The plaster is often revered for its timeless aesthetic beauty, as well as its durability and resistance. Not only is the ancient application incredibly hard-wearing, it also has low resistance to vapour diffusion, making it breathable and safe for every environment. It also has superior insulating properties due to its high micro-porosity.
Many builders and decorators will wax lyrical about the application’s many qualities – particularly its flame resistance, anti-bacterial properties and highly durability. It is also incredibly flexible and easier to apply than traditional decorating materials. But what actually is Venetian plaster and how is it made?
The process is lengthy and relies on a number of precise variables in order to end up with the perfect make-up. The product is made from lime – an ancient, renewable and highly resistant material that originates from pebbles. These pebbles (which are rich in calcium carbonate) are slowly transformed into a slaked lime product using a carefully orchestrated balance of tradition and technology.
The pebbles are baked in a wood kiln, as they would have been in more primitive times. It’s important to interject here, as the most environmentally responsible companies won’t chop down trees in order to make their kilns. The best manufacturers will use recycled wood sourced from carpenters and other sources.
Sawdust (usually collected in large amounts of scrap from local tradesmen) is then blown into the oven to burn the pebbles, rather than incorporating harmful chemicals such as gas or petroleum. This also prevents the need for electricity, saving once again on ecological consumption.
The pebbles are baked for over a week in the kiln, with an automatic control system monitoring the temperature and process. An innovative filtering system is then used to dampen the emissions into the atmosphere, making the process safer, and more environmentally friendly, still.
At this stage, the pebbles have usually crumbled into a quicklime substance. They are then immerged in water, where they will dissolve into liquid form, ready for the next stage of the process.
The substance is filtered once again in order to remove any unbaked lime that could potentially jeopardise the quality of the product. The slaked lime is then poured into a maturation tank, where it rests for approximately six months. This is typically the minimum time needed for it to mature into a chemical structure – so the process cannot be hurried.
One it has been left to rest, the lime is chemically balanced to make sure it is of the best possible quality and meets all safety requirements. Before it enters the manufacturing process, it is micro-filtered again to ensure the removal of even the smallest impurities, and create the creamy texture we now recognise as plaster.
If you’re looking to source Venetian plaster for your decorating project, it’s important that you use a good-quality, environmentally responsible supplier. If in doubt, it’s best to consult the company about how the product has been made. You can also look for customer reviews online to inform you of the quality of their materials.