Cork Insulation – The Comprehensive Guide

By Jamie Orr
Date 14/09/2022
cork insulation – the comprehensive guide

Photo credit: Rezabond Surfacing

Cork insulation is a great option for buildings up and down the UK. That said, not everyone is completely familiar with the products and how they work. In this article, we’ll explain everything you need to know about cork insulation – from its origins and the different types to benefits and application.

Humble beginnings

The cork insulation journey starts at the source – cork oak trees which are grown mostly in Mediterranean countries like Portugal and Spain. Cork-rich bark from these trees is stripped away, leaving the tree to regrow over the next decade or so.

The cork material gained from this bark has a unique honeycomb-like structure, with numerous empty cells packed into every inch. This gives cork several natural qualities, which are present in cork insulation.

Cork is then ground down into granules and turned into usable insulation, with three main types…

3 types of cork insulation

Boards, panels or sheets

The most common type of cork insulation comes in the form of boards, panels or sheets. These are created by heating the cork granules using steam, activating suberin – a natural binding agent.

They are then pressed into the desired shape, size and thickness, which can range from thick 50mm panels down to thin sheets with less than 10mm depth.

Cork insulation rolls

Alternatively, you can opt for cork insulation rolls. This product is similar to boards or panels but typically thinner, with a depth of less than 5mm.

Because of its size, it does offer less insulation than boards or panels. However, that also makes it well suited to small structures where space is at a premium. You could add a low level of insulation to the walls and ceiling of a playhouse or garden room, for example.

Cork insulation rolls can also be used as underlay for flooring, offering better insulation than alternative materials.

Sprayed cork insulation

Finally, there’s the most recent innovation using the natural properties of cork. Sprayed cork insulation works by breaking down cork granules and using them in a sprayed solution. In contrast to rolls or boards, it can be applied directly onto surfaces without the need for fixings. It’s also suitable for both internal and external use.

How it’s applied

The application of cork insulation depends on which type you’re using.

Bulky boards

Insulation boards are typically fitted on the inside of walls using an adhesive. Once boards have been secured to the wall, they need to be plastered over to provide a surface ready for decoration – the end result can take quite a bit away from the overall space in a room.

Light-duty roll

Similarly, cork roll is fitted using an adhesive and pressed into place to make sure it’s completely flat and smooth against the wall. Because of its light duty nature, it’s not normally plastered over – instead being left as a unique cork surface.

Convenient, high-performance spray

On the other hand, sprayed cork insulation is spray applied. This is undoubtedly the simplest method of installation, providing a smooth uniform surface without the bulk of insulation panels. After two 2-3mm coats of SprayCork, a 2mm skim of plaster is used to finish the job.

Alternatively, it can be applied outdoors. In this case, the sprayed cork insulation is used like a render. After walls are cleaned and prepared, the coating is sprayed directly on without any need to remove or adjust fixtures.

What are the benefits of cork insulation?

As above, the benefits of cork insulation can depend on your chosen product. Below are some of the universal advantages of cork insulation, along with the specific perks of the sprayed variety…

Thermal insulation

First and foremost is thermal insulation. Cork is naturally insulative, meaning that its granules create a fantastic barrier to stop heating passing through surfaces like walls, floors, and ceilings. As a result, you can expect cork insulation of any type to provide some reduction in heat loss – though some products will be superior to others. In turn, that makes it easier to maintain a comfortable temperature, which could reduce your energy bills.

Sound insulation

Cork insulation isn’t just about heat. It’s also a fantastic way to stop sound coming in or getting out of your space. Whether you want more peace or privacy, cork’s empty-cell structure is great at absorbing sound waves, providing a reduction of around 38dB – again, depending on the product in question.


Cork’s empty-cell structure makes it naturally adhesive to a range of materials. While boards and rolls are already compressed into a finished product, a sprayed solution can be applied to walls without the need for an adhesive – and when it’s on, you can rest assured it will stay on.


The unique composition of cork makes it fantastically flexible, whatever form it comes in. That means it’s ideal for wall insulation, as it won’t be affected by the minor natural movement that occurs with many buildings.


That flexible structure also makes cork insulation impressively durable. Its natural elasticity helps it withstand knocks and bumps better than other materials, while retaining its shape.


Looking specifically at sprayed insulation and cork rolls, space-saving is another advantage. With cork rolls, you can obtain a low level of insulation from a thin layer of material. Even better, SprayCork provides this benefit without any compromise on performance.

Water resistant

All cork insulation is naturally water resistant. If it’s being applied to your external walls, your building will be protected from rainwater that might otherwise damage your brickwork or make its way inside your property.

Fire resistance

Believe it or not, cork is also naturally resistant to fire thanks to its origin in hot climates. The material burns very slowly and doesn’t produce a flame – meaning it slows the spread of fire. We’re happy to say that SprayCork has a Euro-class B safety rating as a result.


On top of everything else, cork insulation is breathable too. This means that it doesn’t trap moisture inside a building or its walls, making it the enemy of damp and mould.

Environmentally friendly

Because no trees are felled when harvesting cork, it’s a completely sustainable product. Even better, cork oak trees absorb more carbon dioxide when regrowing their bark, meaning it actually has a positive impact on the environment.

Get a cork insulation quote

If you want to enjoy all the myriad of benefits above, SprayCork is the perfect solution for your walls. At CorkSol, we provide both exterior wall insulation and insulative internal coatings, so you can get cork insulation that fits your requirements or preferences.

To find out more or arrange a quote, simply get in touch on 01484 442 420.

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