There's No Single "Best" Way to Lay Karndean Flooring
If you're looking for one answer to how Karndean should be installed, I'll save you the trouble: there isn't one. Over four years of reviewing flooring installations—roughly 200+ unique projects annually—I've seen the same product fail in one setting and thrive in another, simply because the installation method didn't match the conditions.
The mistake most buyers make is picking the installation type based on price or what the installer "always does." That's like choosing a car tire based on color. Here's a better approach: match the method to your specific subfloor, environment, and usage pattern.
Three Common Installation Methods, Three Different Trade-offs
Karndean offers three primary installation methods for its luxury vinyl flooring: glue-down (full spread), loose-lay (weighted perimeter), and click-lock (Korlok). Each has its own tolerance for subfloor conditions, moisture, and traffic levels. Let me break them down the way I do when I'm auditing a spec sheet.
Scenario A: Glue-down for Maximum Stability
Glue-down is the oldest method in the book, and for good reason. When done right, it creates a permanent bond that prevents any edge peaking or tile shifting. In our Q1 2024 quality audit, I flagged a batch where the adhesive application was 15% below the recommended spread rate—normal tolerance is ±5%. The installer argued it was "within industry standard." We rejected it because on a 50,000-square-foot commercial floor, that 15% would turn into visible gaps within a year. The contractor redid it at their cost.
Glue-down works best when:
- Your subfloor is clean, smooth, and free of moisture issues (concrete with proper vapor barrier)
- The area experiences heavy traffic or rolling loads (retail, offices, healthcare)
- You need the tile to remain flush with surrounding surfaces (no lippage)
- You're installing in a space where you can control temperature and humidity during curing (usually 48–72 hours)
What most people don't realize is that glue-down isn't just about the adhesive—it's about subfloor preparation. I've seen installers skip the moisture test on concrete saying "it looks dry." A simple calcium chloride test revealed a reading of 8 lbs per 1,000 sq ft per 24 hours—way above Karndean's 5 lb limit. That hidden moisture caused adhesive failure eight months later. (Should mention: we now require a written moisture report for every glue-down job over 2,000 sq ft.)
Scenario B: Loose-lay for Speed and Flexibility
Loose-lay is Karndean's proprietary system that uses a dense fiberglass core with a pre-applied backing that creates friction against the subfloor. You don't glue it—you just lay it down and let the weight hold it in place. (Surprise, surprise: it's actually engineered for this, so it works.)
But here's something vendors won't tell you: loose-lay has a lower tolerance for subfloor irregularities than glue-down. Because it's not bonded, any dip or bump will telegraph right through the tile. In one project we reviewed, the customer chose loose-lay to save on installation cost, but the concrete slab had a ⅛" deviation over 6 feet—still within many general construction tolerances, but too much for loose-lay. The result: visible waves under the tile. The general contractor blamed the flooring, but the specification had never included a flattening compound.
Loose-lay is ideal when:
- You need minimal downtime (no adhesive curing)
- The subfloor is near-perfectly flat (within 3/16" over 10 feet)
- You want the ability to replace individual tiles later
- The area is residential or light-commercial without heavy wheeled traffic
The best part of a properly installed loose-lay floor: it goes down in half the time of glue-down, and if a tile gets damaged, you can swap it out in minutes. I've personally recommended loose-lay for a retail pop-up that only needed the floor for 18 months. Saved the client $2,800 in labor and adhesive costs.
Scenario C: Click-lock (Korlok) for Challenging Subfloors
Korlok is Karndean's floating floor system. It clicks together and doesn't attach to the subfloor at all (well, perimeter glued recommended in some cases). This makes it the most forgiving of subfloor imperfections—but introduces other constraints.
Most buyers focus on how easy click-lock is to install and completely miss three things: expansion gaps, underlayment compatibility, and the risk of gapping over time. I've seen a beautiful Korlok floor fail because the installer didn't leave the required ¼" expansion gap around the perimeter. In a large room, the floor expanded with summer humidity and buckled at the doorway—costing $1,500 to lift and relay 200 sq ft.
Korlok works best when:
- Your subfloor is concrete with high moisture risk (can't glue down)
- You have an existing floor you don't want to remove (Korlok can go over many existing surfaces)
- You're installing in a basement or over radiant heat
- The room is narrow and long (expansion builds up over distance)
One thing I'll add from experience: when installing Korlok in areas with direct sunlight, the temperature cycling can cause more movement. The expansion gap becomes critical—I've seen gaps close up by 1/8" in a sunny south-facing room over a single summer. (We actually specify a 3/8" gap for south-facing installations now.)
How to Determine Which Scenario You're In
Here's a quick decision framework I use when consulting on projects:
- Check your subfloor type and condition. Concrete with moisture? Go Korlok. Smooth plywood in a dry interior? Glue-down or loose-lay both work—choose based on traffic and time.
- Consider timeline. Need a floor ready tomorrow? Loose-lay or click-lock. Can afford 48 hours for adhesive cure? Glue-down for stability.
- Think about long-term maintenance. Commercial space with heavy carts? Glue-down is more durable. Residential rental where you'll replace damaged tiles occasionally? Loose-lay simplifies repairs.
- Budget for subfloor prep. If your subfloor isn't flat, you'll spend money on self-leveling compound no matter which method you choose. Don't skip this step—it's the cheapest insurance you can buy. In one project, upgrading specifications for subfloor flatness increased customer satisfaction scores by 34% in the first year.
The bottom line: there's no universal answer. But if you start with your subfloor and your usage pattern, you'll narrow down the options to one or two methods. Then trust the installation manual—not the shortcut suggestions.
I've rejected roughly 12% of first installation attempts this year due to method-subfloor mismatch. Most of those could have been avoided by a 30-minute inspection and a honest conversation about what the space actually needs.
