EWI-744 Insulating Lime Render is part of the EWI Pro Heritage Range, designed for projects where thermal improvement, breathability and moisture management all matter. Formulated with NHL 2 binder, lightweight insulating aggregate and reinforcing fibres, it helps improve the thermal performance of solid wall construction without trapping moisture within the building fabric. Its lightweight structure also improves buildability and allows thicker applications than many traditional lime renders, making it especially useful on older buildings and breathable solid wall build-ups.

Designed for use on suitable internal and external backgrounds, EWI-744 is particularly well suited to traditional masonry, solid wall construction and natural building materials where moisture needs to move through the wall naturally. It can be used internally as a backing coat or brought through to a finish coat before receiving a suitable fine plaster, while externally it is used as a backing coat within a breathable render build-up.

Intended Uses

EWI-744 Insulating Lime Render is suitable for both internal and external applications, making it a versatile solution for a wide range of projects, including:

• Solid masonry and traditional wall construction
• Older properties where breathability and moisture movement are important
• Internal walls requiring thermal improvement and a breathable backing coat
• External breathable render build-ups
• Natural building materials such as hemp, straw and rammed earth
• Suitable render carrier boards and host surfaces with suction
• Projects where insulation and vapour permeability are both required

It is especially appropriate where heat loss needs to be reduced without sealing moisture into the wall, and where a more compatible alternative to dense modern materials is required.

Key Benefits

• Helps improve the thermal performance of solid wall construction
• Highly breathable, supporting natural moisture movement through the wall
• Well suited to traditional masonry and natural building materials
• Lightweight structure helps improve buildability
• Allows thicker application depths than many traditional lime renders
• Suitable for both internal and external use
• Can be used within breathable heritage and refurbishment build-ups
• Contains no Portland cement
• Class A1 reaction to fire

Compatible Products

EWI-746F Fine Finish Lime Render NHL 2
Where a finer external finishing coat is required, EWI-746F can be applied over EWI-744 as part of a breathable lime-based build-up, helping maintain vapour permeability while creating a more refined traditional finish.

Blue Fibreglass Mesh
Blue Fibreglass Mesh can be incorporated where specified within the build-up.

EWI-749 Lime Plaster
For internal applications where a smoother second coat is required, EWI-749 Lime Plaster can be applied over EWI-744 within a breathable lime-based system.

EWI-707 Lime Wash
Lime Wash can be used as a breathable finishing and sealing coat where a traditional decorative finish is required while still allowing moisture to evaporate naturally.

EWI-705 Lime Paint
Once fully cured, Lime Paint can be applied as a breathable decorative finish where colour consistency or a more finished appearance is required, without restricting vapour permeability.

EWI-744 should only be used and finished within breathable lime-based systems to ensure long-term performance, thermal benefit and proper moisture management.

Substrate Preparation

Substrates must be sound, clean and free from contaminants that could impair adhesion, including dust, dirt, mould and loose material. Preparation should suit the condition and suction of the background. Absorbent surfaces should be damped down as needed before application, while dense or low-suction backgrounds may require little or no pre-wetting. Any dubbing out should be completed and allowed to firm up before the main coats are applied. Do not use PVA.

Product Preparation

Mix EWI-744 Insulating Lime Render exclusively with clean water at a rate of 4.5 to 5.5 litres per 9kg bag.

• Add water to a clean container first
• Gradually introduce the powder while mixing
• Mix thoroughly to a firm, workable consistency that holds its shape without slumping
• Allow the mix to stand briefly
• Remix before use

Do not add admixtures or other materials. If part bags are used, the contents should be dry blended first to help maintain consistency, as settlement can occur during storage and transport. Use full bags wherever possible.

Application

EWI-744 Insulating Lime Render should be applied as part of a minimum two-coat system. Coat thickness will depend on the required build-up and method of application. Experienced applicators can typically apply around 30 to 50mm per pass by hand, although lighter passes may be preferred until familiarity with the product is established.

• Apply as part of a minimum two-coat system
• Apply around 30 to 50mm per pass by hand where appropriate
• Scratch each coat to provide a mechanical key before applying the next
• A deeper crosshatch scratch is preferred
• Further coats can usually be applied after 1 to 2 days, depending on site conditions and curing
• The final coat may be finished with a wooden float, or with a sponge float where a more decorative finish is required

Where a decorative lime finish is to follow, apply it while suction remains manageable.

Technical Data

Storage Conditions

Store in dry conditions, in unopened bags and clear from the ground. Bags must be protected from water and damp at all times, and any opened or part-used bags should be resealed. For best performance, use within 6 months of manufacture.

Packaging note:

Please note: this product may be supplied in unbranded packaging.