Dammam-based Sigma Paints Saudi Arabia, a leading decorative paints and protective and marine coatings manufacturer, has recently added Sigmaflex Premium to its already extensive range of decorative products.

The new coating has been developed to provide protection and decoration to cementitious exterior substrates that are prone to cracking and concrete carbonation
Cracks that appear on freshly applied cement-rendered substrates are commonly caused by a number of factors, says Yanal Shekem, marketing manager Middle East of Sigma Paints Saudi Arabia
These factors include one or more of the following:
* The accelerated drying of the applied render - most commonly the result of exposure to high ambient temperatures that are typical in the Middle East.
* Settlement of the building, as all new structures are prone to very slight movement or settlement. Construction materials contract when they dry out and the differential contraction of the various materials may continue for a number of months after the construction has been completed.
* Overly-thick application of the render. Cracks occur when the face of the render dries out before the underlying render which creates stresses in the entire render application once it dries.
* The use of poor-quality raw materials and in some instances, materials that contain impurities - for example, desert sand or brackish water - which very often has an adverse effect on the hydration or drying process of the cement render
* Poor mixing of raw materials. When the mixing method adopted does not produce a homogeneous mix of materials, this can result in re-hydration of the cement.
* Re-hydration of the cement, which can also occur when the surface is exposed to a source of moisture, humidity, rain or irrigation water, causing expansion and contraction of the applied render, which results in cracking.
Concrete carbonation
Concrete is alkaline by nature owing to the materials used in its manufacture. The steel reinforcing bars are passivated, or protected from corrosion, by this natural alkalinity, of pH 12 to 13. However, when acidic gases penetrate, this leads to carbonation and a reduction in the alkalinity in the concrete with a pH of less than 9.5. At this pH level, reinforcing bars are no longer protected from corrosion and hence rust forms on the steel bars.
As corrosion of the steel reinforcement progresses, the bars may expand by up to five times their original size, resulting in initial cracking followed by the spalling of the concrete cover.
Concerned by the needs of its customers, and in response to the cracking and carbonation issues, Sigma Paints has developed Sigmaflex Premium, following years of extensive research, development and testing in Europe, Africa and the Middle East, says Shekem.
“Sigmaflex Premium is a perfect coating to resolve most of these building exterior issues and is particularly suited to the climatic conditions experienced in the Gulf countries,” he points out.
“It a water-based, pure acrylic, elastomeric coating with excellent UV (ultraviolet) resistance and is easy to apply.  It also has excellent flexibility and elongation properties and has been independently tested and certified by the leading certification body Bureau Veritas, bridging cracks of up to 2 mm.
“Sigmaflex Premium also provides the required anti-carbonation properties for the protection of reinforced concrete and has been tested independently by the University of Dortmund in Germany,” he adds.
Established in 1980, Sigma Paints is an ISO 9001-2000 certified company, dedicated to customer satisfaction. With its own production, storage, research and development facilities in Dammam Industrial Estate, the paint manufacturer supplies the local Saudi market and Middle East markets with its range of high quality paint advice and solutions across the Middle East.