To better understand why we distinguish some plasters as veneers it may be helpful to review how plasters have been applied traditionally. A traditional plaster render is typically a two or three coat application that has a total thickness of at least 5/8-inch, often even thicker. These are generally applied to two kinds of substrates. Plaster renders can be directly applied to some kind of masonry unit such as stone, brick, terracotta, rammed earth and adobe or industrially produced materials such as CMUs (cement masonry units), AAC block (autoclaved aerated concrete) or cast-in-place concrete panels to name a few. The other traditional means of applying plaster is over a lath substrate mechanically affixed to a timber support.
Lath is a type of net or web that the plaster is pushed through, hangs on to and sets around. Lath supports can be made of traditional reeds (wattle) and wood strips, as well as by industrial processes such as expanded metal and plastic laths.