Short answer: cork underlay is made of agglomerated cork granules; rubber cork underlay combines cork granules with rubber for a denser, more resilient layer. CorkMart supplies cork underlay in 1 × 10 m rolls (10 m²) from 2 to 8 mm, and rubber cork underlay in 1 m wide rolls of 5, 10 or 25 m from 1.5 to 7 mm. Choose by what your floor manufacturer allows first, then by feel, room use and budget.
Cork underlay and rubber cork underlay compared
| Cork underlay | Rubber cork underlay | |
|---|---|---|
| Composition | Agglomerated cork granules | Cork granules combined with rubber |
| Thicknesses at CorkMart | 2, 3, 4, 5, 6 and 8 mm | 1.5, 2, 3, 4, 5, 6 and 7 mm |
| Roll format | 1 m × 10 m | 1 m × 5 m, 10 m or 25 m |
| Coverage per roll | 10 m² | 5, 10 or 25 m² |
| Character | Lighter, natural cork feel | Denser and more resilient |
| Typical choice | Natural material projects and floating floors that accept cork | Busier rooms and floor systems that call for a denser layer |
What is cork underlay?
Cork underlay is a thin layer of agglomerated cork placed between the subfloor and the finished floor. It provides a natural, resilient base and is commonly used under floating floors such as laminate and engineered wood, where the floor manufacturer permits a cork underlay.
What is rubber cork underlay?
Rubber cork underlay mixes cork granules with rubber. The result is denser and more elastic than cork alone, which is why it is often chosen where a more robust layer is needed or where the floor system specifies this type of material.
How to choose
- Floor manufacturer first: many floating floors set a maximum underlay thickness and minimum compressive strength. Thicker is not automatically better.
- Floor type: the floor system decides whether cork, rubber cork or another layer is allowed.
- Room use: busier rooms and commercial areas often justify the denser rubber cork option.
- Moisture: neither underlay replaces a moisture barrier unless the floor-system specification says so.
- Acoustic goals: both are used in impact sound build-ups, but the result depends on the complete floor system. No acoustic value should be assumed from the underlay alone.
How many rolls do you need?
Measure the room, add 5–10% for cuts, and divide by the coverage of one roll. Round up to full rolls.
Example: a room of 18 m² plus 5% needs about 18.9 m². In cork underlay, that is 2 rolls of 10 m². In rubber cork underlay, you can choose two 10 m rolls (20 m²) or one 25 m roll (25 m²) if you want spare material for another room.
Installation basics
- Prepare a clean, dry, level and sound subfloor.
- Lay the strips edge to edge without overlapping, and tape the joints if the floor system requires it.
- Follow the finished-floor manufacturer’s instructions for direction of laying, expansion gaps and any required barrier layers.
Frequently asked questions
Which underlay thickness should I use under laminate?
Use the thickness allowed by the laminate manufacturer. Floating floors often specify thin underlays, so check the maximum before ordering.
Does cork underlay replace a moisture barrier?
No, not unless the floor-system specification explicitly says so.
How many rolls do I need for 20 m²?
With a 5–10% allowance you need 21–22 m²: 3 rolls of cork underlay (10 m² each), or one 25 m roll of rubber cork underlay.
Is rubber cork better for sound?
Both are used in impact sound systems. The actual result depends on the complete floor build-up, so follow the floor system’s tested specification.
Browse Natural Cork Flooring Underlay, Rubber Cork Flooring Underlay or the Cork Flooring & Underlay collection. For larger projects, send your area and floor type through Request a Quote.
