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Quality Service Since 2001

Three reasons why you should not paint K Rend

K Rend coated properties look great. The different colours available can really brighten up a modern housing estate. However, after a few years algae will start to grow on the surfaces. Next, lichen and moss growth with develop, leading to an infestation of biological growth on your once bright rendered property. At this stage property owners are faced with a dilemma: Should you, and can you paint over coloured render (K Rend, Weber, Monocouche, Sto, etc)?  This article will discuss thee reasons why you should not paint K Rend, as well as other types of through coloured render.

render cleaning

Reason 1 – Biological growth needs to be killed

The staining found on coloured render after a few years are usually the results of biological growth. Some contractors will suggest painting over the stains to hide them, leaving the surface with a fresh painted look. This will look good for a small amount of time. However, if the biological growth is not killed before applying the paint the integrity of the paint will be compromised. Within 6-12 months the algae will growth back through the paint, causing it to flake and peel away from he surface. If this happens the paint will need to be removed using chemicals and high temperature steam cleaning equipment. This is a very costly process, just to take the owner back to stage one. 

But what if the algae, lichen and moss are pressure washed before painting?

This will remove the surface contamination to a level that can look quite clean. At this stage, it could look like it it ready to paint. But beware! Although it may look clean, the algae is still alive on the render. This of it this way: You want to remove the grass from your garden. If you simply cut the grass it will return (in fact cutting increase the growth rate). Instead you would need to kill the grass, or remove it to stop it returning. This is the same approach needed for algae, lichen and moss removal. A light cut, or pressure wash will just encourage the biological growth to return. However, killing the growth will ensure the algae, lichen and moss cannot grow back again.


Reason 2 – Painted properties need to be repainted every 5 years

Granted, all buildings need maintenance. Whether you choose to paint your coloured render property or clean it maintenance is vital. However, to paint a property safely scaffolding will be needed. Ladder use should only be for short duration work or for access. So painting from a ladder unsafe and an accident waiting to happen. For a three bedroom house scaffolding costs are around £900 – £1,150 per week. This is before you look at paint and labour. Also, painting can be weather dependent, so it may take a couple of weeks to carry out the preparation and painting. This means the price to paint the outside of 4 bedroom house will easily be several thousand pounds. This process would need to be repeated every 5 years or so to keep your property looking fresh.

Compare that to cleaning K Rend (other types of coloured render – Parex, monocouche, Weber, Sto, Etc,). The cleaning process can often be carried out from the ground using telescopic cleaning poles. We often clean to 3 or 4 stories without the need for scaffolding or cherry picker. The costs of cleaning your property are far less than the costs of painting rendered surfaces.

Reason 3 – Your render needs to breathe!

Yes, your render needs to breathe. If your rendered property is painted with an unbreathable paint it can lead to major problems. Not only can the paint flake off the surface and bubble in areas, it can also lead to damp inside you’re property. However, if no paint is applied to the surfaces the render will have the finish it was designed to be left with.  – Three reasons why you should not paint K Rend.

Should you ever paint your K Rend?

We suggest that you do not paint your coloured render. Hence this article – Three reasons why you should not paint K Rend. However, there can be occasions where painting would be needed, but only as a last resort. Some of these reasons are:

GRAFFITI – We offer a graffiti removal service, but when a dark spray paint has been sprayed onto a light K Rend, or other through coloured render surface and left for some time is it unlikely that all the paint will be removed from the render. On this occasion it is usually bets to repaint the render.

HEAVY CARBON DEPOSITS – There are some occasions where heavy carbon sulfation is present on the surface of rendered properties. This is particularly common in busy inner city areas, and on Sto Render finished properties. When this is the case the remove process for carbon deposits may not be suitable for the environment, due to the chemicals needed for the cleaning process. On this occasion painting is usually necessary.


What is the alternative?

Professional render cleaning

We have carried out professional render cleaning for around 10 years. In that time we have developed our equipment to make sure we offer the best level of service to go alongside our extensive experience and knowledge of the service provided.

What is softwashing?

Quite a few companies have started to add ‘softwashing(soft washing)’ to their list of services. The usual types of companies adding this service as an add on are window cleaners, gardeners and handymen. Softwashing is cleaning a surface with just chemicals. The process may vary slightly from company to company, but ultimately it involves spraying a cold cleaning chemical solution onto your render (roof or other surface) and allowing the chemicals to do all the work.

Does softwashing work?

It can, to an extent. For very mild cases of algae growth Softwashing alone can work well. However, this is not always the case. For example: Imagine you wanted to clean a dirty cup with mold growing on it.

Would a rinse under cold water tap clean your cup sufficiently? No.

How about if you sprayed some washing up liquid on it too? No.

The only way to clean your cup to an acceptable level would be to use hot water, a cleaning solution and scrub it. You would also probably want to use boiling water.

So how does a professional render cleaning company clean your coloured render(K Rend)?

Step one – A chemical solution is applied to the surface. This should be used using warm water when the weather is below a certain temperature.

Step two – A top up of chemical solution is applied to heavy infected areas of algae, moss and lichen.

Step three – After sufficient dwell time, the render should be lightly steam cleaned with low pressure and a wide fan nozzle. This will take off the build up of algae growth. Also lichen and moss growth (now killed and softened by the chemicals) can be lightly steamed off.

Step four – Steps one to three can be repeated when needed for heavy growth.

Step five – Application of a biocide. A Biocide then should be applied to keep the biological growth at bay for as long as possible.


If all these steps are followed your render can stay clean for up to 6 years before a top up clean will be needed. All this at a fraction of the cost of a new paint job.



If you prefer to speak to someone call us on 0800 6101 275 and we’ll be happy to help.