We are often asked: How to remove Red Algae stains from wall render?

How many times have you driven past a house or building with a white exterior?

Only to find that the white surface renders to have been coated with some kind of rusty red covering.

They are primarily extending from the top of the building downwards as if something has spilt down from the roof onto the walls below.

What you are seeing is the effect of red algae on a rendered wall surface, whereby the walls which suffer the most from extreme weather become coated in the build-up of algae. If proper care and maintenance are not undertaken to regularly perform a full exterior clean.

One of the most common questions we get asked is how to keep on top of red algae staining, and whether it is fixable once it reaches the kind of state that many homes are in. In essence, the best way to keep on top of the staining is to invest in a regular cleaning routine – and yes, a red algae stained wall can be saved, but only with a little added help from a soft wash solution.

Cleaning red algae from a rendered wall surface

In this instance, we tend to see a lot of homeowners reaching for a pressure washer or jet wash – seeing their wall as a similar surface to a patio which can be quickly cleaned with a high powered jet of plain water. In fact, the fastest and safest way of clearing a wall of red algae is to opt for a soft wash solution – with the degree of washing reliant on the severity of the algae spread.

• If the algae is a pale red and do not thoroughly coat the surface, you should be able to simply spray the solution onto the surface and then walk away – letting nature run its course with the weather and rain eventually washing away the solution and the algae along with it.

• A more severe case tends to be characterised by darker red staining, which appears to exist in layers rather than a surface coating. This kind of algae staining requires more of a forceful hand, with many professionals leaning towards a two-step approach:

1. Apply the bio soft wash cleanser and brush it into every corner of the surface, helping to loosen the surface layer of algae so that the natural weather can do its job and wash away the worst of the staining.

2. Once the original coat has been washed away, use a secondary soft wash solution to blast away any residue staining and to leave the surface completely clean.

Care should be taken not to scrub too hard at your wall rendering, as excessive force can prove damaging to the surface if you are not careful.

You should also take care not to drop the solution on surrounding plants and surfaces if you can help it, and always wear gloves during application for health and safety purposes.

While soft wash is available for mass-market purchase, we tend to find that homeowners prefer to invest in the experience and help of a professional – especially when it comes to cleaning wall surface at great heights.

Utilising professional equipment and employing years of experience in ensuring the most effective and safety conscious cleaning experience, we at Stardust Cleaning are always happy to provide quotes and guidance on achieving the best results.

Just get in touch for more information.

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