Do You Need Underlayment for Vinyl Plank Flooring?
Short answer: It depends on the plank. If your vinyl plank has a pre-attached pad, do not add underlayment — it can void the warranty and cause the locking joints to flex and fail. If it has no attached pad, underlayment is recommended for comfort and sound. Over concrete, a moisture barrier is required either way.
David Shaoulpour
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Start by checking the plank
Turn a plank over. Many rigid-core and luxury vinyl products ship with a pre-attached pad — usually IXPE or EVA foam bonded to the underside.
If yours has one, do not add more underlayment. This is the most common and most expensive install mistake with modern LVP. Too much cushion lets the floor flex under foot, and repeated flexing works the locking joints loose. The result is gapping and separated seams, and almost every manufacturer excludes it from warranty coverage.
If there is no attached pad, underlayment is worth adding.
What underlayment actually does
Sound. The biggest practical benefit. It reduces both the hollow tapping you hear when walking and the noise transmitted to rooms below. In apartments and upper floors this is often a building requirement.
Comfort. A modest softening underfoot and slightly better thermal insulation.
Minor subfloor smoothing. It hides very small imperfections — but it is not a levelling product. Anything more than about 3 mm over 2 m needs proper levelling compound first.
Moisture protection. Only if it includes a vapour barrier.
The concrete rule
Over any concrete slab — including above-grade slabs, and especially basements — you need a moisture barrier, typically 6-mil polyethylene, or an underlayment with a barrier built in.
Concrete releases water vapour continuously, even when it looks and feels bone dry. Without a barrier, that vapour becomes trapped under the floor, and you get mould and adhesive failure. This applies even to fully waterproof planks: the plank is not the thing at risk, the space beneath it is.
If your plank already has an attached pad and you are over concrete, use a thin standalone vapour barrier only — not a cushioned underlayment.
Choosing a thickness
For vinyl plank, 1–1.5 mm is the correct range. Thicker is not better here. Underlayment made for laminate is often 2–3 mm, which is too soft for LVP's thinner profile and will cause exactly the joint flexing described above.
Quick reference
Your situation | What you need |
|---|---|
Plank with attached pad, wood subfloor | Nothing |
Plank with attached pad, concrete | Thin vapour barrier only |
No attached pad, wood subfloor | 1–1.5 mm LVP underlayment |
No attached pad, concrete | 1–1.5 mm underlayment with vapour barrier |
Upstairs or apartment | Acoustic underlayment — check building rules |
Glue-down installation | None — planks bond directly to the subfloor |
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Frequently asked questions
Can you install vinyl plank flooring without underlayment?
Yes, if the plank has an attached pad or you are installing glue-down. Over concrete you still need a vapour barrier.
What happens if you use underlayment with an attached-pad plank?
The floor becomes too soft underfoot, planks flex at the seams, and the locking joints gradually work loose and gap. It typically voids the warranty.
Does underlayment make vinyl plank flooring quieter?
Yes — that is its main benefit. Acoustic underlayment noticeably reduces both hollow footfall sound and noise transmitted to the room below.
Is thicker underlayment better?
No. For vinyl plank, 1–1.5 mm is correct. Thicker products designed for laminate cause joint flex and premature failure.
