Managing damp and mould in buildings, particularly those with solid stone or brick walls, is a common challenge in both historic and modern properties. Traditional gypsum plasters have the tendency to retain moisture and are pH neutral, which can worsen problems such as condensation and mould growth. This, in turn, may result in diminished air quality, damaged surface finishes and possible health concerns. Diasen Diathonite provides a natural solution that effectively manages moisture while fostering a comfortable indoor environment.
Diasen Diathonite is an exceptionally breathable, cork and lime-based thermal plaster that facilitates the natural movement of moisture through walls, enabling it to evaporate effectively. With its capillary-active properties, it efficiently helps control humidity levels and allows moisture to dry out if unforeseen moisture issues occur. Unlike conventional cement plasters, Diathonite doesn’t trap moisture, reducing the risk of mould and damp spots. Any pre-existing leaks or sources of moisture ingress must be remedied before installation begins.
The thermal insulation provided by Diathonite further helps reduce condensation by raising the temperature of the interior surface of the wall. Even a thin layer of Diathonite can raise the surface temperature adequately, reducing the risk of prolonged high humidity, which also helps reduce the occurrence of condensation on internal surfaces.
When applied to internal walls, Diathonite helps to minimise condensation, promoting a healthier and more comfortable living environment. It encourages the movement of moisture away from the building, helping to prevent long-term damage and deterioration of the fabric.
This system is highly effective for buildings with high moisture levels, or for areas like basements, bathrooms, and kitchens, where dampness is common. Its natural composition ensures a healthy environment, free of harmful chemicals, whilst promoting improved air quality.
About Diasen Diathonite
Diasen Diathonite is designed to effectively manage damp and mould in both residential and commercial buildings. By combining natural lime with innovative moisture-regulating properties, the plaster allows moisture to move naturally through walls, which helps prevent condensation and reduces the likelihood of mould growth. It also insulates the wall, helping to prevent water from condensing onto cold surfaces, while providing a durable and breathable finish that lasts.
Applied to internal walls, Diathonite’s natural ability to absorb and release moisture helps maintain balance without holding onto water. Diathonite offers excellent thermal properties that improve energy efficiency and create a comfortable indoor environment while managing moisture levels effectively. By raising the temperature of the surface, it helps reduce condensation, and its lime-based formula gives it a high pH, helping create an inhospitable environment for mould. This makes it an ideal choice for spaces with high humidity, such as bathrooms, kitchens, and cellars.
As with any Internal Wall Insulation system, the wall must have any sources of water infiltration from ground sources, poor pointing, water leaks or poorly maintained gutters/pipes etc made good before installing the insulation. Refer to our guidance document: “How to prepare walls for Internal Wall Insulation” for full details.
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This system guide details the key system components and performance information for the Diasen product range.
Diasen Diathonite effectively manages damp and mould by promoting breathability and regulating moisture levels. Its lime-based, capillary-active composition allows walls to breathe, preventing water accumulation and minimising condensation. Diathonite is perfect for areas with high humidity, as it helps minimise the chances of mould and damp spots, promoting healthier living conditions. As a natural, eco-friendly plaster, it provides a chemical-free option for moisture control and enhances indoor air quality. It offers long-term protection against moisture damage, making it appropriate for both traditional and modern buildings.
Key Benefits
Breathable Lime Plaster
Promotes moisture regulation and prevents moisture buildup.
Prevents Mould Growth
Alkaline lime-based formula inhibits mould growth.
Ideal for High-Humidity Areas
Perfect for kitchens, bathrooms, and basements.
Improves Indoor Air Quality
Prevents condensation and water-related issues that lead to mould.
Natural, Eco-Friendly Composition
No harmful chemicals or synthetic additives.
Long-Term Protection
Guards against moisture damage, preserving building integrity.
Diasen Thermactive.037 Lime and cork based insulating plaster
Diasen Argatherm Breathable lime-based finishing plaster for a smooth to semi-smooth finish
Auro Natural Breathable Paint
For walls that have been exposed to dampness in the past, Deumix Plus in combination with Thermactive (or Evolution) offer a great solution. Deumix Plus is specifically designed to help the wall dry out safely while minimizing salt deposits. It contains a built-in salt inhibitor and is highly capillary active, making it perfect for walls that have had sources of dampness fixed but are still drying out.
Thermactive, a high-performance thermal insulation material, helps reduce heat loss through walls, stabilise indoor temperatures, and improve overall energy efficiency. For areas facing significant moisture issues, Evolution can provide additional moisture management properties, enhancing thermal comfort and contributing to long-term durability.
- Diasen Thermactive.037 lime and cork based insulating plaster
- Diasen Argatherm breathable lime-based finishing plaster for a smooth to semi-smooth finish
- Auro Natural Breathable Paint
For walls that have been exposed to dampness in the past (which have now been resolved) and are now experiencing serious salt issues such as efflorescence (the white, powdery salt deposits that occur on damp walls), require a specific solution. The combination of Regularisation and Thermactive offers an effective solution. Regularisation contains an extra strong salt inhibitor, specifically designed to handle the most severe salt issues. It is ideal for walls with significant salt contamination and provides even more salt resistance than Deumix Plus. The addition of Thermactive on top of Regularisation provides the thermal benefit required for the wall.
Thermactive, a high-performance thermal insulation material, offers excellent thermal resistance, helping to insulate walls, reduces moisture buildup, and prevents further damage. This system helps stabilise the indoor temperature, reducing energy consumption and maintaining a consistent climate inside the building.
Walls which are below ground level with no existing tanking system installed internally or externally, are very prone to moisture penetration. In such cases it is essential to prevent moisture ingress prior to installing Diathonite. This is achieved by use of Diasen Watstop, an epoxy cement-based waterproof tanking plaster installed onto the interior of the masonry wall. To maximise coverage and achieve a consistent application, it is recommended to level the wall with Diasen Regularisation restoration plaster before applying the Watstop.
Watstop is applied 50cm above the damp area, for example if the exterior ground level is at 50cm above the finished floor and the damp area extends to 1m, Watstop should be applied up to 1.5m.
If the wall is seeping water or the moisture content is greater than 4%, Watstop is not suitable. Please contact our technical team for advice.
Typical U-values of a Brick or Stone Wall (W/m²K)
Wall Type | Thickness of Application (mm) | Diathonite Evolution U-Value (W/m²K) | Diathonite Thermactive U-Value (W/m²K) |
|---|---|---|---|
| 220mm brick | Uninsulated wall* | 2.19 | 2.19 |
20 | 1.07 | 0.97 | |
30 | 0.86 | 0.77 | |
40 | 0.72 | 0.63 | |
50 | 0.62 | 0.54 | |
60 | 0.55 | 0.47 | |
70 | 0.49 | 0.42 | |
80 | 0.44 | 0.37 | |
90 | 0.40 | 0.34 | |
100 | 0.36 | 0.31 | |
110 | 0.34 | 0.28 | |
120 | 0.31 | 0.26 |
Wall Type | Thickness of Application (mm) | Diathonite Evolution U-Value (W/m²K) | Diathonite Thermactive U-Value (W/m²K) |
|---|---|---|---|
| 500mm stone | Uninsulated wall* | 2.38 | 2.38 |
20 | 1.11 | 1.00 | |
30 | 0.89 | 0.79 | |
40 | 0.74 | 0.65 | |
50 | 0.64 | 0.55 | |
60 | 0.56 | 0.48 | |
70 | 0.49 | 0.42 | |
80 | 0.44 | 0.38 | |
90 | 0.40 | 0.34 | |
100 | 0.37 | 0.31 | |
110 | 0.34 | 0.29 | |
120 | 0.32 | 0.27 |
* Adopting best practice, the values given for existing uninsulated stone and brick walls are derived from EN ISO 10456: 2007. U-values can vary depending on stone or brick type.
Above based on Argatherm applied at a thickness of 4mm (2 coats of 2mm).
Diasen Diathonite Deumix Plus
Diasen Diathonite Regularisation
