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Cornerstone Render System Application Guide

This article is designed to provide a step by step guide for instaling, rendering and decorating the Cornerstone Render System.

Cornerstone New Build and a trowel

For Renovation and New Build Construction using the Cornerstone Render Carrier Board

Cornerstone Render Panels: Cutting, Storing and Use

The panels can be cut with a handsaw or circular saw.

They can be stored externally; however, they must be dry when fixed.

The panels are laid to a close fit, pressed slightly and staggered.

celenit panel staggered

When fixing the panel, a suitable wood screw and washer is needed to avoid damage or stress to the board.

For internal use, it is advisable that the board is left within the room for a few days before application so they can acclimatise to the internal environment.

In the case of false ceilings and facings, ventilation needs to be maintained in order to balance the thermal-hygrometric state of both sides of the panel.

Avoid over heating or excess heat after the panels have been fitted.

Cornerstone Render Panels: Fixing

The surface to which the panel is fixed to must be flat and able to support the load of both the panel and the render.

When fixing the panels, 8 fixings per square meter. This is usually achieved by using 5 fixings per board, 4 corners and 1 in the center.

In the case of plastic fixings, these should penetrate the panel by 50mm.

In the case of metal fixings, these should penetrate the board by 30mm.

The maximum clear span for fixing should be 400mm for the internal 15mm boards and 500mm for the external 25mm boards.

Cornerstone New Build Render: Rendering the Panels

The boards should always be fixed using a brick bond (staggered joint) and fitted flat to the frame. Any cracks must be filled using an appropriate material prior to the render application.

The render must be applied to dry panels.

The render must be applied in temperatures between 50C and 30oC, no lower or higher. This is in order to try and manage any potential issues with cracking.

The render must be protected from low or freezing temperatures, direct sunlight or drying winds.

Each render coat must be allowed appropriate curing time before a further coat is applied.

Cornerstone New Build Render: Render Application

Once the panels have been fitted, the render should be applied as soon as possible.

An initial base coat or bonding coat of Cornerstone New Build CLD35 should be applied to a maximum depth of 8mm.

A layer of Cornerstone 4mm plasterers mesh is to be pressed into this coat when it is fresh.

The mesh is designed to reinforce the base coat of render.

The mesh is generally pressed into this coat using a plasterer’s trowel to ensure that it is embedded sufficiently.

Once the base coat has been applied, it should be left to achieve a full set.

A second coat of Cornerstone New Build CLD35 should be applied to a maximum depth of 7mm.

If the site is reasonably sheltered, this coat can be float finished.

Once this coat has been applied, it should be left to achieve a full set.

In applications where there is higher exposure or a tighter finish is desirable, an additional coat of Cornerstone New Build CLD45 can be applied to a maximum depth of 6mm.

This coat can be float finished.

Once this coat has been applied, it should be left to achieve a full set.

For internal application the top coat of render can be replaced with a lime putty based plaster, such as CLM66, applied to a maximum depth of 3mm.

board mesh text

Cornerstone Render System : Decoration – Beeck Mineral Paint

For longevity and durability, we advise that once the system has been applied and allowed to cure, a decorative finish is to be applied.

We recommend the use of Beeck Mineral Paint for both external and internal decoration.

Beeck Mineral Paints absorb into the render and form a chemical bond through a process known as silicification. This chemical bond achieves a paint finish that is inseparable from the render, resulting in a paint coating that is not subject to flaking or peeling and will offer superior performance, water repellency and unrivaled longevity compared to other paint finishes.

Beeck Mineral Paints are proven in the UK to comfortably last for 10 years and much longer. As they are derived from natural minerals, they are free from chemical additions and have an extremely low VOC content, making them not only a high performance paint, but also an environmentally friendly choice.

beeck text

If you have any questions regarding the Cornerstone Render System and how it could be suited to your application or need any further technical information, please contact the Cornish Lime Company on 01208 79779 or alternatively email –

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2 thoughts on “Cornerstone Render System Application Guide

  1. How does this product work

    1. Hi Sam, thanks for your enquiry. The Render System comprises of different products. What exactly did you want to know? Perhaps give us a call on 01208 79779 and we can talk through your requirements? Many thanks.

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