Staying on Quality Street First published in Building Products News, May/June 2002, ©Reed Business Information Australia 2002

©Reed Business Information Australia

A well designed building can be badly let down by poor quality paint, writes Katrina Fox

An architect's reputation is made on good building design. But what happens if, at a later stage, the paint on those buildings starts to flake off, fade or become riddled with mildew?
According to Rohm and Haas Paint Quality Institute Asia Pacific manager Mike Beresford, a poorly maintained building compromises the value of the work the architect did originally and can impact on their reputation in the marketplace. 'The proof of a good design is not just evident after a project is finished, it's how well the building stands the test of time,' he says.

Beresford stresses the importance of selecting high quality paint for a project from the start, as this can add years to the appearance and condition of a building. All paints, whether oil or water based comprise three main components: binder, pigment and liquid, as well as other performance enhancing ingredients. The type and amount of binder is crucial as this affects everything from stain resistance and gloss to adhesion and crack resistance. Water based paints with acrylic polymer binders are considered to have better external durability than oil based paints.

Pigments are finely ground particles or powders which are dispersed in a paint. Prime pigments provide colour and opacity (opaque coverage). Extender pigments provide bulk to the paint at a low cost. These pigments impact on properties such as scrub resistance, stain resistance and chalk resistance.
Higher quality paints have higher levels of prime pigment than lower quality ones. They also have less extender pigment in relation to binder level. This makes them more chalk resistant on building exteriors, providing better colour retention and durability as well as requiring fewer coats.

Liquids carry the pigment and binders. In oil-based paints, the liquid is a paint thinner. In water based or latex paints, as they are sometimes called, the liquid is water. Top quality paints have less liquid and more pigments and binders, known as solids. A can of quality paint s a higher volume of solids and less water than ordinary paints. So, if a top quality paint and an ordinary paint were applied at the same spread rate, the top quality paint would dry to a thicker paint film due to its higher solids content. A top quality paint contains 35 to 45 per cent volume solids, while an ordinary paint contains only around 25 to 30 per cent.

Other ingredients used at low levels to provide key properties include mildewcide to keep mildew in check.
According to Beresford, 85 per cent of architectural paint in Australia is water based. 'Of these, the acrylic ones are the best performers because they have a very high resistance to UV radiation so they don't break down quickly in our high intensity UV whereas by their nature oil based paints do,' he explains. 'The other advantage of acrylic paints is that they have a good balance of performance properties - they provide good moisture resistance and washability over time on the interior of buildings, and on the exterior they have good adhesion to a wide variety of surfaces.

'Nowadays an architect can confidently select one of these type of paints to use on masonry surfaces, concrete render and plasterwork as well as timber, metals and so on.'
This flexibility makes acrylic paints appropriate for most types of building, whether they are commercial structures or residential properties, Beresford adds.

In addition to providing protection to a building's surface, top quality paints also offer an extensive range of colours and textures to add aesthetic value to a project. Even from an environmental angle, high quality paints win hands down. 'There is an understanding in the industry that coatings need to be continually improving in their environmental sustainability and suitability,' Beresford says. 'One way this is already happening is a move away from solvent based paints to water based ones. This is a significant improvement in terms of the amount of solvent being emitted into the atmosphere. 'Water based paints have much less solvent in them than solvent based enamel paints, and the kinds of solvent are also far less benign.'

As far as cost goes, Beresford admits that an initial higher outlay is required for these higher quality paints, but the cost savings are made in the long term. 'Those paints which are designed to give very high levels of performance will provide a greater cost effectiveness per year or over the lifetime of the project,' he argues.
Although it is relatively easy to refurbish the paint on buildings at a later stage, it is generally more expensive and time consuming than using higher quality paints from the start, Beresford adds. 'Some people may say the architect is responsible only for the delivery of a project design upfront rather than its lifetime performance.But the aesthetic performance and durability of a building over time all speak about the quality of the specifications put in upfront.'

Building Products News magazine goes out to architects and building designers in Australia. This article is the copyright of the publisher, Reed Business Information and appears here with their permission. For more information on the magazine, visit Reed's website at http://www.reedbusiness.com.au