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Winter Insulation And Black Spot Mould Prevention?

When the temperatures drop, most people reach straight for the thermostat. The problem? Turning the heating up doesn’t fix cold walls, condensation or black mould, it just burns more gas and money. That’s where TIWI CorkPlaster comes in.

At TIWI CorkSpray, we use a new generation of cork-based plaster systems that create a thin, breathable, insulating layer on your walls. It’s designed to make your home feel warmer and drier this winter, without losing space to bulky internal wall insulation.

In this post, we’ll walk through what cork plaster is, how it works, and why it’s a game changer for cold, damp UK homes.

What Is Cork Plaster?

TIWI Cork Plaster is a thin, trowel-applied coating made from natural cork granules and specialist binders. It’s applied directly to your existing walls to create a seamless, breathable, insulating finish.

Unlike traditional internal wall insulation boards, cork plaster is:

  • Thin – typically just a few millimetres

  • Natural – made from cork, a renewable, carbon-negative material

  • Breathable – helps moisture escape instead of trapping it in the wall

  • Versatile – suitable for internal walls and, in some systems, ceilings and problem areas

You get the benefits of insulation and moisture control, without losing precious room space or moving radiators and sockets in most cases.

Why Winter Is The Perfect Time To Think About Cork Plaster

Winter is when the real problems show up:

  • Cold external walls

  • Condensation on corners and around windows

  • Black mould behind furniture, beds and wardrobes

  • Rooms that never feel properly warm, no matter how long the heating is on

Cork plaster helps tackle the cause of these issues, not just the symptoms.

By adding a thin, insulating, airtight layer to the inside of your walls, you:

  • Reduce cold spots where condensation loves to form

  • Make surfaces feel warmer to the touch, improving comfort

  • Help control mould growth by managing moisture and surface temperature

  • Improve acoustic comfort, softening echo and reducing noise slightly

You still need sensible ventilation, but cork plaster gives your walls a huge advantage in the fight against winter damp and discomfort.

Key Benefits Of Cork Plaster For Cold, Damp Homes..

1. Warmer-Feeling Walls Without Losing Space

Traditional internal wall insulation can be 50–100mm thick. That means:

  • Moving radiators

  • Adjusting skirting boards and sockets

  • Losing noticeable floor space

Cork is applied in thin layers, giving you a meaningful improvement in comfort and surface temperature without major disruption. It’s ideal for:

  • Solid brick or stone walls

  • Cold gable ends

  • North-facing rooms

  • Problem patches where mould keeps returning

2. Helps Reduce Condensation And Mould

Mould loves cold, damp surfaces. Cork is naturally:

  • Breathable – allows moisture vapour to pass through the wall

  • Resistant to mould and rot – cork doesn’t provide a food source for mould

  • Thermal – it helps keep the internal surface of the wall warmer

This combination makes it much harder for condensation to sit on the surface and feed mould growth. For many homeowners, that means:

  • Less mould behind furniture

  • Fewer black spots in corners and around windows

  • A healthier, more comfortable living environment

3. Natural, Eco-Friendly And Carbon-Negative

Cork is harvested from the bark of cork oak trees without cutting the tree down. The bark regrows, and the tree continues to absorb CO₂.

That means cork-based products are:

  • Renewable

  • Low impact compared to many synthetic materials

  • Carbon-negative over their lifecycle

If you care about comfort and the environment, cork plaster is a powerful way to improve your home without relying on petrochemical-based materials.

4. A Durable, Attractive Finish

Cork plaster isn’t just a “hidden” layer – it can also provide a beautiful final finish.

Depending on the system used, you can achieve:

  • Smooth or lightly textured surfaces

  • A range of colours or a base ready for paint

  • A tough, long-lasting coating that resists cracking and flaking

So you’re not just solving a technical problem; you’re upgrading the look and feel of your space at the same time.

Where Cork Plaster Works Best In Winter

We’ve found our very own cork-based internal solutions particularly effective in:

  • Bedrooms with external walls that feel cold and attract mould

  • Living rooms where you sit next to a cold wall and feel a constant draught

  • Behind wardrobes, beds and sofas where air circulation is poor

  • Bay windows and alcoves that are prone to condensation

  • Older solid-wall properties with no cavity to insulate

Because the system is thin and flexible, it’s ideal for awkward shapes, reveals and details where traditional boards struggle.

What To Expect From A Cork Plaster Installation

Every property is different, but a typical internal cork plaster project usually follows these steps:

  1. Survey & Advice We assess the walls, existing issues (condensation, mould, flaking paint), and talk through your goals for comfort and appearance.

  2. Preparation

    Any loose material is removed, surfaces are cleaned, and mould is treated where necessary. We make sure the substrate is sound and ready.

  3. Application Of Cork Plaster System

    The cork plaster is applied in thin layers by trained installers to create a continuous, seamless coating.

  4. Finishing

    Once cured, the surface can be left as-is (depending on the system) or finished to your chosen look – for example, a smooth finish ready for paint.

  5. Enjoy A Warmer, Healthier Room

    You’ll notice the difference most on cold days: walls feel warmer, rooms are more comfortable, and those stubborn problem areas are finally under control.

Is Cork Plaster Right For Your Home This Winter?

Cork plaster is not a magic wand, and we never make wild claims about exact energy savings. What we can say from experience is:

  • Rooms feel more comfortable at lower thermostat settings

  • Cold, damp corners become far less of a problem

  • Many customers see a noticeable reduction in mould growth when combined with sensible ventilation

If you live in a solid-wall property, struggle with condensation and mould, or simply want a more natural, space-saving way to improve comfort, cork plaster is well worth considering before another winter passes.

Ready To Talk About Cork Plaster For Your Home?

If you’d like tailored advice on whether cork-based internal solutions are suitable for your property this winter, we’re happy to help.


We’ll look at your specific walls, your winter challenges, and recommend the most effective, realistic solution – no pressure, no hype, just honest guidance.


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