Best Underlayment for Vinyl Plank Flooring: What to Use (and What to Avoid)

Choosing the right underlayment for vinyl plank flooring is one of those details that separates a professional-feeling floor from one that sounds hollow, feels hard, and develops problems within a year. The wrong underlayment can void your warranty, cause planks to separate, and create a floor that clicks and pops with every step.

This guide covers when you actually need underlayment for LVP flooring, the best products for different situations, and the critical mistakes to avoid.

Do You Actually Need Underlayment for LVP?

Not always. Many luxury vinyl plank products come with an attached pad (also called an integrated or pre-attached underlayment). If your LVP already has a pad on the bottom of each plank, adding a separate underlayment on top of that can cause problems.

When You Need Separate Underlayment

• Your LVP has no attached pad: This is the primary reason. Budget and mid-range LVP products often ship without padding. Installing them directly on a hard subfloor will feel harsh underfoot and sound hollow.
• Concrete subfloor: Even if your LVP has an attached pad, concrete subfloors typically require a separate moisture barrier (6-mil polyethylene sheeting) unless the attached pad includes one.
• Sound control requirements: Apartments, condos, and upper floors often have sound transmission requirements (STC/IIC ratings) that the attached pad alone cannot meet.
• Minor subfloor imperfections: Underlayment can smooth out very minor unevenness (less than 1/8 inch). However, it is not a substitute for proper subfloor leveling.

When You Do NOT Need Separate Underlayment

• Your LVP has an attached pad with moisture barrier: Adding extra underlayment creates too much cushion, making the locking system unstable.
• Glue-down LVP: Glue-down vinyl planks require direct contact with the subfloor. Underlayment prevents proper adhesion.
• Manufacturer says not to: Always check the installation instructions. Many LVP brands explicitly prohibit certain underlayment types and will void the warranty if you use them.

Best Underlayment Products for Vinyl Plank Flooring

Here are the top-performing underlayment products specifically designed or approved for use with floating vinyl plank floors.

Detailed Product Reviews

QuietWalk Luxury Vinyl Underlayment

QuietWalk is the most widely recommended underlayment for vinyl plank flooring and for good reason. Made from recycled fiber, it provides excellent sound absorption (STC 66/IIC 71), a built-in moisture vapor barrier, and just enough cushion without being too soft for click-lock LVP systems.

The fiber construction also provides slight thermal insulation and allows the subfloor to breathe, which helps prevent moisture problems on concrete. QuietWalk is approved by most major LVP manufacturers and will not void your warranty.

Pros: Best overall balance of sound, moisture, and comfort. Approved by most LVP brands. Made from recycled materials.

Cons: More expensive than basic foam underlayment. Slightly thicker profile may require transition strip adjustments.

Floor Muffler LVT

If sound reduction is your primary concern, Floor Muffler LVT delivers the highest STC and IIC ratings in this category. It is specifically engineered for luxury vinyl flooring and features a cross-linked polypropylene foam construction with an integrated moisture barrier.

Floor Muffler is particularly popular in multi-story buildings where sound transmission between floors must meet building code requirements (typically IIC 50 minimum).

Pros: Best-in-class sound reduction. Integrated moisture barrier. Excellent for condos and apartments.

Cons: Most expensive option on this list. May be overkill for single-family homes on ground-level concrete.

Floorlot Blue LVT Underlayment

Floorlot Blue provides solid performance at a budget-friendly price. It includes a built-in moisture barrier, adequate sound reduction, and works well under most floating LVP products. For homeowners who need basic underlayment without premium pricing, this is the best value.

Pros: Lowest price with integrated moisture barrier. Adequate sound reduction. Easy to install.

Cons: Lower STC/IIC ratings than QuietWalk and Floor Muffler. Thinner foam may compress over time in high-traffic areas.

Underlayment Thickness: Why It Matters for LVP

Thickness is a critical consideration for vinyl plank underlayment, and more is definitely not better.

The Goldilocks Zone: 1 mm to 1.5 mm

Vinyl plank flooring uses a click-lock system that relies on a firm, stable surface underneath. If the underlayment is too soft or too thick, the planks flex underfoot, which stresses the locking mechanism and eventually causes gaps, separations, and clicking noises.

• 1 mm: The minimum effective thickness. Provides basic cushion and sound reduction on wood subfloors.
• 1.4 to 1.5 mm: The sweet spot. Enough cushion for comfort and sound absorption without compromising the locking system stability.
• 2 mm and above: Generally too thick for vinyl plank. This much cushion causes the planks to flex, leading to joint failure. Some manufacturers void warranties with underlayment over 1.5 mm.

Combined Thickness Rule

If your LVP has an attached pad, the total combined underlayment thickness (attached pad plus separate underlayment) should typically not exceed 2 mm. Adding a 1.5 mm underlayment beneath planks with a 1 mm attached pad creates 2.5 mm of cushion, which is almost always too much.

Moisture Barrier: When You Need One

A moisture barrier prevents water vapor from passing through the subfloor and reaching the underside of your vinyl plank flooring. Excess moisture can cause mold, mildew, and adhesion problems.

Concrete Subfloors: Always Need a Moisture Barrier

All concrete subfloors emit moisture vapor, even fully cured concrete. Whether your concrete is on a slab-on-grade (ground level) or in a basement, you need a moisture barrier. Options include:

• Underlayment with built-in moisture barrier: The easiest solution. Products like QuietWalk, Floor Muffler, and Floorlot Blue include integrated vapor barriers.
• Separate 6-mil poly sheeting: Roll out 6-mil polyethylene sheeting over the concrete, overlapping seams by 8 inches and taping them. Then install your underlayment on top.

Wood Subfloors: Usually Do Not Need a Moisture Barrier

Plywood and OSB subfloors on upper levels generally do not need a moisture barrier. In fact, trapping moisture between a wood subfloor and a vapor barrier can cause the wood to rot. On wood subfloors above crawl spaces, address moisture at the crawl space level instead.

Sound Reduction: Understanding STC and IIC Ratings

If you live in a condo, apartment, or multi-story home, sound transmission through the floor matters. Two ratings measure this:

• STC (Sound Transmission Class): Measures airborne sound transmission (voices, music, television). Higher numbers are better. Most building codes require STC 50 minimum between dwelling units.
• IIC (Impact Insulation Class): Measures impact sound (footsteps, dropped objects). Higher numbers are better. Most building codes require IIC 50 minimum between dwelling units.

LVP on its own has poor sound performance. Without underlayment, a floating vinyl plank floor over concrete typically rates around STC 45 to 50 and IIC 35 to 45, which may not meet code requirements in multi-family buildings.

What NOT to Use Under Vinyl Plank Flooring

Using the wrong underlayment is worse than using none at all. These are the most common mistakes that cause LVP failures.

Thick Carpet Pad

This is the most common mistake, especially with DIYers who have leftover carpet padding. Carpet pad is far too thick and soft for vinyl plank flooring. The planks will flex dramatically with every step, the click-lock joints will separate within weeks, and the floor will feel unstable and spongy. Never use carpet pad under LVP.

Cork Underlayment Over 1.5 mm

While thin cork (1 mm) can work under some LVP products, thicker cork underlayment is too compressible. Cork also absorbs moisture, which can be a problem on concrete subfloors without a separate vapor barrier.

Standard Laminate Flooring Underlayment

Many foam underlayment products are designed for laminate flooring, not vinyl plank. Laminate flooring is more rigid than LVP and can tolerate thicker, softer underlayment. Using standard laminate underlayment under LVP often provides too much cushion.

Two Layers of Underlayment

If your LVP has an attached pad, do not add a second layer of underlayment on top. The combined thickness creates excessive flex. If you need a moisture barrier on concrete, use thin 6-mil poly sheeting, not another full underlayment layer.

Concrete vs. Wood Subfloor: Underlayment Recommendations

How to Install Underlayment for Vinyl Plank

Installing underlayment is straightforward, but proper technique ensures the best results.

1. Clean the subfloor: Sweep and vacuum thoroughly. Any debris under the underlayment creates bumps that telegraph through the vinyl planks.
2. Check subfloor flatness: Lay a 10-foot straightedge across the floor. No deviation should exceed 3/16 inch. Fill low spots with leveling compound and sand or grind high spots.
3. Roll out the underlayment: Start along one wall and roll out the first strip. Butt the edges together without overlapping (unless the product specifically instructs overlapping for the moisture barrier flap).
4. Tape the seams: Use the product’s recommended tape (many include an adhesive overlap strip) to seal seams and prevent them from shifting during LVP installation.
5. Trim to fit: Cut the underlayment to fit around obstacles with a utility knife. Do not leave gaps at walls.
6. Install only one row ahead: Roll out underlayment just a few feet ahead of your LVP installation to prevent it from being damaged by foot traffic during installation.