to installers. Supporting them means supporting small business and keeping quality high.

FAQ — Frequently Asked Tile Coach Questions

Q. Can I use the old square FloFX flange with a Kerdi tray? 

No. The original FloFX flange was square and doesn’t fit the round Kerdi tray hole. This new version is designed specifically for Kerdi foam pans.

Q. Do I need any extra parts or adapters? 

Nope! The kit includes the bonding flange, adjustment ring, and grate carrier — ready to tile.

Q. Can I screw the flange down? 

Yes. FloFX designed recessed screw holes for flush fastening. This keeps the membrane smooth and secure.

Q. What thinset should I use? 

Use a highly modified, lightweight mortar  — it bonds great to foam.

Q. Will this work with all Kerdi trays? 

Yes. It fits the standard round drain openings used in Kerdi pre-sloped foam pans.

Final Thoughts

Honestly, I’m pumped about this one. It’s one of those small innovations that just makes life easier for installers and DIYers alike.

FloFX nailed it with this flange — it fits the Kerdi tray perfectly, and it actually comes with everything you need. You don’t have to chase down extra parts or fight with fitment issues.

If you want to pick one up, grab it from TileCoach FloFX Product page. You’ll be supporting a small, USA-based business that makes legit, pro-grade products.

Keep a couple of these on hand — once you use one, you won’t go back.

Thanks so much for reading and watching. I know there’s a lot of content out there, and I’m truly humbled you spent your time here with me. I love being your Tile Coach, and I’m here to make your tile projects easier, cleaner, and more professional.

Until next time — happy tiling, and take care!