Grout: the discolouration debate

on 30 June, 2014

As colour variations of grout continue to grow, and darker grouts become more popular, the discussion around grout discolouration is a growing issue for many merchants and their customers.

It needs to be understood that discolouration is not an inherent characteristic of the product. It is often thought that it’s due to a manufacturer error, when in fact it concerns environment and application – it can happen even with relatively minor application errors. However, there are certain precautions that can be taken to minimise the likelihood of it occurring.

Temperature is a contributing factor. When it’s colder, it’s common to experience more problems with efflorescence because the drying time is increased. Visually this will often take the form of a surface stain, discolouring the pigmented grout during the setting or drying out period, creating light ‘patchy joints’. The temperature/drying time relationship is simple – yet something that is often overlooked.

It’s also important to consider that efflorescence is not damaging to the grout and the effect is purely aesthetic. Even if the efflorescence deposits disappear with washing, they may reappear after drying, but should diminish with progressive washing. The most effective treatment is to increase the frequency of washing until the deposit ceases.

So what can we do to prevent this and provide some longevity? Firstly, it’s crucial to make sure a professional fixes your tiles – something that is often forgotten by eager DIY enthusiasts. A professional understands the crucial mix ratios and knows exactly how much water and powder to mix. If excessive water is added to the grout at the mixing stage, salts will migrate to the grout surface. A professional will also understand the risks of using too much water when washing down the tiles after grouting.

If customers have experienced grout discolouration in the past, some handy hints to remove efflorescence can be passed on. Firstly, pre-wet the grout surface with water, and then:

  • A suitable proprietary cleaner may be used, however this is dependant upon how heavy the deposits are, so use at a stronger concentration or undiluted if required
  • Apply with a stiff bristle brush (scrubbing brush) or emulsifying pad and distribute immediately
  • Leave on the surface as per manufacturer instructions, but do not allow to dry
  • Work cleaner into grout surface again
  • Wash off with plenty of clean potable water
  • Repeat where necessary.

Knowing how to avoid discolouration can be turned into a selling point for merchants to pass onto their customers, to then relay to the homeowner. Follow these steps and you’ll be one step closer to grout perfection.

Debi Boulton is brand manager of Dunlop.

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