Coverage will depend on the skill of the applicator, the density of cover required and wastage during application. As a guide application rates in the order of of 3kg per sqm may be expected. ie a 15kg pack could be expected to cover approximately 5sqm.
Description & Application:
UK Sourced natural cleaned, crushed and whole cockle shell offered as a substitute for Barra Shell Harling. This product represents the best material available for the repair and creation of renders cast with Barra Shell.
Depending on the specific application some of the larger whole pieces of cockle may require to be broken down using a lump hammer or similar prior to application.
The original weather bleached white Barra Shell was collected from the island of the same name in the Outer Hebrides. The shell beaches on the Isle of Barra are part of a complex series of raised beaches found on the Highland and Island coasts of West Scotland. The most recent beaches were formed around 12,000 years ago when the melting of ice sheets in Northern Europe caused a rapid increase in sea level which pushed the beaches inland. However, the removal of the mass of ice also caused the land to slowly rise (a process known to geologists as isostacy) leaving these ancient beaches as we see them today, quite literally high and dry.
Harling is a Scottish term describing the technique of providing a decorative waterproof render. The technique has also been adopted in other parts of the UK where it is known as Pebble or Dry Dashing.
Based traditionally on lime, but more recently cement mortars have been used to provide a provide a base course. Stone chippings, pebbles, crushed and whole shells are then broadcast onto the surface and lightly pressed in to provide a durable and decorative finish.
The technique has been used on buildings from modest sea-side cottages to famous buildings including the Great Hall in Stirling Castle
Barra shell harling from Specialist Aggregates.