EWI-748 Lime Basecoat

Product Overview

EWI-748 Lime Basecoat NHL 5 is a breathable lime-based adhesive and reinforced basecoat designed for use within mineral wool and wood fibre external wall insulation systems. Formulated with natural hydraulic lime (NHL 5) and natural pozzolans, it provides strong adhesion, excellent workability and long-term durability.

Its micro-porous structure allows moisture vapour to move freely through the wall, supporting breathable construction and helping buildings regulate moisture naturally.

Intended Uses

EWI-748 Lime Basecoat is used to bond mineral wool and wood fibre insulation boards to substrates and to form the reinforced basecoat layer within breathable EWI systems. The basecoat must be reinforced with alkali-resistant fibreglass mesh to provide structural strength, crack control and impact resistance.

Once cured, it should be finished with breathable coatings such as lime wash or lime paint, or internally with lime plaster where specified.
ECO
FRIENDLY
HIGHLY
BREATHABLE
SEVERE
EXPOSURE
BASECOAT/
ADHESIVE

Data Sheets

Product Data Sheet

Safety Data Sheet

Install Video Guide

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Application Conditions

Substrates must be firm, clean and free from contaminants such as dust, grease, salts, efflorescence or loose material that could impair adhesion. Where necessary, backgrounds should be regularised using a compatible lime mortar before insulation boards are installed. All surfaces should be lightly dampened prior to application to reduce rapid dehydration and support proper curing.

EWI-748 should be mixed with approximately 4.5–5 litres of clean water per 21 kg bag until a smooth, homogeneous mortar is achieved. The mortar is applied to the insulation boards and substrate to ensure full surface adhesion, and once the boards are secured, a reinforcement layer of approximately 6–8 mm is applied with alkali-resistant fibreglass mesh embedded into the fresh basecoat. The mesh must remain fully covered to ensure proper reinforcement and long-term system durability.