UnderBlock™ Rubber Floor Underlayment

Substantially increase IIC and STC ratings of any floor-ceiling assembly with UnderBlock. Stop footsteps and easily hit building code requirements!

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UnderBlock Rubber Flooring Underlayment

It's a bird! It's a plane! No... it's UnderBlock! The floor soundproofing solution that will give a wedgie to footfall noise and a giant uppercut to airborne noise passing through your floor-ceiling assembly. Don't let a noisy upstairs ruin your day. Bring in some super help with an UnderBlock flooring upgrade. 


Product Information

  • Subflooring / underlayment for reducing impact noise, airborne noise, and vibration
  • 90% recycled rubber and 10% poly-binder
  • Compatible with most floor finishes and assemblies (tile, hardwood, laminate, or carpet)
  • Excellent improvement in STC ratings (airborne noise), FIIC and IIC ratings (impact noise) --- 50 to 70+ for both depending on specific construction
  • Easy roll out installation
  • Proudly made in the USA

For LEED certified projects, UnderBlock is both recycled and made in the USA.


 Roll Thickness   Roll Size   Weight   6" Concrete IIC 
 (LVT, No Ceiling) 

 6" Concrete Delta IIC 
 (LVT, No Ceiling)

 6" Concrete IIC 
 (Wood, No Ceiling) 

 6" Concrete Delta IIC 
 (Wood, No Ceiling)

2mm  4' x 50'  75 51 22 55 23
5mm  4' x 25'  85 54 24 55 23
10mm  4' x 15'  100 55 25 55 23
12mm  4' x 15'  120 56 26 55 23

UnderBlock - 10mm

  • Recommended for most soundproofing applications due to excellent IIC and STC improvement
  • With wire hung ceiling, IIC is 65+ an STC is 60+ depending on floor-ceiling assembly

UnderBlock - 12mm

  • Recommended for open joist ceilings and extreme soundproofing applications


 Spec Sheet 

 UnderBlock Product Sheet 

 Architect CSI Specs 

 UnderBlock CSI Spec 


Product Uses

  • Homes, apartments, home studios, recording studios, condos, hotels, conference rooms, offices, music practice rooms, band rooms, houses of worship, hospitals, malls, retail stores, theaters, schools, restaurants, and bars
  • If you've got a floor, UnderBlock will make it a soundproof floor. UnderBlock rubber underlayment stops all impact noise while also blocking airborne noise.
  • For heated floors, select a thinner version of UnderBlock for impact noise reduction with minimal thermal resistance.
  • The floor's soundproofing should be considered equally along with soundproofing walls and ceiling sound insulation when deciding how to soundproof a room.
  • To completely treat all 6 surfaces in thee room, sound proof doors and sound proof windows will be needed for any rough openings.


Installation Instructions

  • Roll out UnderBlock to cover the subfloor. Adhesive is optional. UnderBlock is heavy and will not move around.
  • Use a metal straight edge to make any cuts with a sharp utility knife.
  • Leave a 1/8" gap between UnderBlock and any obstacles (walls, columns, posts, drains, pipes, etc). Fill this gap with acoustic sealant caulk.
  • For perimeter walls, you can run UnderBlock directly to or under the wall instead of leaving the 1/8" gap and sealing it.
  • Roll out the UnderBlock in rows, keeping the factory seams tight and flush. If the seams are flush, acoustic sealant is not needed. Joints and seams can be taped if desired.
  • Install your chosen flooring on top of UnderBlock rubber flooring underlayment. For ceramic tile or sheet vinyl flooring, upgrade to UnderBlock HD or use an additional wood layer over the UnderBlock rubber underlayment.


If you have any questions about your type of flooring for your project, call us and we can walk you through it!

  • Floating floors do not require additional adhesive. They just lay on top of UnderBlock.
  • Mechanically fastened floors (nail down) should have a subfloor glued to the top of UnderBlock. Use our recommended rubber adhesive when required.
  • Glue down floors should use whatever adhesive is recommended by the flooring manufacturer that is compatible with attaching to rubber.


For large construction jobs with specific IIC requirements, contact us for additional information.




Project Category:
Material Type:
Room Soundproofing