Why is my render going red?

Modern colour through renders are great in most respects. They add instant colour to a building, give it smooth modern lines and are virtually maintenance free.

The term “virtually maintenance free” is where the problem lies with these modern building coatings. I have yet to find a surface finish that will maintain its appearance in our wet but mild climate without some form of care or cleaning. Even the so called “self cleaning glass” fails to keep naturally clean and requires periodic washing with pure water.

So back to the question in the title, why is my render going red? Take a walk in to the countryside and you will see on any rock face or man-made wall, colonies of red and green algae, lichens and mosses. These organisms build upon one another in a symbiotic relationship and they find our building exteriors a perfect representation of their natural habitat. Our homes and work places have always had these organisms present to some degree, but older finishes such as brick do not show them easily unlike the pastel shades of render.

We have reached a perfect storm with the problem of colonisation by red and green algae making buildings look unsightly and an increased need for render cleaning and maintenance programs. Modern renders such as K-rend, Monochuce and Sto have a textured and somewhat porous surface profile. This allows rain water to remain present on the surface for longer and when combined with improved air quality and increased insulation values being installed in to buildings which prevent heat loss through the walls, this in turn slows down the exterior drying process.

Thus the perfect environment for red algae to thrive is created and the unsightly red algae staining that is seen all around the country takes hold. This combined with the miss selling of “maintenance free” means our cities and towns are turning red. Render cleaning using the low pressure softwash method is the perfect solution to this modern problem, if you would like to know more on how we can clean your render please click the link.

Does my render need painting?

It is a common misconception that modern colour through renders are maintenance free or need to be painted if they have not been properly maintained. Although you can paint renders such as K-Rend or Monocuche should you wish to change the colour, it is not necessary to do so if it is dirty or colonised by red or green algae.

Soft washing was developed to deal with the problem of how to clean these often soft rendered surfaces. Through careful application of the softwash chemical at low pressure great results can be achieved and 9 times out of 10 your render will look brand new. So how do you clean the render?

Render cleaning is undertaken using low pressure pumps and specially adapted poles, brushes and spray heads. In many instances the render is first pre-wet before the application of chemical. This helps prevent the chemical evaporating from the surface to quickly, especially on warm sunny days. It also prevents over saturation of the render, the chemical gets where it needs to be in the right amount and concentration.

The softwash solution is then sprayed or brushed (brushing helps break the biofilm) on to the surface and the cleaning process begins. In some instances the wall may only require one application of the softwash chemical, but this is dependant on the level of contamination and the types of biological matter that is present. Once we have achieved the required level of cleanliness, the rendered wall is thouroghly rinsed with fresh water to flush away all contaminant matter and any remaining chemical.The render will now dry and return to its original installation colour, its surface and substrate are now sterilised and will take sometime to re-colonise.

Now what? We recommend that your render is treated on a regular 18 -24 month cycle with our specialist biocide treatment. This will prevent the return of the unsightly red and green algae staining and keep your render looking like new.

Power washing cobble block driveways and paths

Cobble block driveways and paths fit in well with most gardens and look great when first installed. As time passes they slowly start to be colonised by algae and lichens on the surface, with moss and weeds filling the joints. That once pristine path or driveway no longer looks as neat as it once did, it is time for a power washing service.

With the right techniques, equipment and chemicals, any tired looking driveway can be restored. Let me take you through my process of power washing cobble block paving.

  • Step 1, the driveway or paths are cleared of any debris such as leaves, twigs and any other rubbish that might have blown in to the garden.
  • Step 2, if the driveway is nasty and green with plenty of algae contamination I might first pre-treat the surface with a softwash solution to lift and soften up the lichens. This will also help remove much of the algae instantly. If the drive is not in poor condition I’ll skip the pre-treatment and go straight to step 3.
  • Step 3, is where the power washing begins. The condition of the substrate to be cleaned is assessed and the correct level of pressure set on the machine. The edges of the driveway or paths are now washed using a lance fitted with a turbo nozzle. This really helps lift the weeds and old sand from the joints.
  • Step 4, I now use a flat surface cleaner to methodical clean the main body of the cobble block driveway. The flat surface cleaner can clean a strip 18 – 20 inches wide in one single pass. This reduces the fatigue on the operator and helps keep down the mess from splatter.
  • Step 5, the driveway is now swept to gather up all the moss, weeds and sand removed from the joints during the cleaning and is now washed down using the lance again.
  • Step 6, for that extra little zing on a driveway, I like to post treat the blocks once more with the softwash solution and then rinse down after a 20 minute dwell time. This just adds that extra little sparkle to the driveway.
  • Step 7, once the driveway has dried sufficiently, the joints are re-sanded using kiln dried sand. This helps with the stability of the driveway and completes the overall look and finish. (sanding can be often completed same day during a hot summer, but is more usually done a couple of days after)