I've been specifying and fitting Karndean for about ten years. In that time, I've made enough mistakes to fill a skip—roughly $6,200 worth by my count. Maybe $6,800; I'd have to check the spreadsheet. The lesson I keep coming back to is simple: the flooring itself is rarely the problem. It's what happens underneath it, and what nobody planned for.
Today I'm comparing the two systems I install most often: Karndean Looselay wood-effect planks and Karndean rigid core (the click-lock Korlok range). Both can look identical in a brochure. Both can look beautiful on your floor. But the preparation for one is not the same as the preparation for the other. That's where I've burned budget, time, and goodwill.
What this comparison is based on
I'm not going to tell you one of these is "the best." That's not how site work happens. What I can do is compare them on the things that actually cause callbacks: subfloor flatness, underlayment and movement, wet areas, cleaning, and repairs. If you're debating Karndean Looselay wood vs rigid core, those are the decisions that will decide whether the floor is still there in five years.
Looselay means exactly what it sounds like: the planks are laid without adhesive, relying on a grip backing and the weight of the floor to stay put. Rigid core planks click together and float, usually with an attached underlayment. That difference in construction changes everything downstream.
Dimension 1: Subfloor flatness
Loose lay depends on friction. The backing grabs the subfloor, but it cannot disguise a hollow or a hump. If the subfloor has an old trowel ridge, a low spot, or a bump from adhesive, the plank will sit on it like a bridge and rock when someone walks past. I check every floor with a 2m straightedge before I open a box.
Rigid core is more forgiving. Because the planks are thicker and stiffer, they hide small undulations that would make loose lay rock. That doesn't mean rigid core likes a bad floor. It just complains later, usually at the joints.
In September 2022, I approved a concrete subfloor that my boot told me was flat. I didn't put a straightedge on it. The loose lay planks looked fine for two weeks; then the joints started rocking underfoot. The section had to come up and the floor was levelled again. It cost about $1,300—no, $1,150; I'm mixing it up with a different job. It was enough to hurt.
That failure changed how I think about "flat enough." When I compared the two systems side by side, I understood something: rigid core was hiding the subfloor's sins, not fixing them. Looselay was just being honest about them.
Dimension 2: Underlayment, foil board and movement
This is where good intentions go to die. Somebody watches a late-night video about underfloor heating, or a neighbour mentions drafty floors, and all of a sudden there is a roll of foil board sitting in the room.
Foil board can work under some floating floors. It does not automatically work under Karndean Looselay. Because loose lay holds by grip, a slick foil surface turns it into a skating rink. There was a job in March 2023 where the owner was very proud of the foil board he'd laid "to keep the floor warm." The Karndean guide was on the passenger seat. The foil board went back to the garage.
If you're using rigid core with a click-lock system, a compliant underlayment is often built in or specified. But for Looselay, read the fitter guide first. All vinyl moves with temperature changes. Rigid core can buckle if you lock it tight against the skirting or cabinets. Loose lay can creep if there's nothing for the grip to hold onto. Expansion is not an optional thought with either system.
Dimension 3: Bathrooms, water and the shower valve
Karndean is water-resistant, not waterproof. Neither loose lay nor rigid core will hold back water forever. If water gets under a loose-lay plank, it can move quietly across the room. If it gets into a click joint, it sits there and causes its own drama. I don't want to oversell either system in a bathroom.
If you're putting new flooring in a bathroom, this is also the moment to think about the shower valve. It feels unrelated, but it isn't. An old valve can start dripping after the floor is finished, and then the repair work happens above a brand-new floor. In 2020, I finished a bathroom floor on a Tuesday. Six months later the shower valve started dripping. The plumber had to stand on a step ladder over that floor with a wrench and a soldering torch. I did not relax until he was out of the room.
Oh, and if you do use Looselay in a bathroom, seal around the perimeter with a flexible silicone. It won't make the floor invincible, but it stops water finding the edge.
Dimension 4: Cleaning and the Screwfix question
This sounds ridiculous, but I get asked about "karndean floor cleaner screwfix" more often than I get asked about underlayment. Search for it and you'll get a list of products. Some are fine. Some will leave a haze that makes the wood effect look cloudy—which, honestly, is worse than the dirt.
I used to think any floor cleaner was acceptable. In 2018, I used a "shine restorer" from a builders' merchant on a Karndean floor and spent two weekends cleaning off the streaks. The product wasn't cheap, and it wasn't dirtying the floor. It was leaving an acrylic film. Karndean's maintenance guide asks for a neutral pH cleaner, not a polish. If the label says "wet look" or "acrylic finish," put it back. That applies whether you buy from Screwfix or direct from Karndean.
For normal use, dry mop first, then a lightly damp mop with the right cleaner. Don't use a steam mop. Steam can push water into the joints and the backing, and that's how edge swelling starts.
How to clean baseboard heaters without making the floor worse
I know this heading looks odd in a floor-covering article, but after a floor is installed, the phrase "how to clean baseboard heaters" suddenly matters. Sanding and cutting vinyl leaves fine dust, and that dust settles into the heater fins. When the heating turns on, it smells like a sawdust barbecue.
Turn the heater off and let it cool. Vacuum the fins with a brush attachment, then run a microfiber cloth wrapped around a ruler between the fins. Don't use water sprays or surface cleaner. Wet dust sticks to the metal and collects more dust. This is not a Karndean task, but it's the kind of final detail that separates a nice install from a great one.
Dimension 5: Repairs and long-term maintenance
If a plank gets scratched or damaged, the best repair is invisible. But the two systems make that very different.
- Loose lay: a single plank can usually be lifted and swapped, provided you kept a spare from the original batch. I've done this in 30 minutes in a living room.
- Rigid core: a damaged plank in the middle of a room means working back from the edge to release the click locks, or cutting out the plank and gluing in a replacement. It's slower. On the other hand, rigid core is less likely to show dents from point loads.
Never expected the maintenance difference to matter so much. But over a 10-year life, a floor that can be repaired without dismantling half the room is worth real money.
Verdict: what I'd choose and why
If the subfloor is flat, the room has normal foot traffic, and I want a true wood effect with no glue smell, I'd choose Karndean Looselay wood. It's fast, beautiful, and forgiving to change. It has also become a favourite for staged homes, because a room can be lifted and changed when the furniture leaves.
If the room has rolling chairs, an uneven subfloor, or a slab that moves with the weather, I'd choose rigid core. It's less nervous about heavy point loads and keeps its joints true when temperatures change. For a kitchen, utility room, or bathroom, I'd go with Karndean glue down and welded seams before I let water near either system.
Even after choosing rigid core for my own office, I kept second-guessing. Maybe the loose lay would look better? But my chair has castors, and the heating runs overnight. The rigid core hasn't moved in a year. That's the kind of boring success I now want.
The product category has changed. Five years ago, vinyl was the cheap option; now, a Karndean herringbone in a natural wood finish belongs in the same sentence as hardwood. What hasn't changed: the floor is only as good as the subfloor under it and the installer who reads the spec. If something sounds easy, ask easy for what. Then get the straightedge out.
