Underlayment installation answer

Cork underlayment installation

Cork underlayment installation starts with a clean, flat, dry substrate, then matching the 3mm, 6mm, or 12mm cork layer to the finished floor, sound goal, moisture limits, and approved installation method.

  • Compare 3mm, 6mm, and 12mm cork underlayment before choosing the full project layer.
  • Confirm the finished floor allows cork underlay under hardwood, laminate, vinyl, tile, or cork.
  • Use samples and specialist help to confirm thickness, finished height, and acoustic expectations.
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Cork Underlayment Installation

If your HOA requires a specific IIC or STC rating, begin with the building rules and the existing floor-and-ceiling assembly. We can provide product test reports for your review.

Confirm whether the building uses wood framing or a concrete slab, including the slab thickness. Those details affect the finished assembly rating.

A target rating cannot be evaluated without the building’s existing assembly and test method.

Download the supporting documents below and provide them to your HOA or property manager.

1/2″ (12mm) cork underlayment IIC STC statement.

1/4″ (6mm) cork underlayment IIC STC statement.

1/8″ (3mm) cork underlayment IIC STC statement.

1/2″ (12mm) cork floating IIC report.

 

A note on the numbers below: sound ratings are not additive in real buildings — the finished IIC/STC result always depends on your specific structure (joist spacing, slab thickness, the ceiling below). The per-product figures in each solution come from our test statements; treat them as what each component contributes, and ask your HOA or property manager for the building’s existing rating. The test documents for every product are linked above and in the HOA Flooring Approval Kit.

Solution for wood frame building 1:

  • Wood frame building offers 25 dB worth of insulation
  • Add ¼”(6mm) cork underlay =23 dB
  • Forna ½”(12mm) cork floating flooring = 22 dB

 

Solution for wood frame building 2:

  1. Wood frame building offers 25 dB worth of insulation
  2. Add 1/2” (12mm) cork underlay = 48 dB
  3. Other flooring such as engineer hardwood, Vinyl = (0dB)

Compare products using reports that identify the complete tested assembly. A product-only figure does not predict the final result in every building.

 

Solution for 2.5” concrete slab construction building:

  1. 5” concrete slab construction building = 11.25 dB (for the concrete slab)
  2. Add 1/2” (12mm) cork underlay = 48 dB
  3. Add 1/2″ (12mm) cork floating flooring that has 22 dB.

 

Solution for 2.5” concrete slab construction building 2:

  1. 5” concrete slab construction building = 11.25 dB for the concrete slab)
  2. Add 1/4″ (6mm) cork underlayment = 23dB
  3. Add 1/2″ (12mm) cork floating flooring that has 22dB.

 

Solution for 6” concrete slab construction building: 

  1. 6” concrete slab construction building = 27 dB for the concrete slab)
  2. Add 1/4″ (6mm) cork underlayment = 23dB
  3. Add 1/2″ (12mm) coating floating flooring that has 22dB.

 

12Mm Floating 12Mm Underlay Sound Rate Iic Stc
12Mm Floating 1/4″ (6Mm) Underlay Sound Rate Iic Stc

Solution for 6” concrete slab construction building:

  1. 6” concrete slab construction building = 27 dB for the concrete slab)
  2. Add 1/2″ (12mm) cork underlayment = 48dB
  3. Other flooring such as engineer hardwood, Vinyl = (0dB)

Compare products using reports that identify the complete tested assembly. A product-only figure does not predict the final result in every building.

12Mm Floating 12Mm Underlay Sound Rate Iic Stc
1/2″ (12Mm) Floating 1/2″ (12Mm) Underlay Sound Rate Iic Stc

Give the board the relevant test report and a sample of the proposed flooring and underlayment. Ask whether it requires a laboratory rating, a field test, or approval of a specific assembly before installation.

 

We have helped customers prepare cork-flooring documentation for condo review. Check the bylaws first, then match the requested rating and test method to the applicable report.

12Mm Floating 3Mm Underlay Sound Rate
1/2″ (12Mm) Floating 3Mm(1/8″) Underlay Sound Rate

When it comes to sound insulation, cork ranks #2 in the world.  It is second only to SOLID RUBBER.  Solid rubber is not to be confused with “foam rubber” which is what is what most underlay on the market is made from.  Foam rubber is nothing better than a thick plastic bag.  Cork and cork underlayment have some of the best numbers (sound rating and thermal insulation) in the industry.  Our 12mm (1/2 inch) cork underlayment ($1.49/sf) is worth the same as 8mm (5/8 inch) of solid rubber underlayment ($10-$20/sf).  As thermal insulation, it is equal to 2 inches of solid Styrofoam insulation (the stuff on the outside of a house to keep it warm = $4-$8/sf). 

 

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