PermaRock Scratch Render

PermaRock Scratch Render is a pre-mixed render based on cement limestone and specially selected, lightfast and UV stable mineral pigments.


PermaRock Scratch Render is supplied as a dry powder, preblended, ready mixed, cement-lime based exterior through-colour render containing a silicone water repellent agent and requiring only mixing with clean water on site.

This monocouche type render is for single or two coat applications to brick or blockwork masonry and onto surfaces treated with a PermaRock reinforced base coat. The fully cured render is weather resistant and yet provides excellent water vapour permeability, allowing treated walls to ‘breathe’. 

PermaRock Scratch Render can be applied in thick layers which enable the creation of rustication and ashlar effects and is designed to be scraped back using a nail float to achieve a uniformly honed / tooled surface aspect. The water repellent surface reduces water absorption and improves resistance to algae, soiling and frost damage.

Method of Application

Supplied as a dry powder, pre-blended to the specified colour, PermaRock Scratch Render requires only mixing with water on site. The mixed and hydrated material is applied onto the prepared substrate (reinforced base coat) by stainless steel trowel or using plaster projection / spray equipment at a rate of approx. 12-14 mm and levelled using a steel float, rule, or darby. Thicker application, or multiple layer applications, are required if the material is to be tooled to create ashlar effects, etc.

The material is allowed to reach a partial set (typically between 4 and 16 hours, depending on weather and temperature conditions) and is then scraped back to a finished thickness of ca. 10 mm using a nail float.

After completion of the scraping operation, the surface is brushed down with a medium soft brush to remove any loose deposits.

Application / Drying Conditions

Temperature (material, substrate, water and ambient air during application and drying): min. +5 ºC, max +30 ºC. To avoid too rapid drying, the material should not be applied during strong winds or under direct sunlight. Avoid application under high relative humidity conditions or if rainfall or frost / freezing temperatures are likely. “Early” or “Late” scraping should be avoided.

Drying times are dependent on temperature, ventilation and relative humidity. Protection should be provided to newly rendered surfaces to reduce the risk of efflorescence and until the render has fully dried and hardened.


PermaRock Scratch Render is supplied in 25 kg sacks as a dry powder pre-mix, requiring mixing with clean water on site.

PermaRock Scratch Render Base Coat is supplied in 25 kg sacks as a dry powder pre-mix, requiring mixing with clean water on site.

Available Colour / Texture / Grain Size