Do I Need Underlayment for Laminate Flooring?

Short answer: almost always yes

Underlayment goes between subfloor and floating laminate. It cushions, reduces noise, smooths minor subfloor texture, and often provides the required vapor barrier on concrete.

Skipping underlay voids many warranties and makes floors loud and hollow-sounding.

Types of underlay

Never stack two soft underlays unless the manufacturer explicitly permits it — too much flex breaks click locks.

• Foam (basic): 2–3 mm, budget rooms, smooth plywood subfloor
• Foam + vapor barrier (combo roll): required on concrete slabs in most regions
• Felt / fiber: denser, better sound — good for condos and second floors
• Cork: natural sound dampening, moderate moisture resistance
• Attached pad on plank: some laminates include factory pad — no second layer unless spec allows

Concrete vs wood subfloor

On concrete: use underlay with built-in 6 mil vapor barrier or separate poly sheet per local code. Test slab moisture first.

On plywood: standard foam or felt; vapor barrier usually not needed unless over crawl space with humidity.