Underlay for Laminate Flooring: Why You Need It and How to Choose

Underlay is the layer most people forget when they budget for a laminate floor — and the one that quietly makes or breaks how it performs. Unlike some hybrid boards that come with underlay attached, laminate needs a separate underlay laid underneath it, and it's sold separately. Here's why it matters and how to choose.

What underlay actually does

A thin foam or rubber layer might not look like much, but it does several important jobs at once:

Moisture protection — a good underlay adds a barrier between your subfloor and the laminate, protecting the pressed-wood core from moisture rising up from below (especially important over concrete).
Acoustics — laminate is naturally a little firmer and noisier underfoot than hybrid. The right underlay absorbs sound, softening the hollow tap and reducing noise to the rooms below.
Comfort — it takes a touch of the hardness out of the floor and makes it warmer to walk on.
Smoothing the subfloor — it evens out very minor imperfections so the planks click together cleanly.

Why it isn't optional

Laying laminate straight onto a bare subfloor is a false economy. Without underlay you risk moisture reaching the core, a noticeably louder and harder floor, and click joints that don't sit as cleanly. Most laminate warranties also expect a suitable underlay to be used. It's a small part of the overall cost for a big improvement in how the floor lives.

How to choose the right underlay

Over concrete? Prioritise an underlay with a built-in moisture barrier (or lay a separate damp-proof membrane first).
Upstairs or in an apartment? Choose an acoustic underlay rated to reduce impact sound — your downstairs neighbours will thank you.
Want comfort and warmth? A slightly thicker underlay adds a softer, warmer feel — but don't go too thick, as too much give can stress the click joints over time.

Match the underlay to your subfloor and your room, and don't overthink it beyond that.

Fitting it

Underlay rolls out quickly: lay it across the subfloor with the seams butted (not overlapped) and taped, trim to the walls, then lay your laminate on top. It's the first thing you do once the subfloor is prepped — see the full process in our laminate installation guide.