Renovation: reason or solution for algae on facade and roof?

Algae on the outer wall are, unlike ivy or wild wine, a rather unwanted and unattractive greening of facades. Many homeowners have to deal with algae or even lichen and moss on damp exterior walls and especially on the side of the house facing away from the sun.

The roof can also suffer from the green microorganisms. In both cases, the rumour persists that the renovation, including roof and facade insulation, is the reason for the algae growth. But this is not true – in fact, renovation can be the solution to the problem.

Facade renovation: reason or solution for algae?

The renovation of the facade is seen by many as a reason for algae, mosses, lichens and other unwanted greening of the outer walls, because a low temperature is held responsible for it.

However, the temperature of the wall as well as of the surroundings does not play a role in the development and growth of the algae from a certain point on. One of the most important factors is the humidity of the facade and its surroundings.

If there is no possibility that the outer wall can dry out, for example because trees and shrubs keep out sunlight and draughts, then algae growth is encouraged.

If the wall only dries completely when sufficient heat is generated inside the house, this is not a reason against, but a very important reason for the renovation and insulation of the facade.

Because it means that the energy efficiency of the building is very low. This means that the residents or users have to heat a lot to keep the interior pleasantly warm, which of course also means high costs.

The money should rather be invested in the renovation of the facade, including the insulation of the facade. All that is needed to ward off algae, moss and lichens is the right exterior material.

Renovation of the facade is neither pro nor contra

The renovation and insulation of the facade is therefore neither a blessing nor a curse with regard to algae on the outer wall, but should be considered solely in terms of the building’s energy efficiency.

And that is where the measures always pay off! However, care should be taken to ensure that the boarding, cladding or plaster that shields the insulation of the façade from the outside fulfils some important requirements.

One or more items on this list should be fulfilled:

  • the facade is free standing and can dry off well
  • the plaster contains minerals / mineral salts which keep algae away
  • the facade was treated with a water-repellent solution

proPERLA products on floor, wall and roof

Our proPERLA products ensure that walls, floors and roofs remain breathable but become water-repellent and dirt-resistant. The surface is protected against moisture and dirt for a long time, so that microorganisms and green growths cannot settle.

This also provides years of protection for bare brickwork, facades of clinker brick buildings, plaster without anti-algae additives and many other surfaces.

Entrances, car parks, hall floors and roofs with different types of tiles can also be treated with the appropriate products and thus protected against (internal) insulation against moisture and algae.

Facade paint with roll-off effect

Neither the facade renovation as an individual measure nor the complete renunciation of higher energy efficiency represents the ultimate against algae on the facade. It is rather the moisture in and on the wall that you should reduce or prevent.

To prevent water from settling on the outside or penetrating into the façade, you should therefore use a facade paint that allows water to run off during renovation (or as a medium-term alternative). Our proPERLA facade paints are particularly suitable for this purpose. Here are all the advantages at a glance:

  • Penetration of rainwater is prevented
  • Water is repelled and rolls off the surface
  • The thermal efficiency is increased without or in addition to the refurbishment
  • The outer wall / plaster remains breathable
  • A high opacity provides for an extreme optical upgrading
  • You have a large selection of different colours
  • Lifetime of paint and water resistance is 15 to 20 years
  • Application is possible on practically all house facades

Same principle for other components

Concrete components and floors can also be treated to be breathable against water and dirt thanks to our innovative products. Concrete floors can be silicified and sealed with appropriate systems, preventing water from penetrating centimetres deep.

The treatment also makes the surface nice and smooth – the otherwise porous surface is transformed into an even surface that can be cleaned very easily and quickly. Mosses, algae, lichens as well as dirt and bacteria then have absolutely no chance.

No matter whether it is a residential house, garden or industrial plant, our becoTREAT products provide the ideal solution for the surfaces of your house or company building thanks to their quick application and long service life.

What to do against algae on the facade?

Do you already have algae or other green microorganisms on the outer wall / facade? Then you can fight them with water, a brush and a little muscle effort.

Algae as well as other vegetation à la moss and lichens can be brushed off masonry, plaster and the like quite well. For cases of hardship there are certain biodegradable cleaning agents.

You should never proceed with bare chemicals. However, choose a warm, sunny day for cleaning the exterior wall and make sure that the surface can dry quickly after treatment. Ergo: the removal of the algae from the house facade should take place on a summer morning.

If you need more information on this topic and want to read about the type of soil that, in addition to moisture, promotes algae and mould on the façade, we recommend this guide: Emergence and prophylaxis: Algae and mould stains on the facade of a house.

In this article we have summarized, among other things, the role played by fine dust and other factors in the ambient air. In addition, the dangers of mould infestation for humans and animals are shown.

Conclusion on algae

The algae growth of the facade therefore only takes place if it cannot dry properly and also provides an ideal surface for the microorganisms including pores, dirt and the like.

A possible renovation or facade insulation ensures that the heat is kept inside the house and cannot escape outside through the masonry, but does not exclusively promote the formation of unwanted greenery on the wall.

If you are planning a facade renovation or are looking for an energy-efficient alternative, then make sure you use water-repellent facade paint.

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proPERLA® offers a range of exterior super hydrophobic waterproof paints & coatings designed to reduce energy costs and protect homes.

Through our official network of applicators, we provide services to end customers, ensuring the correct application of our products for your benefit.

Whether you are a professional interested in working with our products, or a customer looking for solutions, contact us for more information.

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