Do You Need Underlayment Under LVP?

Usually, no. Most luxury vinyl plank sold today already has a pad bonded to the bottom of the plank at the factory, and over a sound wood subfloor that pad is doing the job on its own. Buying a second layer there is nice, not necessary.

Over a concrete slab, our answer changes. There we recommend adding underlayment underneath the plank anyway, and we'll explain exactly why below.

That's the short version. Here's the longer one, subfloor by subfloor, because this is the question we get asked at the counter in Madisonville more than almost any other question about vinyl plank.

What does underlayment actually do?

Underlayment is a thin roll of foam, felt, or cork that goes down between your subfloor (the structural deck under your finished floor) and the flooring itself. It does four things, and it's worth separating them, because most of the confusion around this question comes from treating them as one:

• Cushion. It takes the hardness out of a floor you stand on.
• Sound. It absorbs the hollow click a floating floor can make and keeps footsteps from carrying into the room below.
• Moisture. A proper underlayment over concrete acts as a barrier between the slab and your floor.
• Minor smoothing. It hides very small imperfections in the surface underneath.

Nobody notices a quiet floor. That's the point.

Does LVP come with underlayment already attached?

Most of it does. On the vast majority of planks we sell, there's a thin pad, usually cork or foam, glued to the bottom of the plank before it ever reaches us. It's part of the plank, not something you install separately.

That attached pad is why the honest answer to "do I need underlayment" is usually no. It already cushions, quiets, and smooths over the small stuff. If you want the whole cross-section of a plank explained layer by layer, including the three pad types we've seen hold up best, we took one apart in What Is LVP Made Of?

Do you need underlayment for LVP over a wood subfloor?

Nice, but not necessary.

Over a sound wood subfloor, a plank with an attached pad has what it needs. Adding a layer underneath will make the floor a little softer and a little quieter, and if those things matter to you in a bedroom or an upstairs room, it's a reasonable thing to buy. It is not something we'll tell you that you have to have, and we're not going to add it to your material list and hope you don't ask.

Do you need underlayment for LVP on a concrete slab?

Here, yes. This is the one install where we actively recommend it.

Concrete gives off moisture. A slab that looks bone dry can still pass water vapor up through itself for years, and that vapor has to go somewhere once there's a floor sitting on it. An underlayment made for concrete adds a real moisture barrier between the slab and your plank, on top of whatever the plank's attached pad already provides.

The other two reasons are comfort ones, and on a slab they matter more than people expect. Concrete is hard and concrete is cold. A floor laid straight onto it feels like what it's laid on. The extra layer adds softness underfoot and takes the echo out of the room, and in a basement or a slab-on-grade house that difference is the difference between a room you use and a room you walk through.

Over concrete, we treat underlayment as part of the floor, not an upgrade to it.

There is a specific underlayment we use over concrete on our own installs. Ask us about it when you're pricing a slab project and we'll show you the one we mean.

Does glue-down LVP need underlayment?

No, and this one is not a judgment call. Glue-down never gets an underlayment.

A glue-down floor is bonded directly to the substrate with adhesive, so by design there is nothing in between. Putting a soft, compressible layer under a floor that is meant to be stuck down works against the whole point of the install.

It's worth saying plainly, because underlayment is one of the easier things to buy for the wrong kind of job. Everything else on this page is about floating floors, the click-together kind that rest on the subfloor rather than bond to it. If your floor is going down in adhesive, skip the underlayment line entirely and put the attention into the substrate underneath it.

Can you put underlayment under LVP that already has a pad?

It depends on the plank, and we mean that as a real answer rather than a dodge.

Some floors take a thin underlayment underneath without any trouble. On others it's the wrong move, and the reasons come down to the specific product rather than to any rule that covers all vinyl plank. This is one of the places where the advice you find online is confidently wrong in both directions, because whoever wrote it was thinking about one floor and you're buying a different one.

Check the spec sheet that comes with your plank. Manufacturers spell out what is allowed underneath their product, and installing against it can affect your warranty. That is not a thing you want to learn the boundaries of after the floor is down.

If you bought your plank from us, you don't have to go hunting for the answer. Tell us which floor you're looking at and we'll tell you what belongs under it.

What underlayment will not fix

This is the part worth reading twice, because it's where we see floors fail.

Underlayment can quiet a floor and warm it. It cannot flatten it.

A click-together plank floor needs a flat surface underneath, and flat is not the same as level. Level is about slope. Flat is about humps and dips. A floating floor bridges a dip instead of filling it, and every step across that bridge works the click joints against each other until they separate, peak, or start making noise. That is the single most common way we see a vinyl plank floor come apart, and it happens with WPC and SPC alike.

A quarter inch of foam does not solve a subfloor problem. It hides it for a season. If the slab or the deck under your floor has humps or dips, they get ground down or filled before anything goes on top, and that's true whether you're buying underlayment or not. We wrote up what that prep actually involves in Floor Preparation and Installation.

What does underlayment cost?

Relative to the floor itself, not much. Underlayment is one of the smaller numbers on a flooring quote, and on a concrete slab it's the one we'd argue hardest to keep on the list, because it's buying you a moisture barrier and daily comfort for a fraction of what the plank costs.

Over a wood subfloor, it's the opposite conversation. If the budget is tight and the subfloor is sound, this is a line you can cut without hurting the floor. We'd rather you put that money toward a 20 mil wear layer, which is the number that decides how your floor looks in five years, than toward padding a floor that's already padded. If you're still deciding between plank types, WPC vs SPC: Which One Should You Buy? covers that call.

The short answers

• Plank with an attached pad, over a sound wood subfloor? You don't need extra underlayment. Buy it if you want a softer, quieter room.
• Any plank, over a concrete slab? Add it. Moisture barrier, warmth, and quiet, and we'll point you at the one we use.
• Glue-down install? No underlayment, ever. It bonds straight to the substrate.
• Adding one under a plank that already has a pad? Depends on the plank. Check its spec sheet, or tell us which floor it is and we'll tell you.
• Uneven subfloor? Underlayment is not the answer. Flatten it first.

Bring us the room and the subfloor and we'll tell you which of those you're in, including the times the answer saves you money. Come see the LVP lines we carry and install in the Madisonville showroom, or request a free estimate and we'll come measure and bring samples with us.