Sunday, March 17, 2013

Why Plastering Is an Art, Not Just a Skill



Plastering a wall or ceiling may look easy, but anyone who has had a go themselves will know just how tricky it really is. A good plasterer is so highly skilled in his or her craft that they can make the job look effortless. Smooth, creamy plaster glides onto the surface and dries out evenly and perfectly flat – but only when the job is done well.

Most building services companies include plastering in their range of services. When they find someone good, they hang on to them as a valuable commodity. Plastering, like every trade, has some highly skilled craftsmen and women, but many more who are still learning or just don’t take care to get it right.

From mixing up the plaster to preparing the surface to applying a smooth coat, there are many things to take into consideration. A good company will understand this and respect their plasterer’s art. For example, the humidity and temperature on the day of plastering will affect the consistency of the mix and the drying time. If plaster dries too quickly it will crack. The characteristics of the surface being plastered are important too. It won’t stick to a damp or glossy surface. Knowing how to get all of these elements right is a skill that most people aren’t aware of.

The part of the job that people do notice is the speed and art with which the plaster goes onto the wall or ceiling. With quick and steady sweeps of the arm, a smooth surface is created. Watching this being done well is an impressive sight and has inspired many amateurs to embark on their own projects, with disastrous consequences. Another sign of good plastering skills is the care he or she takes to avoid creating a mess. It is important to take the time to lay out dust sheets, loosen sockets and switches and vacuum the floor after you’ve finished.

Often a project such as an extension or a renovation will involve several tradesmen trying to work around each other to get everything completed in time. Plastering is one of the final tasks and cannot be done until the electricians, plumbers and joiners have all done their bit. The building services company is usually in a hurry by the time it calls in the plasterer, so availability is crucial.

Most people appreciate the skill and art of plastering once they have seen both good and bad examples.

Saturday, March 2, 2013

Venetian Plaster – Its History and Modern Use



Venetian plaster is enjoying a popular revival with the modern renaissance of Italian wall finishes. These finishes while new to some, possess a lineage dating back thousands of years to the early civilizations of Mesopotamia. Unrefined clay plasters were replaced with a mixture of raw lime and crushed limestone. These plasters were sometimes painted with lime paints or indeed used as a base for more elaborate frescoes.

From the remains of the Roman villas of Pompei and other excavated buildings of the time, we can see how the use of these plasters had spread and changed. The Romans knew the benefits of using burnt lime which was than was then slaked (properly mixed with water) and then left to age so as to improve workability. Much of their techniques have been learned from the writings of Marcus Vitruvius in “De Architecture”. Unearthed in the 15th century it documents the building and architectural practices of Rome 1BC. Walls were plastered with 3 coats of a sand and lime mixture followed by 3 coat of a fine marble dust and lime mix to make a smooth polished finish. Whilst the plaster was wet, colors were then introduced to provide a strong, easy to clean decorative surface.

It was the rediscovery of these practices that gave way to their widespread use in 15th century Venice. The lagoon area of Venice had an abundance of wealth and a newly found appetite for classical architecture. At the time, transporting sand around the lagoon was difficult and expensive, there was also an abundance of waste terra cotta from the brick industry and recycling of old roof tiles. So plaster renders were made instead with ground terra cotta and hydraulic lime to make a highly breathable surface well suited to the damp atmosphere of the lagoon area. There was also a great deal of stone and marble waste, this was then ground, combined with lime to create fine plaster finishes or Marmorino. These were often left white to mimic the stone of Istria (modern day Croatia) which was favored by Venetian builders, or painted with frescoes to mimic more exotic marble. Another favorable outcome for the sinking city was that the weight of the Marmorino was considerably less than the classic Roman style of using slab pieces of stone or marble.

Interest in Venetian plaster diminished from the late 19th century until the more recently with their use by renown architect Carlo Scarpa in the 1950′s, 60′s and 70′s. At the moment there is a worldwide resurgence of Venetian plasters being used internally and externally on public buildings, new offices, shops, hotels, and private residences. Whilst some plasters are now made with synthetic acrylic resins. Many still hold true to the original recipe of lime and marble powder, with the inclusion of adhesives so as to be used on modern building surfaces such as drywall.