When installing an External Wall Insulation (EWI) system or applying certain render systems, reinforcing mesh is an important part of the build-up. It is used within the reinforced basecoat layer before the final render finish is applied.
For anyone planning an EWI or external render project, understanding what reinforcing mesh does, where it is used and how it works with other materials can help when selecting the right system components.
At Infinity PM, we supply fibreglass reinforcing mesh alongside EWI basecoats, insulation boards, fixings, profiles, primers and render products for trade projects.
What Is Reinforcing Mesh?
Reinforcing mesh is a mesh material, commonly made from glass fibre, that is embedded into the basecoat or adhesive layer of an EWI system.
Its role is to reinforce this layer and provide a stable base for the finishing render. ATLAS describes its reinforcing mesh as an alkali-resistant, durable and flexible component used within thermal insulation systems with materials such as polystyrene and mineral wool.
The mesh is not normally the visible final layer. Instead, it sits within the reinforced coat, with the basecoat covering the mesh before the finishing render is applied.
Why Is Reinforcing Mesh Used in EWI Systems?
An EWI system is made up of several layers, and each component has a specific purpose. A typical system can include insulation boards, adhesive, mechanical fixings, a reinforced basecoat layer, reinforcing mesh, primer and a final render finish.
The reinforcing mesh helps the basecoat layer deal with stresses and movement within the external insulation system. Its flexibility can help accommodate thermal and mechanical deformation and contribute to reducing the risk of cracking within the façade layers.
This is why reinforcing mesh should be considered as part of the overall EWI system rather than as an optional decorative material.
How Does Reinforcing Mesh Work With Basecoat?
The reinforcing mesh is embedded into the basecoat while the material is being applied.
The basecoat is spread over the insulation surface and the mesh is incorporated into the adhesive layer. It should be properly embedded and covered rather than left exposed at the surface.
ATLAS installation guidance describes the reinforced coat as a layer of adhesive containing glass fibre mesh. The guidance also specifies that the mesh should be fully embedded in the adhesive and that adjacent mesh strips should overlap.
The exact installation method, materials and requirements can vary depending on the EWI system being used, so the relevant manufacturer's technical documentation should always be followed.
Reinforcing Mesh and Render Systems
Reinforcing mesh is not limited to one particular insulation material. It can form part of EWI systems using different insulation types, including EPS and mineral wool, when specified as part of the relevant system.
The mesh works together with the basecoat to create a suitable surface for the final render.
This means the choice of mesh should not be made separately from the other components. The mesh, basecoat, insulation and render should be compatible with the intended system.
Why Correct Installation Matters
The performance of a reinforced render or EWI system depends on the complete build-up and correct installation of its individual components.
Poor application of the reinforced layer can contribute to problems such as cracking or detachment. ATLAS guidance highlights the importance of sufficient basecoat coverage and correct reinforcement around areas such as window and door openings.
Particular attention may also be required around corners, openings and other areas where additional reinforcement is specified.
For example, ATLAS guidance describes additional diagonal mesh reinforcement around window and door corners to help address areas where stresses can accumulate.
Reinforcing Mesh Over EPS and Mineral Wool
Reinforcing mesh can be used with different insulation systems, but the exact products and installation details depend on the system specification.
For example, ATLAS documentation identifies glass fibre reinforcing mesh as a component within systems using both EPS and mineral wool insulation.
This is another reason why it is important to select compatible system components rather than treating individual EWI products as interchangeable.
Reinforcing Mesh vs Mesh-Integrated Profiles
It is also worth understanding the difference between standard reinforcing mesh and profiles that already include mesh.
A standard reinforcing mesh is used across the main reinforced basecoat layer.
Profiles such as corner beads and stop beads can include an integrated mesh wing. These are designed for specific areas such as external corners and edges, helping reinforce those details while also providing a defined finish.
Both can form part of a complete EWI or render system, but they perform different roles.
What Should You Consider When Choosing Reinforcing Mesh?
Before purchasing reinforcing mesh for an EWI or render project, consider:
- The insulation system being installed
- Whether EPS, mineral wool or another system is being used
- The compatible basecoat or adhesive
- The specified mesh type
- The manufacturer's installation requirements
- Areas requiring additional reinforcement
- Required overlaps and detailing
- Compatibility with the final render system
For a complete EWI build-up, it is important to consider all components together rather than selecting the mesh in isolation.
Reinforcing Mesh for EWI Projects from Infinity PM
Infinity PM supplies fibreglass reinforcing mesh alongside a range of EWI and render materials, including EPS insulation boards, basecoats, insulation fixings, profiles, primers and finishing renders. The current range includes ATLAS products and other materials for professional EWI and external render projects.
If you are planning an EWI or render project, choosing compatible materials is an important part of creating the correct system build-up.
Explore reinforcing mesh and EWI materials at Infinity PM for your next project.