How to ensure monocouche colour consistency

Ensuring colour consistency in monocouche

There are several factors that can affect the final cured shade of monocouche render, but it is usually conditions on site that have the greatest impact.

Here are some of the most common mistakes that can impact monocouche colour consistency and how to avoid them.

What causes monocouche colour inconsistency?

Fortunately, colour discrepancy will not affect the performance or durability of the render; it is purely an aesthetic issue. But it can cause complaints which are tricky to resolve.

Any problem with colour consistency is usually caused by operative issues such as:

  • Using different batch numbers
  • Timing of application
  • Delays between finishing dates
  • Changes in application procedure
  • Issues in the substrate

How can these problems be avoided in the first place?

NHBC Standards Chapter 6.11 provides a lot of advice on the most suitable weather conditions and other requirements for a successful render application.

Here also are Weber’s top tips for achieving a good colour consistency with your monocouche render:

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    1. Use the same batch number

    As with any naturally formed product, colour shade may alter between batches. Check the batch number before mixing and if they are different, mix the products together to ensure colour continuity. The material required for completing adjoining panels or elevations should all be from the same batch product number or be thoroughly dry mixed together before use.

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    2. Complete walls in close proximity in the same time frame

    Plan your rendering work carefully so that any wall panel and any areas next to it can be completed in a progressive sequence. You need to try and get them finished together. Any delays between finishing dates may contribute to differences in appearance between the panels.

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    3. Use the same application methods throughout

    Any changes in application procedure can result in shade variation between rendered bays.

    Whenever possible, the panels should be finished on an external angle. When mixing the monocouche render product, getting consistency in the volume ratio of water to product is key.

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    4. Prepare the substrate

    The background needs to be reasonably aligned so the render thickness is relatively consistent. The wall should be made up of similar materials that have the same behavioural qualities, particularly suction levels, to provide equal drying of the render. Condition, consistency and the moisture content of the supporting substrate will affect the drying and curing of the product. Protect backgrounds from either becoming too damp, cold or saturated, or too dry, porous or warm, before you start work.

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    5. Scraping

    The time that the render is scraped within the setting process is critical to the finished shade.

    The earlier the product is scraped, the deeper the texture and darker the colour shade. Scraping later will give the appearance of a much lighter colour shade.

    This point of material set should be kept consistent throughout the works, especially when it comes to adjacent panels.

What remedial action should be taken to fix colour inconsistency?

If a remedial solution is necessary, an application of webersil P - a high-performance mineral paint that gives long-term durability and performance - will resolve this problem.  Providing that the monocouche render is clean, dry and sound, a direct application of the webersil P is appropriate.

Step one: the first coat of webersil P should be diluted with 10%-15% clean water and the paint then applied with a medium pile wool paint roller.

Step two: 24 hours later, a second coat should be applied. This should be applied undiluted. The application should be in a criss-cross pattern ensuring that the paint is applied evenly minimising any effect on the scraped texture of the monocouche.

What does Weber do to prevent colour inconsistency in its products?

Weber’s monocouche renders are made from a formula containing selection of natural aggregates, blended ingredients and pigments. weberpral M is manufactured to the highest quality assured standards, using modern plant and stringent quality testing. All Weber sites operate to BS EN ISO 9001:2000 and BS EN ISO 14001.

Any questions?

If you're unsure about anything you've read in this guide, please feel free to get in touch with our Technical team who are available to answer any questions you may have.

The team is available Monday to Friday from 8:30am until 5pm.

Simply call (01525) 722 100 (option 2)

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