Brick and clinker

What is the difference between clinker and ordinary brick?
Bricks are made of clay and loam, with or without slimming admixtures, and then burns out. A distinction is made between the facing brick and the brick used on the inside. Only the facing brick used from the outside is not plastered and should be frost-resistant. Clinker is a type of brick that is fired at high temperature, causing sintering (melting of raw materials). Clinker is basically a frost-resistant brick. Its surface is more airtight than that of ordinary brick, therefore, it is more resistant to acid substances.

What efflorescence are formed on clinker cladding?
Sulfates may be present in the facing clinker, nitrates (salt), carbonates and vanadium salts, manifesting in the form of eruptions. Vanadium efflorescence is due to insufficient sintering, that is why they appear in a clear veneer, pastel colors; they are green in color.

Old, an unplastered clinker wall is to be impregnated. What characteristics of the substrate should be examined?
Check the moisture of the foundation, the presence of eruptions, brick falling off, scratch, Dirty, the presence of mosses, lichen and fungus.