You've picked out your laminate or floating hardwood. You've measured the room twice. You're ready to hit "add to cart" — and then you hit the underlayment section and wonder: does this actually matter, or is it just an upsell?
It matters. A lot. And if you're looking at Mohawk Platinum underlayment, here's an honest breakdown of what you're actually getting — and whether it's the right call for your project.
What Underlayment Actually Does (Quick Recap)
Before we get into Platinum specifically, it's worth understanding what underlayment is doing under your floor every day:
- Sound absorption — It cushions impact noise (footsteps, dropped items) and reduces the hollow "tap tap" sound that cheap underlayment causes with laminate
- Moisture protection — It acts as a barrier between your subfloor and your flooring, critical on concrete slabs or in moisture-prone rooms
- Subfloor smoothing — It compensates for minor dips and imperfections in your subfloor surface
- Thermal insulation — It adds an R-value layer that makes floors warmer underfoot in cooler months
- Floor stability — It supports the locking joints of floating floors, extending their lifespan
Cheap underlayment does some of these things, poorly. Better underlayment does all of them, well. That's where Mohawk Platinum comes in.
What Makes Mohawk Platinum Different
Mohawk Platinum (SKU: LU39) is a 3mm fanfold underlayment made in the USA, designed specifically for laminate and floating hardwood floors. Here's what sets it apart:
1. Superior Sound Performance
Platinum carries an IIC rating of 71 and an STC rating of 66, with a Delta rating of 21. In plain terms: it's engineered to mimic the sound of solid hardwood underfoot. That hollow, plasticky tap that drives people crazy with cheap laminate installs? Platinum is specifically designed to eliminate it. If you're installing in a multi-level home, condo, or any space where foot traffic noise is a concern, this rating matters.
2. Built-In Moisture Barrier
Platinum includes a pre-attached 1 mil moisture barrier — no separate vapor barrier roll needed. This is a meaningful time and money saver during installation, and it protects your floor from moisture wicking up through the subfloor. It's approved for use with Uniclic locking floor systems.
3. 3mm Thickness with 2.5mm Subfloor Smoothing
At 3mm thick, Platinum provides real cushioning. But the more important spec is the 2.5mm smoothing capability — meaning it can compensate for minor subfloor imperfections without you having to grind or skim-coat. For DIYers working with real-world subfloors (which are rarely perfect), this is a significant practical advantage.
4. Thermal Insulation (R-Value 0.53)
That's a meaningful R-value for an underlayment. If your floors feel cold in winter — particularly over a concrete slab or above a crawl space — Platinum's insulation layer makes a noticeable difference in comfort underfoot.
5. Fanfold Format = Fast Installation
Platinum ships in a fanfold format (48" wide x 25' long, 100 sq ft per pack), which unfolds cleanly across the room without rolling or fighting with the material. For DIYers, this speeds up the installation considerably compared to roll underlayments.
6. Made in the USA
For buyers who care about domestic manufacturing, Platinum is produced in the United States.
Who Should Choose Mohawk Platinum?
Platinum is the right call if any of these apply to your project:
- You're installing over concrete — The moisture barrier is essential, and Platinum's built-in protection saves you a step
- You want floors that sound like real hardwood — The IIC 71 rating delivers a genuinely solid feel underfoot
- Your subfloor has minor dips or imperfections — The 2.5mm smoothing gives you real forgiveness without extra prep work
- You're in a multi-story home or condo — Sound transmission between floors is a quality-of-life issue; Platinum's STC 66 handles it
- You want a warm, comfortable floor year-round — The R-0.53 thermal value is noticeable, especially in colder climates or over unheated spaces
How It Compares to Other Mohawk Underlayment Options
Not every project needs Platinum. Here's a quick comparison to help you calibrate:
| MositureGuard | Platinum LU39 | RealSound | |
| Best For | Moisture-prone installs | All-around premium performance | Sound-sensitive spaces |
| Thickness | Varies | 3mm | Varies |
| IIC Rating | Basic | 71 | Higher acoustic focus |
| Moisture Barrier | Yes (primary feature) | Yes (built-in) | Standard |
| Subfloor | Limited | 2.5mm | Limited |
| Price Point | Mid | Premium | Premium |
If moisture is your only concern, MoistureGuard gets the job done at a lower price point. If sound is your only concern, RealSound is purpose-built for that. Platinum is the right choice when you want all three — moisture protection, sound performance, and subfloor smoothing — in a single product.
The Real Cost Calculation
Here's how to think about the value:
Mohawk Platinum runs approximately $0.90–$1.00 per square foot, depending on where you purchase. For a 400 sq ft room, that's roughly $360–$400 for underlayment.
Compare that to the cost of:
- Fixing a moisture-damaged floor: $2,000–$8,000+
- Subfloor leveling compound: $50–$200+ depending on scope
- Sound complaints in a condo building: Priceless (and potentially lease-threatening)
The underlayment is almost never the place to cut corners. When you're already spending $2–$6+ per square foot on laminate or floating hardwood, adding a high-performance underlayment adds roughly 15–25% to your material cost while dramatically protecting the other 75–85%.
Bottom Line
Is Mohawk Platinum worth the upgrade? Yes — for most laminate and floating hardwood installs, it's the right choice.
It combines the three things homeowners care most about — sound quality, moisture protection, and floor stability — into a single, easy-to-install product that's backed by Mohawk's manufacturing standards.
If you're doing a full install and want floors that feel, sound, and perform like the real thing for years to come, Platinum is where the value is.
Ready to add Mohawk Platinum to your order? Shop Mohawk Platinum LU39 Underlayment here — available by the box.
