Depending on how you look at it, the difference between the mortar between bricks, polished plaster interiors and elaborate stucco is either non-existent or almost complete.
On the face of it, all three of these construction elements use the same basic composition.
There is a cement, water and an aggregate such as sand that are mixed together in various mixes and with various additives to form the different finishes that are endemic to high-quality plasterwork and stuccowork.
However, whilst all three are compositionally very similar, how they are used is very different, and the difference between mortar and the other two is very obvious, the differences between plaster and stucco can sometimes be easy to see but more difficult to describe.
After all, in Italian, where the word “stucco” comes from, it is used to mean both plaster and what the rest of the world describes as stucco.
Here are some of the primary and most common differences between plaster and stucco, both traditionally and in modern architecture, as well as where the meanings have blurred and shifted depending on the region.
Render vs Stucco
The first point of contention that is often found is in the use of the term stucco. As noted above, stucco is a term used to describe any plasterwork in Italy, but how the term is applied in different parts of the world can be a matter of debate.
For example, in the United States, stucco is used to describe any form of exterior siding and plasterwork, typically using a mixture of Portland cement, lime and water, which can include ornate three-dimensional features and flat siding.
In the United Kingdom, however, the latter is typically described as a “render”, with stucco primarily associated with additional decorative features that are found both inside and outside of a building.
Cement Content
Because plaster is primarily used internally, it tends to contain less cement, as its primary role is to create an internal flat surface that can either have a beautiful decorative finish on its own or be painted and decorated according to the desires of the property owner.
Stucco, by contrast, requires a lot more cement as it is primarily used externally and is therefore at the mercy of weather conditions and external forces.
Application
Plaster is an exceptionally versatile building material that can be installed over many different types of surfaces, including both walls and ceilings. More robust mixes are available for external use as well.
Stucco, by contrast, requires a very specific three-stage application on top of a metal wire lath to ensure it sticks properly.
The first coat is applied to this wire lath to prepare the surface to take the stucco, with a second “brown” coat used to create a thick, smooth layer that forms the shape of the stucco on the building’s exterior.
The final top coat is then applied to provide the distinct texture and finish that stucco is known for, which if applied by a professional creates a distinct, long-lasting and unique appearance that can make a home stand out.
