Karndean Flooring for Bathrooms: A Realistic Look at LVT in Wet Areas (and When It Might Not Be Right)

Let's be direct: if you're searching for 'Karndean vinyl bathroom flooring,' you've probably heard a few conflicting things. Some installers say it's a no-brainer. Others say you're asking for trouble. The truth, as with most things in construction, is that it depends entirely on your specific situation.

I manage facility improvements for a mid-size property management company—roughly 60-80 projects a year across 3 locations. We've specified Karndean in about a dozen bathroom renos over the last 4 years, and we've learned some lessons the hard way. Here's what I can tell you based on that experience.

The Big Question: Is Karndean "Waterproof"?

Technically, no. And anyone telling you otherwise is oversimplifying. Luxury Vinyl Tile (LVT) like Karndean is incredibly water-resistant, but it's not a submarine.

Here's the thing: the vinyl itself is 100% waterproof. It won't absorb moisture, swell, or rot. The problem is the installation system—the subfloor, the adhesive (if you're using glue-down), and the seams where planks meet. Water can find its way through or under the floor if these aren't handled perfectly.

So the question isn't 'is it waterproof?' It's 'can my bathroom be made suitable for it?' Let's break that into three common scenarios.

Scenario A: The Full-Family Bathroom (High Moisture, High Traffic)

The Challenge

This is the bathroom that gets used by kids for daily showers, has a tub that sees splash battles, and maybe has a slightly leaky toilet seal that you haven't gotten around to fixing. Moisture isn't occasional—it's a constant presence.

What We Do

For this scenario, we almost always recommend Karndean's Korlok click-lock system. Here's why: it's designed with a rigid core and a tight locking mechanism that creates a more robust barrier against moisture seeping between planks.

But—and this is a critical 'but'—you cannot just lay it over an imperfect subfloor. The manufacturer's specifications require a very flat, clean surface (< 3/16" variation over 10 feet). For a bathroom that's already had water damage, that often means a self-leveling compound is non-negotiable.

More importantly, we always test for moisture in the concrete slab before installation. We use a calcium chloride test. If the MVER (moisture vapor emission rate) is above 5 lbs per 1,000 sq ft per 24 hours, Korlok is a risky choice. You'd need an epoxy moisture barrier first.

What I'd do differently on my last one: We skipped the perimeter expansion gap in a small 5x7 bathroom. Thought it was small enough to not matter. The floor buckled at the seam near the shower threshold within 6 months. We had to pull it up and reinstall with a proper 1/4" gap. Learn from my mistake.

Scenario B: The Guest or Powder Room (Low Moisture, Occasional Use)

The Challenge

This is the half-bath downstairs that gets used by guests. Maybe there's no shower, just a toilet and a sink. The floor sees some splashes, but nothing prolonged.

What We Do

This is where Karndean shines. We typically specify a glue-down product like their Art Select collection for these spaces.

Why glue-down? It's cheaper, has a thinner profile (easier to transition to adjacent hardwood), and when installed properly with a full-spread adhesive, it's very water-resistant. The biggest risk here isn't moisture from above—it's moisture from below. A damp basement slab can cause the adhesive to fail, leading to loose tiles.

In this scenario, we ask a different question: 'What's the subfloor?' If it's a concrete slab on grade, we always install a vapor barrier underneath (6-mil poly sheeting, overlapped 6 inches). If it's a wood subfloor over a crawl space? We check the humidity levels in the crawl space first.

Most people miss: The grout lines. In a powder room with a glue-down tile look, the grout lines (the spaces between the planks) are purely decorative. They're not a waterproof joint. Water can still wick under the tile. For this room, it's rarely an issue, but it's something to be aware of.

Scenario C: The Wet Room or Large Shower Enclosure

The Challenge

This is the most demanding application. We're not talking bathroom flooring near the shower. We're talking the floor inside the shower, or a full, open wet room where water covers the entire floor during use.

The Verdict

We've stopped using Karndean in these areas. Period. For a 60" x 36" shower floor, we use a proper tiled pan with a waterproof membrane (like Schluter-KERDI or a liquid-applied membrane).

The problem isn't the vinyl. The problem is the sheer volume of standing water and the inability to ensure a 100% watertight seal at the drain and wall junctions. A single, tiny gap in the caulking at the corner can funnel water under the floor, destroying the subfloor over time. The risk-to-reward ratio just isn't there for us.

"What most people don't realize is that the floor is only as waterproof as the weakest seam. And in a wet room, there's a seam every 6 inches."

How to Decide Which Scenario You're In

The Rule: If water sits on the floor for more than a few minutes at a time (shower), don't use it. If it's a standard bathroom with a shower, proceed with caution and a perfect install. If it's a powder room, it's a slam dunk.

Here's a quick checklist to run through before you buy:

• What's the room size? (Small rooms need expansion gaps, counter-intuitively.)
• What's the subfloor material and condition? (Concrete? Wood? Cracked? Flat?)
• Is there a shower or tub in the same room? (If yes, scenario A.)
• Can you guarantee the toilet and sink supply lines won't leak? (No. So plan for it.)
• How will you transition to the adjacent flooring? (A proper T-molding or reducer is critical to prevent moisture wicking.)

We use a simple decision matrix for our projects. If two or more of the above are a concern, we specify a different product or budget for significantly more prep work.

Did I justify this decision perfectly every time? No. I approved a glue-down install in a kid's bathroom last year despite a sketchy subfloor. I got lucky—it's holding up fine. But that feeling of 'did I make the right call?' hung over me until the first inspection. It's a gamble I don't recommend taking with your own home.

The Bottom Line on Bathroom Flooring

Karndean is a premium product. The designs are better than many mid-range tile, and it's warmer and quieter underfoot. For the right application—a well-prepared bathroom with controlled moisture—it's a fantastic choice that will last 15-20 years.

For a high-moisture family bathroom or a full wet room? Spend the money on a proper tiled floor with a membrane. You'll sleep better at night, and so will your subfloor.

Pricing note: Based on our Q3 2024 projects, a standard glue-down Karndean bathroom install (materials and labor) runs $8-$12/sq ft. A Korlok install is $10-$15/sq ft. Always verify current pricing with your local distributor, as rates can vary.