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Discolouration of sealant joints: causes and prevention

Sealants are widely used in both construction and industry. These sealants come into contact with various substrates and must withstand a variety of conditions. Nevertheless, a sealant joint may become discoloured over time, which may be more noticeable with lighter colours in particular. Although discolouration is often perceived as annoying, in most cases it does not affect the performance of the sealant. The main causes of discolouration can be divided into two categories: environmental and usage factors.

Causes of discolouration: Environmental factors

During new construction projects, sealant joints can be imperceptibly exposed to chemicals released during the curing of other building materials, such as fresh paint systems, smoothing plaster or tile adhesives. This contact often occurs during or shortly after application of the sealant, making discolouration most likely and often irreversible.

In addition, some substrates may contain substances that migrate into the sealant, such as bitumen, neoprene or alkaline components. A third factor is using sealants in dark rooms without daylight, which can also lead to discolouration.

Tips to Prevent Discolouration from Environmental Factors:

Do not apply the sealant joints until other finishing products have fully cured.
Ensure adequate ventilation during the curing phase of the sealant.
Use backfilling to avoid direct contact with migrating substrates.
For dark rooms, it is wise to choose a dark-coloured sealant, as these are less likely to discolour.

Causes of discolouration: Usage factors

Besides environmental factors, usage factors also play a role in the discolouration of sealant joints. Common causes include contact with liquids such as detergents, shampoos, shower gels and other soapy products. In addition, gases released from the use of toilet fresheners, candles, scented sticks and even cigarette smoke can contribute to the discolouration of the sealant surface.

How to Prevent Discolouration by Usage Factors:

Regular cleaning with lukewarm water and rinsing the sealant joints helps prevent discolouration.
Make sure the sealant joints are dried well after cleaning.
Good ventilation contributes to an aesthetically pleasing result and extends the sealant's life.

Discolouration: Aesthetic, but not functional

In almost all cases, discolouration of sealant joints is only an aesthetic problem and does not affect the performance of the sealant. This means that the sealant joints continue to perform their sealing function even when discolouration occurs. Understandably, however, aesthetics are important, which is why it is worth avoiding discolouration as much as possible.

At SABA, we base our advice and instructions for use on the most up-to-date knowledge and technology. Although we conduct extensive testing and research, we always recommend that customers and users test our products themselves for their intended use. It is important to follow our advice to ensure an optimal effect of the kit.

If you would like to know more about how to prevent discolouration and which products are best suited to your specific situation, please feel free to contact our experts for tailored advice.

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