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Granulated cork insulation

We often shy away from choosing alternatives to traditional insulation, worried that “something might go wrong”. So we stick with the “tried and tested”—even when it no longer does the job—and end up battling with fixes and adjustments later on. With expanded cork granules, there's no need for compromise. It's a loose-fill, natural, high-quality insulation material that actually offers superior performance compared to standard cork—and it excels in places where rigid sheets simply won’t fit.

You’ve probably got a few questions – here are the answers!

WHAT IS EXPANDED CORK?

It’s a sustainable insulation material made from the bark of the cork oak tree—the very same bark used to make wine bottle stoppers. Expanded cork granulate comes in the form of irregular, lightweight granules with a rich dark brown hue.

Expanded cork is produced by heating natural cork to high temperatures without any chemical additives. During this process, a natural resin called suberin is released, which acts as a binder. As natural cork is heated, it darkens to a deep brown and expands in volume, creating a lightweight, “puffed” material. This gives it even better insulating properties than standard cork—it retains heat more effectively and provides superior sound absorption.

WHAT ARE EXPANDED CORK GRANULES USED FOR?

It’s most commonly used in construction—as a natural thermal and acoustic insulator. Since it’s loose-fill, it can be easily poured into spaces where mats or boards simply wouldn’t fit. It’s ideal for:

insulating lofts, floors, walls, as well as hard-to-reach areas and narrow gaps (its loose form makes application simple),
filling internal cavity walls, thermal insulation partitions, and cavity wall systems,
pitched roofs (as loose-fill insulation between rafters),
voids and hollow spaces beneath floors,
filling gaps and levelling out uneven areas in ceilings and subfloors,
dry screed systems,
lightweight floor constructions.

Outside of construction, it also has a range of other uses:

as a substrate in terrariums for exotic animals (it's 100% natural and completely safe),
as a decorative mulch for plants and flowers (a sustainable alternative to pine bark),
on film sets – used to mimic rubble or soil, especially in special effects for explosions or collapses,
in model-making and dioramas – it realistically replicates the appearance of natural dark soil.

IS CORK GRANULATE SAFE?

Yes, it holds an official Polish hygiene certificate issued by the National Institute of Public Health. This confirms that it does not cause allergies, irritation, or any adverse effects. At present, we are the only company in Poland offering cork granulate with this certification.

HOW LONG DOES EXPANDED CORK MAINTAIN ITS PROPERTIES?

Up to 50 years—without any loss of insulating performance. It doesn’t absorb moisture, won’t develop mould, and doesn’t rot.

When you come across narrow gaps or awkward corners, things can get tricky. Some of these spots are genuinely challenging—often, expanding foam is the only option, and even that can fall short. Tight recesses in walls are notoriously difficult to deal with. But with cork granulate, there’s no need for cutting or fiddly adjustments. Just pour it in and spread it evenly—it naturally conforms to the space, filling every nook and cranny with ease.

Some materials need constant checking, repairing, or fixing—and then there are those that simply get the job done. Expanded cork falls firmly into the latter category. You pour it in once, and that’s it—job done. There’s no need to start all over again a few months down the line because something’s gone wrong. Cork isn’t a short-term solution—it’s built to last.

And there’s one more major advantage—its lightness. Most insulation materials are heavy—especially if you're aiming for top-tier insulating performance. Cork granulate is the exception: it’s lightweight. You don’t have to choose between warmth and a safe, lightweight structure. With expanded cork, you get both.

And all of this comes with full respect for nature. Cork is harvested without cutting down the tree—only the bark is removed, and it naturally regenerates over time. Expanded cork granulate is made from this bark without the use of chemicals or emissions, often using energy sourced from biomass. Cork oak trees themselves are incredibly valuable—they absorb several times more CO₂ than most other trees, making them a true ally in the fight against climate change.