If you're installing Karndean in a bathroom, your prep work matters more than the product itself—and I learned that the expensive way.
In December 2022, I installed a Van Gogh collection plank (the herringbone pattern, which I was really proud of) in a master bathroom. Six weeks later, I was pulling it up. The edges were lifting, the adhesive was failing in two corners, and the homeowner had a $3,200 repair bill—plus a 1-week delay. I'd followed the manufacturer's instructions to the letter. Or so I thought.
That job cost me $890 in materials and redo labor, plus a chunk of credibility with a client who'd been a referral source. The mistake? I'd prepped the subfloor like I always did for dry areas. The bathroom needed different prep. And nobody had told me—not the distributor, not the training video, not the spec sheet. (I've since made it my mission to document every failure so my team doesn't repeat it.)
Karndean Is Water-Resistant, Not Waterproof—and That Distinction Matters
The marketing materials will say "luxury vinyl is perfect for bathrooms." And it is—if you treat it like a premium product that needs proper installation, not a magic shield. Karndean's LVT (including the Korlok click-lock and loose-lay options) is highly water-resistant. But here's the catch: water can seep through seams, especially in planks that aren't glued down properly, and it can get trapped under the flooring if the subfloor isn't perfectly flat and sealed.
On that bathroom job, I'd used a glue-down LVT from the Knight Tile collection. I checked the adhesive coverage—looked fine on a sample. But in practice, the subfloor had a slight dip (maybe 1/8 inch over 4 feet) that I hadn't noticed. The adhesive didn't bond fully in that low spot. Water from a splashing shower found its way in, and within weeks, I had a failure.
The lesson: Subfloor prep for bathrooms is non-negotiable. You need a perfectly flat, fully sealed substrate. If you're using glue-down, check adhesive coverage with a trowel notch that's appropriate for the specific plank (not just the general recommendation). And for click-lock (Korlok), make sure the expansion gap is sufficient—humidity changes in bathrooms are more dramatic than in living rooms.
The "Bald Cap" Mistake (Yes, That's Real)
I once had a job—a small bathroom, maybe 50 square feet—where the homeowner asked if they could just put the planks down without adhesive, like a floating floor. I said no, but they found a neighbor who'd done it. That neighbor had what I now call "bald cap syndrome": he'd installed the LVT without proper edge sealing, and within three months, the corners were curling up like a bad toupee. (I have a photo of it I show trainees. It's both hilarious and tragic.)
Karndean's loose-lay (Looselay) is designed to be installed without adhesive in some cases, but only with a specific underlayment and edge sealing. The Korlok click system is designed for floating installation, but you still need to seal the perimeter. If you skip sealing, moisture wicks up from the concrete or plywood subfloor, and you get that bald-cap effect.
I have mixed feelings about DIY installation in bathrooms. On one hand, it's doable if you're meticulous. On the other, I've seen too many $800 mistakes that could have been avoided with a $30 moisture meter and 30 minutes of prep.
How Much Does Karndean Flooring Cost for a Bathroom?
Let's talk numbers, because this is where surprises hide. Based on pricing I've tracked from multiple distributors (as of January 2025), here's a realistic range for a typical bathroom (40-60 sq ft):
- Materials only: $300–$600 for Karndean LVT (Van Gogh or Knight Tile collections; Art Select is pricier)
- Adhesive and underlayment: $80–$150
- Professional installation (labor): $400–$800 (varies by region and complexity)
- Subfloor prep (if needed): $100–$300 for leveling compound and sealant
Total for a professional install: $880–$1,850 (based on average quotes from certified installers in the Midwest, January 2025; verify current pricing with local distributors).
If you go the DIY route with click-lock (Korlok), you can save on labor but might spend $100–$200 on tools you don't have (moisture meter, trowel, cutting tools). And if you make the subfloor mistake I made, the redo cost will exceed any savings.
Check Valve vs. Expansion Gap: A Plumbing Analogy That Helps
I've been installing flooring for 4 years, and I've made (and documented) 9 significant mistakes, totaling roughly $4,700 in wasted budget. But one of the weirdest lessons came from a plumbing job, not a flooring one.
When a plumber installs a check valve, they make sure water can only flow one way. Flooring works the same: moisture can only come from one direction (up through the subfloor or down from spills), and your installation needs to create a one-way barrier. If you don't seal the subfloor properly, moisture acts like a failed check valve—it flows backward into your flooring. (This analogy came from watching a plumber fix my own bathroom. I stood there thinking, "That's exactly what I'm doing wrong with LVT.")
The fix: Use a vapor barrier or sealant on concrete subfloors. For wood subfloors, make sure there's adequate ventilation underneath. And always—always—check the moisture content of the subfloor before installation. The USPS standard letter costs $0.73 as of January 2025. A $15 moisture meter can save you $3,000. That's a good investment.
Two Exceptions: When Karndean Bathroom Installations Go Wrong (and One When They Don't)
Exception 1: Steam showers and wet rooms. If the bathroom has a steam shower, you need a completely different approach—I'd recommend a tileable shower pan or a fully waterproof membrane, not LVT. Karndean is great for bathrooms that get splashes, but not continuous steam. I've seen the adhesive fail in steam rooms within 6 months.
Exception 2: Below-grade bathrooms. Basement bathrooms with inadequate drainage or high groundwater create a moisture sandwich. The LVT might be fine, but the subfloor might not be. In these cases, I always recommend a professional moisture test before installation. (Per FTC guidelines on product claims, manufacturers can't guarantee performance in conditions they haven't tested. Karndean's warranty documentation is clear about this.)
The one case where it's foolproof: A powder room (no shower or bathtub) with a well-sealed subfloor. In that setup, Karndean LVT is nearly perfect. I've installed it in three powder rooms with zero issues over 2+ years. No special tricks beyond good prep.
I get why people go with the cheapest option—budgets are real. But the hidden costs add up. The way I see it, the extra $100–$200 you spend on proper subfloor prep and moisture management is the cheapest insurance you'll ever buy.
Pricing is for general reference only. Actual prices vary by region, distributor, and specific product choices. Verify current rates with local Karndean distributors. Subfloor and installation advice is based on my personal experience; always consult a professional installer for your specific conditions.
