Modern renders gently cleaned with the Softwash system

By Published On: June 17th, 2021

Modern renders cleaned with Softwash cleaning system

We use a revolutionary, non-aggressive exterior cleaning system, called Pro Softwash  It’s ideal for cleaning modern render, pebble dash, concrete, rooves and tarmac.

Modern, self-finished render has become popular over the past 30 years due to its low maintenance properties, value for money and faster installation to suit modern construction constraints. These renders don’t require re-painting, however they are a great breeding ground for lichen, algae, moss and mould.

Removing unsightly growth on render

Increased insulation in modern buildings reduces the transfer of heat to external walls and surfaces, leading to more moisture being left on exteriors. This build-up of moisture leads, in time, to algal and fungal growth. Additional design features such as flush, crisp line facades without shadow gaps at the parapet or sills will inevitably lead to such disfiguration in our wet climate.

Red and green algae leave unsightly dirty marks and are very apparent on various renders and concrete surfaces all over Ireland. Aggressive cleaning methods – such as power washing or harsh chemicals – can damage the surfaces and actually hasten the regrowth of fungus and algae. Pressure washing will increase the porosity of the render, meaning that more moisture will be able to penetrate the surface, which will contribute to regrowth.

Cleaning student residences at UCD

We recently used the Softwash system at UCD to clean unsightly growth on the white render of their student residences.

The Pro Softwash system uses a combination of environmentally friendly biocides, applied in a non-aggressive manner with a gentle wash. Although highly concentrated, the biocide is a soft, pH neutral treatment that controls the growth without damaging the surface or the environment. The biocide kills and disperses the growth. Black spot (a lichen) will need to be removed with a soft brush.

The dwell time – how long the biocide needs to be left on the wall to have an effect – depends on how deep the growth is, how long it has been allowed to grow and the surface’s exposure to very wet and harsh climates. Dwell time can therefore vary from a few hours to several days. Our trained operatives will determine this once on site. In some cases, where render is exposed constantly to very wet elements, a second application may be needed. Once the treatment is complete, the biocide is gently removed using low pressure water.

A long-term solution for render

Results won’t be as fast as with power washing – red algae can take up to 10 days to disappear after treatment as final residue is washed off in the rain. However, with the Softwash system re-growth is prohibited. The correct use and application will eliminate algae, mould, mildew, moss, fungus and lichens. This is not the case with regular washing.

Render cleaned by P Mac at UCD Campus

After: great results from the Softwash

The Softwash system can be applied to soft external surfaces such as external insulation, cladding and stucco. It will not harm decorative mouldings on buildings and walls, including coloured K-Render finished plaster. With correct use, renders and external surfaces are restored to their original condition.

Read more on Façade cleaning

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Our legacy is quality projects we can be proud of. We value the inputs of our customers, our team and our supply chain in reaching positive outcomes. Health and safety to our people and the public is a priority for us and without compromise.

If you are working on a similar project we would love to hear about it. Dont hesitate to call us or send in the details of your project through our contact page at

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