Achieve a same-day scrape in colder temperatures

Weber UK

It is widely acknowledged that one of the greatest challenges for renderers is the UK winter climate.  From October through to spring, rain, frost and limited daylight threaten the quality of the job, not to mention your experience on site.

During the product selection process for winter workings the benefits of cement technology should be considered.  Cement reacts with water activating a chemical setting process and while lowering winter temperatures slow this reaction down it doesn’t stop it.  We always recommend working at 5°C and rising as under this temperature the curing process is slowed down so much you risk unintentional damage from driving rain and knocks as it slowly sets.

When it comes to monocouche rendering success comes down to applying and scraping monocouche at the right time of day.

Why scrape the same day?

When the days are short and the nights are cold, it’s tempting to apply monocouche in the late afternoon and leave the scraping until the following morning. However, scraping on the same day has a whole host of advantages.

Easier scraping:

If the weather is cold or damp during the night, scraping first thing may not be possible, affecting your plans for the rest of the day. If temperatures are unusually high, on the other hand, you’ll spend more time scraping as the render will be harder. Most monocouche render is easiest to work with just a few hours after it’s been applied.

A more consistent finish:

Scraping render at different points of the set is the easiest way to create colour problems. While early scraping will produce a darker shade, a late scrape will make the finish much lighter. Both ends of the scale will also affect texture of the monocouche render.


Scraping on the same day is a great way to increase productivity. It means you can make one visit to the scaffold, complete the work in a single day, and not have to come in on Saturday if you spray on Friday. It also allows you to get a job done quickly when the weather window is limited.

How to achieve a same-day scrape in all weathers

You might be thinking all of this is easier said than done. So now you know why scraping on the same day is the best option, how do you actually achieve it?

To achieve a same-day scrape in cold weather, all you need is weber accelerateur monocouche. weber accelerateur monocouche is a colourless liquid that is used to replace a proportion of the product gauging water.  It is 100% pure and will not damage the colour of the render or your machine.  Once applied, it accelerates the initial set so that at 5°C, the scrape time will be the same as for standard monocouche at 20°C (approximately 4 - 4.5 hours) meaning the render is less susceptible to lime bloom.  This puts you in control of the render rather than the other way around, and means you can continue with same-day scraping all year around.

weber accelerateur monocouche comes in 20 litre drums and requires an addition rate of just 0.1 litres mixed in the gauging water per bag of weberpral M. This means one drum is sufficient for approximately 200 bags of render, which will cover around 200m².  Please always check the product datasheet as misuse can result in unintended consequences.

To learn more about using this product effectively, contact our technical team at or call 01525 718877 option 2, or make an appointment with your regional application manager, who can visit you on site to provide a tool box talk on this subject.

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