How to get a smooth render finish and prevent miss marks

Miss marks

When rendering your home or business the aim is to achieve a neat and sleek finish that adds to the aesthetics of the building. However, you may have come across a job where you’re left with a finish that is inconsistent in terms of colour and texture.

Understandably, this can cause frustration for those who have carried out the work and those who own the property. Luckily, there are simple solutions to tackling this issue.

Preventing miss marks

You are probably wondering how to get a smooth render finish, prevent miss marks and ensure that the end result lives up to your expectations.

To achieve a consistent colour and texture with a scraped render it is imperative that all the cement rich laitance is removed uniformly. This part of the finishing process is typically done between 5 and 16 hours after application depending on the time of year and weather conditions.

What is laitance?

Laitance is a weak, milky layer of cement and aggregate fines on a concrete surface which occurs during settlement/compaction. This occurs when bleed water migrates to the surface, which brings particles of the render with it. The laitance is formed once the water evaporates. When left to harden, it can affect the drying process and the appearance and texture of the render.

Ensuring a smooth surface

The surface should be scraped with a circular action keeping the scraper flat and under even pressure. To avoid scoring the finished surface, it is important that all cement rich skin/laitance is removed uniformly during this scraping process.

We would encourage the use of an I section rule to assist with finished alignment as any misses in scraping will result in an inconsistent finish in the render – they’ll show as light patches and are smoother with little or no texture. This is a workmanship issue and can be avoided by adopting a good practice of brushing down the area to identify any miss marks; these can then be rectified before the render dries.

Remedial advice

Hard laitance removal can be done with a carborundum stone or saw blade and then painting over with webersil P - a high-performance mineral paint that gives exceptional long term durability and performance. It is anticipated that the use of this product will not detract from the low maintenance benefits of the weberpral monocouche render. Providing that the monocouche render is clean, dry and sound, a direct application of webersil P is appropriate. The first coat of webersil P should be diluted with between 10% and 15% clean water and the paint then applied with a medium pile wool paint roller.

When the first coat is dry, 24 hours later a second coat is applied, this coat should be undiluted. The application should be in a crisscross pattern ensuring that the paint is applied evenly minimising any effect on the scraped texture of the monocouche render.

We hope that this blog has helped you to ensure that you achieve the perfect finish when rendering in the future!

Contact us

If you have any questions about any of the information we have provided, do not hesitate to get in touch! Our expert team is always on hand to provide you with in-depth advice and guidance specific to you and your needs. Call us on (01525) 722 100, or email us at technical@netweber.co.uk

Our technical team are available Monday to Friday, 8:30am until 5.00pm.

Click Compare to help you choose the right product for your project, if you need further assistance please email technical@netweber.co.uk

Compare