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Can Render Be Jet Washed? - Render Maintenance


Over time, a building's exterior will be exposed to organic substances and pollutants. The accumulation of mould, algae, exhaust fumes and carbon pollutants can leave stains and discolouration on the rendered facade. The heavy staining creates a ghastly sight of green, brown, and black stains – hardly the welcome any visitor or employee would like to see upon their arrival.

Treating the stains sooner rather than later is best advised. Not only will it restore the rendering to its former glory and prevent vandals from targeting what appears to be a poorly maintained building, but this will also remove harmful substances from the render itself.

Algae and carbon pollutants can cause long-term damage to the render if left untreated. Furthermore, the stains become more challenging to remove the longer they are left as the contaminants penetrate further into the brickwork.

Prospective clients will often ask the team at Spectrum if the render can be jet washed. Although this seems like an easy and cost-effective solution, it can cause more damage.

This blog will explore some of the reasons why you should avoid using a pressure or jet wash as your render cleaning method and which alternative methods are best to use instead.

What can happen if a pressure washer is used on render:


Pressure Washing Strips the Rendered Surface Away

Using a pressure washer is ideal for stone and concrete surfaces but not for render. The pressure is too intense for the render and ultimately strips away the surface from the wall. Even shaving a mm or two off the rendered surface will result in a thinner render, creating cracks, brickwork falling off and an uneven finish. The damage will result in more time and money spent to fix the problem.

Pressure Washing Etches the Rendered Surface

Once your render becomes etched, it will always show. A first look after the pressure washing may lead you to believe the job is complete, but a closer inspection will soon show etching has appeared on the render. The etching damage will become more prominent as algae and moss grow back. The only solution to fix this problem will be to re-render the exterior.

Pressure Washing Does Not Solve the Problem

As we mentioned before, the pollutant and organic growth stains penetrate the brickwork. Using a pressure washer does not get to the root of the problem, and so while blasting away the exterior will look like a job well done, the organisms will still be able to breed as normal. You will be back to square one in a matter of weeks.

What Should Be Used to Clean Render?

Low-pressure steam instead of high-pressure jet washing is the perfect method to clean rendering. This technique protects the rendered surface, gently removing pollutants and organic substances while leaving the surface looking new. Indeed, by killing the bacteria that has been growing on the render, the building will stay cleaner for longer.

Cleaning render without consulting with a professional company can lead to irreparable damage. Property managers and building owners need to ensure the contractor of their choice fully understands the properties of each render to treat it correctly. What makes it even harder for property managers and building owners to take on this work themselves is the confusing disparity between advice provided by rendering manufacturers. For example, K-Rend requires a specially formulated cleaning solution to be gently applied that effectively kills organic substances to prevent their re-growth. (For more information on cleaning K-rend, read our dedicated blog post here)

Spectrum is a specialist and professional cleaning contractor that deploy a unique technique to restore rendering back to its former glory. We use a unique biосidе explicitly mixed fоr еасh type of rendering and then apply a steam wash. We designed our four-stage P.A.S.T. process to clean and restore render, including K-Rend, Weber, Sto and more, to a like-new condition with no risk to the substrate. The Spectrum team are happy to provide a consultative approach to clean your render, even going as far as producing a free sample to demonstrate the effectiveness of their treatment.

Should you spot any discolouration on your render, it is vitally important to treat it as soon as possible to prevent the staining from spreading. Contact us today to find out how Spectrum can help clean and restore your building's rendered facade.


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