Decoration - Paints

Paints have been used throughout history to provide colour, style and protection to virtually every surface in houses. They need to be liquid, with varying degrees of viscosity, in order to enable effective application. Once applied, they need to dry rapidly to form opaque and durable finishes to both internal and external surfaces of houses.

Paints consist of three elements:

   -Pigments – which impart colour and opacity (i.e. the prevention of light penetrating through to
the substrate). This is useful in protecting from UV radiation and masking previous colours. In the past, naturally occurring and metal-based pigments were common; nowadays synthetic pigments offer both economy and reduced health risks.
   -Binders – resins which are the film and body-forming component of paint, binding the pigments together to give the paint ‘body’. In the past, milk, bones, lead and various oils were commonly used. More recently, synthetic resins such as vinyl, polyurethane and alkyds predominate.
   -Dilutents – in which the pigments and binders are suspended. In the past, natural and man- made solvents, such as turpentine, white spirit, alcohol, etc., were common. Nowadays water is increasingly common as a paint dilutent as there has been increasing regulation concerning the environmental and human health impacts of volatile organic compounds (VOCs), such as white spirit and the other solvents mentioned above. Once applied, the dilutents evaporate leaving the pigments and binders as a surface coating.
Paints are designed and selected to provide differing levels of surface quality and protection according to a number of factors:
   -the degree to which they are exposed to external weather conditions: this impacts on
the number of coats required and the nature of the paints themselves
   -the nature of the surface to which they are applied: generally, oil-based paints were used on
timber joinery internally and externally, water-based paints on masonry and plaster; however, this distinction has become less and less relevant because of the increasing use of water-based paints, related to concerns about VOCs
   -the likely degree of mechanical damage/wear and tear: doors, windows and skirtings potentially suffer greater mechanical wear and tear than ceilings and walls, for example. This impacts on the selection of the finish of the paint itself: essentially, gloss finishes provide better weather and mechanical protection. Matt paints provide less protection and are less washable but, as they contain less binder (the expensive part in modern paints), they are generally cheaper to produce. Matt paints also mask surface irregularities better than glossier finishes.