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Acoustical Underlayment System

61 STC / 55 IIC

Over Wood Framed Construction
No Flanking Paths
No Additional Treatments
No Smoke, No Mirrors


Treadstone Launches New Elite Duo Sound Attenuation System

The Treadstone Elite Duo acoustical system delivers an astounding 61 STC/55 IIC in a system with an unparalleled thickness of just over 1”.

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  • 33,000 lbs ft2 for 1mm of deflection
  • Overall system thickness of just over 1”
  • Ready for floor covering in 7-10 days
  • Reduces cooking smells and other odors between floors
  • Engineered for today’s modern vinyl plank floors

All acoustical testing was performed with a standard 2.5 mm unbacked vinyl plank to ensure consistent performance in every spec, and on every job. No additional treatments to the flooring assembly are required, including additional underlayment pour depth.

Elite Duo’s patent pending technology and unique two-component system eliminates flanking paths by providing seamless perimeter isolation. Our installation methodology allows for complete isolation of utility pipes and door sills, providing you with unparalleled real-world performance.

Elite Duo’s revolutionary open-face design represents  a breakthrough in Ultra-Rigid Noise Control. A new generation of underlayments, able to provide long-term performance beneath today’s LVT and LVP.  Fewer cracks, no adhesion failures, and no telegraphing in your vinyl floor.

Elite Duo Underlayment SystemCombining two new innovative technologies that provide unmatched acoustical performance and durability in a patent pending system. Treadstone Duo Elite’s industry leading deflection/compression innovation allows for Treadstone
underlayment depths of ¾” min. providing an overall thickness of just over 1”. Treadstone® Elite – Monolithic, rolled plastic core membrane comprised of polyethene and polypropylene, in a high compression resistance cuspated
HDPE design. Provides compression/deflection resistance never seen in an acoustical sound mat product.

Treadstone® Elite Benefits:

  • Light / flexible for easy installation
  • 33,000lbs per sf for 1mm of deflection
  • UL Listed in 117 designs
  • Can increase IIC values up to 10db in wood framed construction
  • Reduced underlayment thickness allows for faster underlayment drying time. Ready for floor covering in 7-10 days

Treadstone® Duo – Needle punched non-woven polyester fabric technology
that provides the systems base layer increasing the low frequency benefit.
Due to is flexible properties, Duo can be run up walls and serve as the
perimeter isolation strip, thus eliminating leaks
(flanking paths) due to tape failure or improper installation practices.


  • Specifically designed to achieve greater low frequency performance.
  • Light / Flexible for easy installation
  • UL Listed 117 designs
  • 100% recycled polyester fibers
  • LEED Credits; Materials and Resources – MR 3, MR 4, MR 5, MR 6; Indoor Environmental Quality IEQ 1, IEQ 2; Innovation and Design
    Process – IDP 1

Acoustical Performance

Testing Assembly:

  • 18″ Truss Joist, 24″ O.C.
  • T&G Deck,
  • Single Layer Batt Insulation
  • RC-1
  • 5/8″ Ceiling Board
  • 3/4 Treadstone® Underlayment
TREADSTONE® Sound Attenuating MatFinished Floor CoveringSTCIIC
Wood Laminate49
Wood Laminate55
Elite DuoVinyl6155
Wood Laminate56

Typical Physical Properties


Physical Properties:
• Weight: .086 lbs per sf
• Thickness: .19 in. (3/16”)
• Width: 3.75’
• Length: 160’
• SF per roll: 600
• Roll weight: 52 lbs
• Rolls per pallet: 8 rolls


Physical Properties
• Density: 15.83 lb./ft3
• Roll Size: 4′ x 150′
• Area covered / roll: 600 sf per roll
• Thickness: .0984 in. (3/32 in.)
• Weight / roll: 47 lb.
• Rolls per pallet: 6 rolls



Clean, remove all foreign matter from surface. Surface must be dry.


Treadstone® Elite Duo Sound Attenuating System is to be installed by a qualified Treadstone® Dealer. The building must be closed in with a minimum of 50 degrees F, maintained for a period of 5-7 days during and after the installation of Treadstone® Elite and Treadstone® Underlayment. Duo is loose laid on the subfloor with seams tightly abutting. Duo will extend up the perimeter walls by at least 2” to provide seamless perimeter isolation and may be affixed to walls using an approved fastener above underlayment pour depth. All seams on abutting edges of Duo that will be exposed to the underlayment should be sealed with an approved tape to avoid flanking paths.

Elite is then loose laid on the Duo with all seams running perpendicular to the Duo underlayment whenever possible. Parallel seams should never be placed directly above existing seams in the Duo application. All parallel seams should be staggered by a minimum of 3”. All abutting seams of Elite should be tightly joined and sealed using Treadstone® Soundmat Tape.


Store in dry conditions.


  • Treadstone® Elite Duo is only one component of the floor ceiling assembly and overall noise reduction strategy. While using Treadstone® Elite Duo will improve the overall acoustics performance of the assembly, the exact amount or minimum performance cannot be guaranteed. Formulated Materials recommends contacting an acoustical consultant for recommendations regarding the acoustical performance of any and all projects.
  • To minimize risk of damage to the Treadstone® Underlayment, installation of Elite Duo and underlayment is recommended after drywall.    For installation prior to drywall, contact Formulated Materials for recommendations.
  • Treadstone® Underlayment thickness/compressive strength recommendations
    •    Residential/Multifamily Construction: .75” (38mm) at 2,000 psi minimum
    •    Light Commercial: .75” (38mm) at 3,000psi minimum

UL Designs

G230 G516 G524 G561 G577 G578 G579 G580 G581 G582 G587 G592


J917 J919 J920 J924 J927 J931 J957 J958 J991 J994

L006 L201 L202 L206 L209 L210 L211 L212 L501 L502 L503 L504 L505 L506 L507 L508 L509 L510 L511 L512 L513 L514L515  L516 L517 L518 L519 L520 L522 L523 L524 L525 L526 L527 L528 L529 L530 L532 L533 L534 L535 L536 L537 L538 L539 L540 L541 L542 L543 L545 L546 L549 L550 L551 L552 L556 L557 L558 L560 L562 L563 L565 L570 L573 L574 L576 L577 L579 L581 L583 L585 L587 L588 L589 L590 L592 L593

M500 M502 M503 M504 M506 M508 M511 M512 M513 M515 M517 M519 M530 M531 M535 M536