What is the best underlay for laminate over concrete?

Choosing the best underlay for installing laminate on a concrete subfloor is a important choice. The underlay must protect your floor from moisture damage including mold and mildew.

Laminate Floors:

Laminate is a floating floor, which means it needs something between it and the concrete. That “something” is the underlay.  Choosing the wrong type of underlay can make or break your installation. 

What is the Role of Underlay Over Concrete?

Underlay isn’t just there for show or small add on at the store, it has a vital role for installation including:

  • Blocking moisture from the concrete subfloor
  • Help stop the sound of clicking between the laminate and concrete
  • Add warmth to cold floors

Choosing the Best Option

The right choice depends on:

  • Location: Basements and slab-on-grade floors benefit the most from a dimpled subfloor membrane. 
  • Moisture Risk: Does your underlay allow your floor to breath or will moisture get trapped against your flooring?
  • Comfort Needs: Will your underlay help warmth and noise reduction matter, look for an option that insulates as well as protects.

Comparing Typical Underlay Materials

1. Plastic Poly Vapor Barrier sheet (6 mil or thicker)

✅ Budget-friendly
❌ No cushion, warmth, or sound absorption
❌ Must be perfectly sealed at seams and edges
❌ Offers no airflow to help moisture escape

2. Foam Underlay with Built-in Vapor Film

✅ Slight cushioning, easy to roll out and install
✅ Built-in moisture film for basic protection
❌ Limited moisture resistance, not ideal for damp or below-grade spaces
❌ Won’t address concrete coldness or hollow floor sound

3. Dimpled Subfloor System (Underlay + Air Gap)

✅ HDPE core provides a permanent barrier against moisture
✅ The air Gap allows air circulation to help evaporate trapped moisture
✅ Provides a thermal break for warmer floors
✅ Reduces the hollow sound common with laminate on concrete

Unlike flat foam or a poly plastic sheet, SUPERSEAL All-In-One Subfloor has a dimpled air gap on both sides creating a drainage space and air gap that lets moisture evaporate without damaging your floor. 

In Summary

If you want your laminate to stay flat, dry, and comfortable for years, the right underlay matters. Having a dimpled membrane will always be better than a foam underlay on concrete. Being cheap here can cause health concerns and costly repairs later.

Back to FLOORING 101 – Installing Laminate on Concrete