Cork Underlayment - 1/8" (3mm) - 150 sq.ft. box

Overview

3mm Cork Underlayment – Density 220 kg/m³ – 300 sq. ft. per carton

Our 3mm cork underlayment is the thinnest option in the Forna collection, designed to enhance comfort, sound control, and thermal efficiency beneath your flooring. When placed underfoot, cork helps reflect body heat, creating a naturally warmer and more pleasant surface to walk on.

Each pre-cut sheet measures 24” x 36” (2 ft x 3 ft). A carton of 50 sheets covers 300 sq. ft. and weighs approximately 46 lbs. Made from 100% agglomerated cork with water-based adhesives. Check the product’s emissions documentation and compatibility with the finished flooring.

Benefits

• Acoustic Performance – Cork’s cellular honeycomb structure (around 40 million cells per cubic cm) makes it highly effective at absorbing airborne and impact noise, outperforming most foam underlays.

• Thermal Comfort – Acts as a natural insulator, reducing heat transfer and helping rooms retain warmth longer.

• Moisture Resistance – Naturally infused with suberin, cork resists mold, mildew, and bacteria growth.

• Elastic Cushioning – Provides a softer step that reduces stress on joints, while adapting to floor movement by expanding and contracting with the surface above.

• Eco-Sustainable Choice – Harvested from the bark of cork oak trees without harming them, cork is a renewable material. Each tree can regenerate for up to 200 years, yielding bark every 9–10 years.

Product Specifications

• Material: 100% Agglomerated Cork

• Thickness: 3mm (approx. 1/8”)

• Sheet Size: 24” x 36” (2 ft x 3 ft)

• Carton Coverage: 300 sq. ft.

• Carton Weight: ~46 lbs

• Origin: Portugal

• Eco Attributes: Formaldehyde-free, recyclable, water-based binders only

• Acoustic Ratings (field tested):

  • IIC 39 on 6” concrete (no suspended ceiling)

  • IIC 53 on 6” concrete (with suspended ceiling)

  • STC 40 on 6” concrete (no suspended ceiling)

  • STC 54 on 6” concrete (with suspended ceiling)

Installation & Applications

• Suitable beneath laminate, cork, bamboo, engineered wood, and solid hardwood flooring

• Works for both floating and glue-down systems

• Compatible with tile and stone installations (with proper methods)

• Improves the efficiency of radiant floor heating systems

Info & Guides

• MSDS
• Resin Statement
• Product Details

HOA approval? Download the HOA Flooring Approval Kit — per-thickness test statements, assembly ratings, certificates, and a cover-letter template your board can file.