Render mesh or mesh cloth is used for wall reinforcement plastering, rendering, roof waterproofing and external wall insulation. This innovative intricately woven fibreglass mesh is a key part of modern rendering; long gone are the days of using chicken wire or stainless steel mess. Embedding mesh in your render system will reinforce your render, help resist wear and tear, strengthen and prevent against cracking and generally ensure your render stands the test of time.
Render mesh is designed with strength and flexibility in mind, working in harmony with modern flexible and breathable renders. With changes in weather and temperature, external walls can expand and contract minutely however mesh enables your render system to flex and prevent cracking with these small movements. Render Mesh is also ideal for holding insulation boards together in EWI systems.
When selecting your mesh look for a quality product with a pressed weave, if not the mesh can fall apart and can compromise the structural integrity of your render system. Also ensure the mesh is alkaline resistant, without this quality the chemicals in the render will break down the mesh and cause weakness in your finished render. You can purchase various weights depending on where the product is being used. Heavier meshes are ideal for more impact resistance such as sports walls/surfaces than can take a beating from balls or pounding feet. It will also given you peace of mind that render mesh is designed with fire resistant properties to give your property extra protection.
Some contractors will fully mesh their render for additional reinforcement whilst others will apply at stress points and openings. Stress points include above and below openings such as windows and doors as well as at junctions of dissimilar materials and crack inducers like weep holes. Corners are also well known to be weaker areas however combining mesh with beads will ensure you achieve a strong finished result. As with any building material or product, always refer to the spec sheets provided to ensure the product is suitable for the render.
The positioning of mesh within your render is vital. It shouldn't have contact with the substrate and should avoid being exposed by the scraping process. The mesh should be placed within the first 5-10mm of the total render coat. You should press evenly into a freshly applied pass of basecoat using a trowel or spatula. It must be embedded in wet on wet process to achieve the necessary bond and should never be mechanically fixed. You should also always overlap the mesh (at least a 50mm overlap) to prevent gaps where cracks can occur.