Yes, Karndean flooring is waterproof—mostly. That’s the conclusion I reached after three months of research, three installer quotes, and one expensive mistake with a different brand. The real issue isn’t whether the planks themselves resist water. It’s whether the installation handles seams, edges, and transitions correctly. We ended up installing Karndean herringbone vinyl flooring in our office lobby and breakroom, and I’d make the same call again—but not for the reason most people expect.
I’m an office administrator for a 90-person architecture firm. I manage facility purchasing—about $400,000 a year across 15 vendors. When we decided to renovate the first floor, I got pulled into flooring selection. I don’t have a construction background, but I’ve learned that the cheapest price is rarely the cheapest floor. That’s worth explaining here, because the waterproof question is connected to that.
What “Waterproof” Actually Means
From the outside, all waterproof vinyl looks similar. The reality is different product lines have different cores and installation methods. Karndean’s rigid core and loose lay collections are the ones the company lists as waterproof. The core is engineered to be dimensionally stable and won’t swell like older wood- or MDF-based products. But that doesn’t mean water can’t get through the joints or under the floor if the edges aren’t sealed.
What most people don’t realize is that “waterproof plank” is not the same as “waterproof installation.” Water works its way through the smallest gaps. I saw this with our café floor back in 2021. That one was a different LVT brand, but the principle applies everywhere. We assumed the waterproof rating covered every inch of the surface. Six months later, the edge near the serving counter curled because the transition strip wasn’t sealed. The distributor said it wasn’t a product failure—it was a seam issue. Took a $2,300 repair to teach me that.
Because I’m the person signing the purchase order, I also checked what the FTC says about advertising claims. Per FTC guidelines, claims like “waterproof” need to be substantiated. So I asked Karndean for test data, not just a brochure. They provided results for the specific series we were considering, and I forwarded those to the installers.
The Price Trap
Karndean was not the lowest quote we got. Two other LVT brands came in 15–20% lower per square foot. But I’ve been doing purchasing long enough to know that comparing square foot prices alone is how you end up spending more. The cheaper planks had a 12 mil wear layer; the Karndean product we specified had a 20 mil wear layer (that’s the transparent coating on top of the design). In a corridor with carts and heels, a 12 mil wear layer will show wear in maybe four or five years. A 20 mil layer is built for a longer commercial life.
Let me put it in numbers. The cheap quote would have saved about $1,800 upfront. If that floor wears out in five years, we’d pay at least $6,000 to replace it—plus the disruption of moving furniture and closing two rooms. Over ten years, the cheap floor costs more even though it starts out cheaper. That’s the calculation I use for every significant purchase now. Real talk: I’d rather explain why we spent a bit more upfront than explain why we need another renovation in five years.
Oh, and the cheaper quote didn’t include removing the old carpet—that added another $0.75 per square foot when we asked. It was one more hidden cost that a lower unit price conveniently ignored.
Why Herringbone Changes the Equation
Once we chose the herringbone pattern, the installer became more important than the product. Herringbone has more cuts and more seams than a straight-lay floor. Those seams are where water creeps in. One installer bid 18% less because he planned to skip the moisture test and install directly over the old slab. I turned him down. Another bid 20% more but included moisture testing, a moisture barrier, seam sealing, and a written installation warranty. That’s the bid I accepted.
I have mixed feelings about spending 20% more on installation. On one hand, it feels like a markup. On the other hand, I’ve already paid the price once for ignoring seam sealing. The extra money buys a written guarantee that if water gets in through a seam, the installer comes back and fixes it. In an office, that kind of assurance is worth more than the discount.
Where the Waterproof Claim Ends
I’d be lying if I said Karndean is indestructible. It isn’t. The waterproof claim assumes normal conditions—spills get wiped up reasonably soon, no standing water for days, no steam mops on high heat, indoors only. The warranty also depends on following Karndean’s installation guide. If the subfloor is damp, if expansion gaps are too tight, or if the wrong adhesive (when adhesive is required) is used, the floor may fail and the warranty won’t cover it.
Also, not every Karndean product is equally waterproof. The rigid core and loose lay ranges have the strongest waterproof claims. Some glue-down products are water-resistant rather than fully waterproof. When in doubt, ask your supplier for the technical data sheet for the exact series you’re considering, and ask specifically whether it covers seamed joints. If they can’t answer, that’s a red flag.
One last thing I’ve learned the hard way: order a few extra planks and store them somewhere dry. If a single plank gets damaged in a year, you’ll thank yourself for having spares from the same batch. Matching a herringbone pattern from a different production run is not fun. I once spent a full afternoon calling distributors to find a discontinued color—worst Tuesday of my life.
