The underlay for laminate flooring (also called underlayment) is a thin layer of material installed between the subfloor and the laminate planks. It is easy to overlook, but underlayment plays a critical role in how your laminate floor sounds, feels, and performs. The right underlayment reduces hollow sound, smooths minor subfloor imperfections, blocks moisture, and adds cushion underfoot. The wrong one — or no underlayment at all — leads to noisy, uncomfortable floors that may develop moisture damage over time.
- Why Laminate Flooring Needs Underlayment
- Types of Underlayment for Laminate
- 1. Standard Foam (Polyethylene)
- 2. Foam with Vapor Barrier (Combination)
- 3. Cork Underlayment
- 4. Rubber Underlayment
- 5. Felt Underlayment
- Thickness Guide
- Sound Ratings Explained
- When You Need a Moisture Barrier
- Underlayment With Attached Pad
- Top Underlayment Products for Laminate
- 1. QuietWalk — Best Overall
- 2. Floor Muffler UltraSeal — Best for Sound
- 3. Roberts Super Felt — Best Budget Premium
- 4. Roberts Harmony — Best Budget Option
- 5. AcoustiCORK — Best Cork Option
- Master Product Comparison Table
- Installation Tips
- Cost Guide
- Frequently Asked Questions
- What is the best underlay for laminate flooring?
- Do I need underlayment if my laminate has an attached pad?
- Can I use carpet padding under laminate?
- How thick should underlayment be for laminate?
- Do I need a vapor barrier under laminate?
- What happens if I install laminate without underlayment?
- Is cork or foam underlayment better for laminate?
- Can I reuse underlayment when replacing laminate?
This guide compares every type of underlay for laminate flooring, explains thickness and sound ratings, covers moisture barrier requirements, reviews top products, and helps you choose the right underlayment for your project.
Why Laminate Flooring Needs Underlayment
Laminate flooring is installed as a floating floor — it sits on top of the subfloor without being nailed or glued down. This means there is a gap between the subfloor and the laminate planks. Without underlayment filling that gap, you get several problems:
- Noise: Laminate on a bare subfloor produces a loud, hollow clacking sound with every step. Underlayment absorbs impact noise and dampens the sound.
- Comfort: Underlayment adds a thin cushion layer that makes the floor more comfortable to walk and stand on.
- Subfloor imperfections: Minor bumps, dips, and unevenness in the subfloor telegraph through thin laminate. Underlayment bridges small imperfections (not a substitute for proper subfloor leveling).
- Moisture protection: Concrete subfloors release moisture vapor that can damage laminate from below. Underlayment with a built-in vapor barrier blocks this moisture.
- Thermal insulation: Underlayment provides a slight insulating layer, making floors warmer underfoot — especially over concrete.
Nearly all laminate manufacturers require underlayment and will void the warranty if laminate is installed without it (unless the product has an attached pad).
Types of Underlayment for Laminate
1. Standard Foam (Polyethylene)
The most common and affordable option. Standard foam underlayment is a thin polyethylene sheet that provides basic cushioning and sound reduction.
- Thickness: 2 mm to 3 mm
- Sound reduction: Basic (STC 50-55, IIC 50-55)
- Moisture barrier: No (must add separate poly sheeting over concrete)
- Cost: $0.10 – $0.25 per sq ft
- Best for: Budget installations over wood subfloors
2. Foam with Vapor Barrier (Combination)
This is standard foam with an attached polyethylene film moisture barrier — the most popular underlayment for laminate flooring overall. It combines cushioning with moisture protection in one product.
- Thickness: 2 mm to 3 mm (plus film)
- Sound reduction: Moderate (STC 55-60, IIC 55-60)
- Moisture barrier: Yes (built-in poly film)
- Cost: $0.15 – $0.35 per sq ft
- Best for: Most installations, especially over concrete
3. Cork Underlayment
Cork is a premium natural underlayment that excels at sound absorption. It is denser and more effective than foam at reducing both impact noise (footsteps heard in the room) and transmission noise (sound traveling to rooms below).
- Thickness: 3 mm to 6 mm
- Sound reduction: Excellent (STC 60-65, IIC 60-70)
- Moisture barrier: Natural moisture resistance, but add vapor barrier over concrete
- Cost: $0.50 – $1.00 per sq ft
- Best for: Upper floors in multi-story homes, condos, noise-sensitive areas
4. Rubber Underlayment
Rubber provides the best sound deadening and vibration absorption of any underlayment material. It is the premium choice for multi-story buildings, condos with HOA sound requirements, and home theaters.
- Thickness: 2 mm to 5 mm
- Sound reduction: Superior (STC 65-73, IIC 65-73)
- Moisture barrier: Naturally moisture-resistant
- Cost: $0.75 – $1.50 per sq ft
- Best for: Condos, apartments, home theaters, sound-critical applications
5. Felt Underlayment
Felt underlayment is made from recycled fibers compressed into a dense, durable pad. It provides excellent sound absorption and thermal insulation, with performance between cork and rubber.
- Thickness: 3 mm
- Sound reduction: Very good (STC 60-66, IIC 60-68)
- Moisture barrier: Some products include a film; others do not
- Cost: $0.40 – $0.80 per sq ft
- Best for: Premium installations, sound reduction, thermal comfort
| Type | Sound Reduction | Moisture Barrier | Comfort | Cost (per sq ft) | Best For |
|---|---|---|---|---|---|
| Standard foam | Basic | No | Basic | $0.10 – $0.25 | Budget, wood subfloor |
| Foam + vapor barrier | Moderate | Yes | Basic | $0.15 – $0.35 | Most installations |
| Cork | Excellent | Partial | Good | $0.50 – $1.00 | Multi-story, noise |
| Rubber | Superior | Yes | Very good | $0.75 – $1.50 | Condos, theaters |
| Felt | Very good | Varies | Good | $0.40 – $0.80 | Premium comfort |
Thickness Guide
Underlayment thickness matters — but more is not always better.
Recommended thickness for laminate: 2 mm to 3 mm for most installations. This provides adequate sound reduction, cushion, and imperfection bridging without creating an overly soft surface that causes the click-lock joints to flex and fail.
Maximum thickness: Most laminate manufacturers specify a maximum underlayment thickness of 3 mm. Exceeding this can void your warranty because the excess cushion allows too much plank deflection at the joints, which can break the locking mechanism over time.
| Thickness | When to Use | Notes |
|---|---|---|
| 1.5 – 2 mm | Laminate with attached pad (supplemental only) | Some laminates prohibit additional underlayment |
| 2 mm | Standard laminate over wood subfloor | Minimum recommended |
| 3 mm | Standard laminate over concrete or when sound matters | Most common choice |
| 4 – 6 mm | Only if manufacturer specifically allows | May void warranty on many products |
Important: Always check your laminate manufacturer’s underlayment specifications before purchasing. Some brands allow up to 3 mm; others may specify exactly 2 mm. Never stack two layers of underlayment — this always voids the warranty.
Sound Ratings Explained
Underlayment sound performance is measured by two ratings:
STC (Sound Transmission Class): Measures how well the underlayment blocks airborne sound (voices, music) from passing through the floor assembly. Higher is better. STC 50+ is considered adequate; STC 65+ is excellent.
IIC (Impact Insulation Class): Measures how well the underlayment absorbs impact noise (footsteps, dropped objects) from being heard in the room below. Higher is better. IIC 50+ is standard; IIC 65+ is premium.
| Rating | STC Range | IIC Range | Performance Level |
|---|---|---|---|
| Budget foam | 50 – 55 | 50 – 55 | Acceptable |
| Foam + vapor barrier | 55 – 60 | 55 – 60 | Good |
| Cork | 60 – 65 | 60 – 70 | Very good |
| Felt | 60 – 66 | 60 – 68 | Very good |
| Rubber | 65 – 73 | 65 – 73 | Excellent |
Condo and apartment note: Many HOA rules require a minimum IIC rating of 60 or 65 for upper-floor installations. Check your building’s requirements before choosing underlayment. Cork, felt, or rubber will be necessary to meet these thresholds.
When You Need a Moisture Barrier
A moisture barrier (vapor barrier) prevents moisture vapor from the subfloor from reaching the bottom of your laminate planks. Moisture from below causes laminate to swell, warp, and delaminate.
You need a moisture barrier if:
- Installing over concrete (ground level or below grade)
- Installing over a concrete slab, even on an upper floor
- Installing in a basement
- Moisture test readings are above 3 lbs per 1,000 sq ft (calcium chloride test)
You may not need a separate moisture barrier if:
- Installing over a plywood or OSB subfloor on an upper level
- Your underlayment already includes a built-in vapor barrier film
Options:
- Use underlayment with an integrated vapor barrier (most convenient)
- Lay 6-mil polyethylene sheeting over the subfloor, then install standard underlayment on top
For more on moisture considerations, see our laminate installation guide.
Underlayment With Attached Pad
Many premium laminate products now come with a factory-attached underlayment pad on the bottom of each plank. This eliminates the need for a separate underlayment roll.
Advantages:
- Faster installation (skip the underlayment step)
- Guaranteed compatibility with the laminate
- No risk of installing the wrong thickness
- Saves $0.25 – $0.75 per sq ft on separate underlayment
Important: If your laminate has an attached pad, do NOT install additional underlayment underneath. Double padding creates excessive cushion that damages click-lock joints. If you need a moisture barrier, use only a thin 6-mil poly sheeting — not foam underlayment.
See our complete underlayment guide for information on underlayment for all flooring types.
Top Underlayment Products for Laminate
1. QuietWalk — Best Overall
QuietWalk is a premium felt underlayment made from recycled fibers. It is the most recommended underlayment among flooring professionals for laminate installations. It delivers excellent sound absorption (STC 66, IIC 68), includes a built-in vapor barrier, and meets the strictest condo sound requirements.
- Material: Recycled felt fiber
- Thickness: 3 mm
- Sound: STC 66, IIC 68
- Vapor barrier: Yes (built-in)
- Price: $0.55 – $0.75 per sq ft
- Sold at: Home Depot, Lowe’s, Amazon
2. Floor Muffler UltraSeal — Best for Sound
Floor Muffler UltraSeal is a cross-linked polypropylene foam underlayment with an integrated moisture barrier. It achieves excellent sound ratings at a lower price than cork or rubber, making it a strong mid-range option.
- Material: Cross-linked polypropylene foam
- Thickness: 2 mm
- Sound: STC 73, IIC 74
- Vapor barrier: Yes (UltraSeal film)
- Price: $0.40 – $0.60 per sq ft
- Sold at: Floor & Decor, Amazon, specialty dealers
3. Roberts Super Felt — Best Budget Premium
Roberts Super Felt is a dense felt underlayment with sound-dampening performance similar to QuietWalk at a slightly lower price point. It includes a built-in vapor barrier and is approved for use with floating laminate, LVP, and engineered hardwood.
- Material: Recycled felt fiber
- Thickness: 3 mm
- Sound: STC 66, IIC 67
- Vapor barrier: Yes
- Price: $0.40 – $0.60 per sq ft
- Sold at: Home Depot, Lowe’s
4. Roberts Harmony — Best Budget Option
Roberts Harmony is a standard foam underlayment with an attached 6-mil poly moisture barrier. It delivers basic performance at the lowest cost and is a solid choice for budget laminate installations over concrete.
- Material: Polyethylene foam + poly film
- Thickness: 2 mm
- Sound: STC 56, IIC 55
- Vapor barrier: Yes
- Price: $0.15 – $0.25 per sq ft
- Sold at: Home Depot, Lowe’s
5. AcoustiCORK — Best Cork Option
AcoustiCORK is a natural cork underlayment that provides excellent sound insulation and thermal comfort. It is hypoallergenic, antimicrobial, and one of the most environmentally friendly underlayment options.
- Material: Natural cork
- Thickness: 3 mm and 6 mm
- Sound: STC 60, IIC 63 (3 mm); higher for 6 mm
- Vapor barrier: No (add poly sheeting over concrete)
- Price: $0.60 – $1.00 per sq ft
- Sold at: Amazon, specialty flooring retailers
Master Product Comparison Table
| Product | Material | Thickness | STC | IIC | Vapor Barrier | Price (per sq ft) |
|---|---|---|---|---|---|---|
| QuietWalk | Felt | 3 mm | 66 | 68 | Yes | $0.55 – $0.75 |
| Floor Muffler UltraSeal | Polypropylene foam | 2 mm | 73 | 74 | Yes | $0.40 – $0.60 |
| Roberts Super Felt | Felt | 3 mm | 66 | 67 | Yes | $0.40 – $0.60 |
| Roberts Harmony | PE foam | 2 mm | 56 | 55 | Yes | $0.15 – $0.25 |
| AcoustiCORK | Cork | 3 mm | 60 | 63 | No | $0.60 – $1.00 |
Installation Tips
- Roll out underlayment in the same direction you will lay the laminate planks.
- Butt seams — do not overlap. Overlapping underlayment creates a ridge that shows through the laminate. Butt edges tightly and tape the seams with underlayment tape.
- Overlap the vapor barrier film. If the underlayment has a built-in vapor barrier flap, overlap the film 6 to 8 inches at each seam and tape with moisture-barrier tape.
- Run underlayment 2 inches up the walls. Trim flush after the laminate is installed and before baseboards go on.
- Only install one row of underlayment at a time to avoid stepping on it and compressing it before laminate covers it.
- Never use two layers of underlayment. This voids virtually every laminate warranty.
For step-by-step laminate installation, see our laminate installation guide. For floating floor best practices, visit our floating floor resource.
Cost Guide
| Underlayment Type | Cost per Sq Ft | 500 Sq Ft Total | Notes |
|---|---|---|---|
| Basic foam | $0.10 – $0.25 | $50 – $125 | Add separate poly sheet for concrete |
| Foam + vapor barrier | $0.15 – $0.35 | $75 – $175 | Best value for most installs |
| Felt (QuietWalk, Roberts) | $0.40 – $0.75 | $200 – $375 | Best overall performance |
| Cork | $0.50 – $1.00 | $250 – $500 | Natural, excellent sound |
| Rubber | $0.75 – $1.50 | $375 – $750 | Premium sound deadening |
Underlayment typically adds $0.15 to $1.00 per square foot to your laminate project cost — a small investment for the significant improvement in sound, comfort, and moisture protection it provides. For a broader look at costs, see our laminate flooring guide.
Frequently Asked Questions
What is the best underlay for laminate flooring?
QuietWalk felt underlayment is the best overall choice for laminate. It provides excellent sound reduction (STC 66, IIC 68), includes a built-in vapor barrier, and is widely available. For budget projects, a foam underlayment with vapor barrier is adequate.
Do I need underlayment if my laminate has an attached pad?
No. If your laminate has a factory-attached pad, do not add separate underlayment — this doubles the cushion and can damage click-lock joints. If installing over concrete, lay only a thin 6-mil poly sheet for moisture protection.
Can I use carpet padding under laminate?
No. Carpet padding is too thick and soft for laminate flooring. It causes excessive plank deflection, which breaks click-lock joints and voids the warranty. Always use underlayment specifically designed for floating hard-surface flooring.
How thick should underlayment be for laminate?
2 mm to 3 mm is the standard range. Most laminate manufacturers specify a maximum of 3 mm. Never exceed the manufacturer’s recommendation or stack multiple layers of underlayment.
Do I need a vapor barrier under laminate?
Yes, if installing over concrete at any level. Concrete releases moisture vapor that can damage laminate from below. Use underlayment with a built-in vapor barrier or lay 6-mil poly sheeting over the concrete before installing standard underlayment.
What happens if I install laminate without underlayment?
The floor will be noticeably loud and hollow-sounding, uncomfortable underfoot, and may develop moisture damage (over concrete). It also voids most laminate warranties.
Is cork or foam underlayment better for laminate?
Cork is better for sound absorption and comfort but costs 3 to 5 times more than foam. Foam is adequate for most single-story installations. Cork is the better choice for upper floors, condos, or noise-sensitive situations.
Can I reuse underlayment when replacing laminate?
If the existing underlayment is in good condition (not compressed, torn, or moisture-damaged), you can reuse it. However, new underlayment is inexpensive and ensures optimal performance for the new flooring.
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