Patching & Priming products
Priming products for plasters and renders perform the same function as priming for paint. They are even more critical to use under renders because any differences in the substrate porosity will show through a plaster or render as differences in colour or texture, or lines and cracks.
Patching products are used on joins so that any movement is contained within the wall and doesnt show through the render as cracks.
Priming paints are applied so that the surface has even absorption. On thin decorative lime plasters two coats of primer will often be applied to make sure the substrate porosity is totally even so the final coat is even.
Priming paints for plasters and renders usually contain a fine grit to help with adhesion.