Protecting render from algae growth and other contaminants

Whilst monocouche render is low maintenance, like any other building facade it is not immune from the gradual buildup of organic growth and dirty deposits or graffiti. Various factors can increase the likelihood and rate of algae formation such as prolonged damp weather, north-facing elevations which receive less direct sunlight, and buildings in close proximity to sources of water and woodland areas.

Common issues and queries you can face

Algae Growth

Organic growth buildup on facades

Over time, facades exposed to the elements will begin to become subject to the buildup of organic growth such as algae, moss, mould, fungi and lichen.


Graffiti or dirty deposits left on facade

With facades exposed to public areas, manmade dirty deposits or graffiti, negatively affecting its appearance.

Step-by-step guide

  1. Clean facade

    Ensure the facade has been cleaned sufficiently with weber CL150 to remove any existing dirty deposits or organic growth. 

    Even if there are no visible signs of dirt or organic growth, it is important to kill spores before applying weberend protect. Use our guide to render cleaning for a step-by-step guide as well as an instructional video.

  2. Prepare substrate

    Existing cracks in facades should be repaired before applying weberend protect – use our guide and instructional video on monocouche crack repair.

    Ensure the surface is not damp and moisture content is below 5% to a depth of 10mm.

  3. Apply weberend protect

    weberend protect can be applied by spray, brush or roller, but when applying onto a highly-textured surface — such as dry dash or roughcast render — we recommend using a low pressure spray.

    Apply weberend protect from bottom to top on vertical surfaces, taking care to ensure the product doesn't run.

    Surfaces must be treated in saturation in 1-3 applications made "wet on wet" within 10 minutes of each other to ensure 100% product effectiveness. The amount of coatings and coverage required will depend on the substrate's porosity. Once a fully-treated surface is dry, weberend protect cannot be re-applied due to a loss of adhesion.

    Please note: You should always test new products on a small, discrete area of the substrate before commencing work to assess the number of coatings required.

    See a side-by-side comparison of render with and without weberend protect

  4. Allow to cure

    Whilst water repellence is evident after initial curing, it can take up to 7 days for full effectiveness to be achieved.

We're here to help

If you have any questions about this process, please feel free to get in touch with our technical team:

Our technical team is available Monday to Friday, 8:30am until 5:00pm.

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