Internal Wall Insulation

Diathonite internal wall insulation (IWI) is a lime-based insulated render that makes properties more energy efficient without impacting the breathability of the underlying surface. As the insulation is installed internally, it does not change the external appearance of the building. Diasen Diathonite Evolution is an excellent option for commercial projects or Listed Buildings. Architects and project managers who are looking for specialist, high-performance insulation can rely on our team to meticulously meet their specifications.

What is solid wall insulation?

Heat transfers faster through solid material than across a cavity. Because of thermal bridging, homes with solid walls often require additional insulation in order to improve their heat retention and increase their energy efficiency. Solid wall insulation refers to a category of products, including external wall insulation, that have been developed to meet these requirements.

Quality products, sustainable focus

As part of our commitment to sustainability, we source our internal wall insulation from Ecological Building Systems.  As approved installers, we are proud to work with high-quality, innovative products from manufacturers like Diasen that allow us to improve the quality of the built environment.

When it comes to enhancing the energy efficiency of the buildings we work on, these products allow us to transform thermal performance whilst also meeting conservation requirements. Internal wall insulation is the best way to eliminate thermal bridging within solid stone or masonry walls.

The benefits of internal wall insulation

We use Diasen Diathonite Evolution to add an attractive, breathable plaster layer to internal walls. We are approved installers for this system and have received training from Diasen to ensure that we achieve the best possible results. This lime-based plaster system has several key benefits:

  • Thermal performance

    A 50mm layer of plaster will improve the thermal performance of a wall by 3.5 times. This can be increased to 4.5 times with a 75mm layer.

  • Breathability

    Moisture is drawn out of the structure of the building through capillary action, helping it to dry out and avoiding humidity, condensation, or mould.

  • Versatility

    This plaster is suitable for hand or spray application in 15mm layers, providing a range of options for any project and ensuring swift, straightforward installation.

  • Fast drying

    The drying time for Diathonite Evolution is much faster than traditional lime plasters. You can expect it to take around 1/3 or the time (approximately 2mm per day).

  • Fire resistance

    Diathonite Evolution has class A1 fire resistance, meaning that it will not generate flames or emit smoke. It is certified according to UNI EN ISO 13501-1.

  • Natural

    Made from natural ingredients such as hydrated lime, clay, cork, and diatomaceous earth, the system is environmentally friendly and exhibits great elasticity.

A greener choice for your property

Adding insulation to a property is the ideal way to retain heat and reduce the amount of energy that is needed to heat it effectively. Solid wall insulation is a particularly important investment as it improves the performance of the properties that are impacted the most by heat loss. Adding this additional layer helps to prevent unwanted heat transfer, ensuring that the property is prepared for the impact of climate change. The UK has a 2028 target for effectively insulating all commercial buildings – solutions like Diathonite will be key to achieving the desired energy performance.

Perfect for Historic and Listed Buildings

Diasen Diathonite Evolution is ideally suited for restoration projects, helping to control moisture within solid stone or masonry walls. Here’s why:

  • The all-natural ingredients that are used meet conservation requirements
  • Using this system contributes to Leadership in Energy and Environmental Design (LEED) credits
  • The plaster’s alkalinity helps to prevent mould and condensation
  • It can be used to level and insulate walls without impacting their character
  • The plaster’s elasticity leads to durable results, avoiding future work and disruption

Additional installation options

Where energy performance is particularly essential, Diathonite Evolution can be applied beneath Gutex boards. This approach adds significant additional insulation to the space in question and maximises the efficiency of the system. As Gutex is also a sustainable product, being manufactured from recycled wood chips, its use ensures that the project’s environmental impact remains minimal. We work closely with architects and project managers to create suitable, sustainable solutions for their project requirements.

Commercial installations

We work on commercial projects too, partnering with builders and architects to ensure that their properties are insulated effectively. No matter the scale or complexity of the project, we’ll be able to meet every requirement.

Commercial IWI installation

Solid wall insulation in action: St Lawrence’s Church, Brentford

This Grade II* listed building has been empty since the 1960s and was added to the Heritage at Risk list. However, it is now in the process of being redeveloped into leisure facilities for the local community.

With the body of the church dating back to 1764, the church tower to the 15th century, and many of its renovations to the 19th century, it’s no wonder that the building’s energy efficiency didn’t meet modern standards. The church ceiling was insulated and coated with a spray application of Diasen Diathonite Evolution. A topcoat was then applied to create the desired finish.

Using IWI in this project ensured that the work complied with conservation requirements, provided the necessary thermal performance, and minimised any environmental impact.







See some of our previous projects in our gallery.

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Contact AMJ Contracts

We are here to offer help and advice. If you want to arrange for your free, no obligation quote, call 020 3633 1074 or email .