Should I Use Underlayment For Vinyl Plank Flooring?

When It Makes Sense

• Good fit: Installing vinyl plank over a concrete slab that has no built‑in moisture barrier. An underlayment with a vapor‑retardant layer helps protect the planks from upward moisture and adds a cushion.
• Good fit: Adding vinyl plank to a room with radiant floor heating. A thin, heat‑compatible underlayment can improve thermal transfer while reducing noise and minor subfloor imperfections.

When You Should Avoid It

• Warning sign: The flooring manufacturer specifies a “no‑underlayment” installation. Ignoring that guidance can void the warranty and affect product performance.
• Warning sign: The subfloor is already a high‑quality, engineered underlayment (e.g., a floating wood subfloor) that provides sufficient padding and moisture control. Adding another layer may create height issues and a soft feel.

Pros and Cons

Pros

• Improved comfort and reduced footfall noise, especially in multi‑room apartments or homes with hardwood below.
• Additional moisture barrier can safeguard the vinyl planks from subfloor moisture, extending the floor’s lifespan.

Cons

• Added material cost and installation time; low‑budget projects may feel the extra expense.
• Incorrectly chosen underlayment (e.g., too thick, non‑compatible with heat) can affect click‑lock mechanisms or reduce heating efficiency.

Decision Checklist

• Does the vinyl plank manufacturer recommend or require an underlayment for your specific product?
• Is the existing subfloor prone to moisture transmission or unevenness that an underlayment would address?
• Will the added thickness affect door clearances, transitions, or the overall floor height in a way that creates additional work?

Alternatives to Consider

If you decide against a separate underlayment, you can look for vinyl planks that come with pre‑attached underlayment, or use a moisture‑resistant sealant on the concrete before installation. In some cases, a thin, high‑density backer board can replace a traditional roll underlayment while providing a stable surface.

Final Recommendation

Use an underlayment when the subfloor lacks built‑in moisture protection, when you need extra cushioning, or when the flooring brand advises it. Skip it if the product explicitly says not to use one or if an existing high‑quality underlayer is already present. Always verify the manufacturer’s installation guidelines and, for complex subfloors or heated systems, consult a flooring professional.