Green deposits on facades are a common problem for homes and commercial buildings in Overijssel and Gelderland. Due to the humid climate in these regions, algae, mosses, and lichens easily develop on exterior walls, which not only affects the appearance of your building but can also cause damage to the facade material over time. In this article, you will read everything about the causes of green deposits, the risks to your facade, and which methods are most effective for removing green deposits from your facade.
What are green deposits and how do they form?
Green deposit is a collective name for various organisms that can settle on facades. This mainly concerns algae, mosses, and lichens that attach themselves to porous surfaces such as brick, concrete, and natural stone. These microorganisms thrive in moisture, shade, and a lack of direct sunlight.
In Overijssel and Gelderland, the climatic conditions are particularly favorable for the growth of these organisms. The relatively high humidity, regular rainfall, and moderate temperatures create an ideal environment. Facades facing north and west, which receive less sunlight and remain damp longer after rain showers, are especially susceptible to green deposits.
Factors that promote green deposits
Several factors contribute to the development of green deposits on facades:
- Orientation of the facade: North and west facades receive less direct sunlight and dry more slowly
- Environmental factors: Proximity to trees, shrubs, or water increases humidity
- Material type: Porous materials such as untreated brick and concrete are more susceptible
- State of maintenance: Damaged mortar joints and cracks provide extra attachment points
- Air quality: Dust and pollution on the facade serve as a breeding ground
Why is it important to remove green deposits?
Although green deposits initially seem to be primarily an aesthetic problem, there are good reasons to tackle them in a timely manner. The organisms that cause green deposits can damage your facade material over time.
Damage to facade material
Algae, mosses, and lichens attach themselves to the surface of your facade and slowly penetrate the pores of the material. During periods of frost, the moisture retained by these organisms can freeze and expand. This process, known as frost damage, can lead to flaking, cracking, and crumbling of the facade material.
In addition, some organisms produce acids that can affect the surface of natural stone and concrete. Although this process is slow, it can lead to significant degradation over a period of years.
Deterioration of pointing
Mortar joints are particularly vulnerable to green deposits. The organisms settle in small cracks and irregularities, causing the pointing to deteriorate faster. This can lead to leaks, moisture problems, and ultimately costly renovations.
Depreciation of your property
A facade with clearly visible green deposits makes a neglected impression. This can negatively affect the value of your property and deter potential buyers or tenants. Regular maintenance and the removal of green deposits contribute to preserving the value of your real estate.
Methods for removing green deposits from your facade
There are various methods available to effectively remove green deposits. The choice of a particular method depends on the type of facade material, the severity of the pollution, and your budget.
High-pressure cleaning
High-pressure cleaning is a commonly used method where water is sprayed onto the facade under high pressure. This technique is effective for removing superficial dirt and green deposits on robust materials such as brick and concrete.
Please note: high-pressure cleaning must be carried out with the correct pressure and technique. Too high a pressure can damage the surface, blast out mortar joints, and force water into the facade. This method is less suitable for vulnerable materials such as soft brick or natural stone.
Steam cleaning
Steam cleaning is a gentler alternative where hot steam is used to loosen dirt and organisms. This method is suitable for more sensitive materials and historical buildings. The advantage is that less water is used and the risk of moisture problems is smaller.
Chemical cleaning
For stubborn green deposits, chemical cleaning may be necessary. This involves using special cleaning agents that kill algae, mosses, and lichens and detach them from the surface. This method requires professional knowledge to choose the right agent that is effective without damaging the facade material.
After applying the cleaning agent, it must be given sufficient time to take effect. The facade is then rinsed with water. For optimal results, this method is often combined with mechanical cleaning.
Dry cleaning methods
For certain materials and situations, dry cleaning methods such as sandblasting or sponge blasting are suitable. These techniques use no or minimal water and are therefore suitable for facades where moisture problems must be avoided. However, sandblasting must be carried out with great care to prevent damage to the surface.
Prevention: preventing green deposits
After removing green deposits, it is wise to take preventive measures. This will save you time, money, and inconvenience in the long run.
Impregnating the facade
An effective preventive measure is impregnating the facade with a water-repellent coating. This treatment ensures that water beads off the surface instead of soaking into the pores. As a result, algae and mosses have less chance to settle.
Modern impregnating agents are breathable, which means that moisture from the inside can still escape. This prevents moisture accumulation in the facade. The protective effect of an impregnation treatment lasts on average five to ten years, depending on the product and exposure to weather conditions.
Anti-algae agent
In addition to impregnation, an anti-algae agent can be applied. These products contain substances that actively counteract the growth of microorganisms. The effect is long-lasting and can significantly extend the period between cleanings.
Maintenance of mortar joints
Well-maintained mortar joints are essential for a healthy facade. Damaged joints not only provide attachment points for green deposits but can also lead to moisture problems. Have joints repaired or renewed in a timely manner by a specialized pointing company.
Vegetation around the building
Trees and shrubs that are too close to the facade increase humidity and restrict airflow along the facade. Ensure sufficient distance between vegetation and the facade, and regularly prune back overhanging branches.
When should you hire a professional?
Although small-scale cleaning can sometimes be done yourself, there are situations where professional help is necessary. A specialized company has the right equipment, knowledge of materials, and experience to clean your facade safely and effectively.
Situations where professional help is necessary
- Working at heights: For facades higher than the ground floor, professional equipment and safety training are required
- Historical buildings: Monumental facades require specialist knowledge and adapted techniques
- Vulnerable materials: Natural stone, soft brick, and glazed tiles can be damaged by incorrect treatment
- Severe pollution: With stubborn green deposits or several years of neglect, professional cleaning is more effective
- Combined maintenance: When facade cleaning is combined with joint repair or other renovation work
Benefits of professional facade cleaning
A professional company offers several benefits. The right method is chosen based on the facade material and the nature of the pollution. Professional equipment enables thorough cleaning without damage. In addition, safety is guaranteed by certified employees and the correct safety provisions.
A specialized company can also advise on preventive measures and draw up a maintenance plan. This ensures that your facade remains beautiful and in good condition for a long time.
Costs of facade cleaning
The costs for removing green deposits vary depending on several factors. The surface area of the facade, the chosen cleaning method, the accessibility of the building, and any additional treatments such as impregnation determine the final price.
On average, you can count on an investment between 15 and 35 euros per square meter for professional facade cleaning. Additional treatments such as impregnation or applying an anti-algae agent come on top of that. Although this seems like a significant investment, it outweighs the costs of facade renovation as a result of neglect.
Always request multiple quotes and compare not only the price but also the services offered, guarantees, and references. A slightly higher investment in quality often pays off in the long run.
Frequently asked questions about green deposits on facades
How often should I have my facade cleaned?
The frequency of facade cleaning depends on various factors such as the location of your building, the orientation of the facade, and environmental factors. In Overijssel and Gelderland, we advise carrying out a thorough facade cleaning on average every five to seven years. Facades facing north or in the shade of trees may need maintenance more often. After cleaning and impregnation, this period can be extended to ten years.
Can I remove green deposits myself?
For small-scale cleaning on the ground floor, you can get to work yourself with a high-pressure cleaner or special cleaning agents. Do pay attention to the correct pressure setting and the type of cleaning agent that is suitable for your facade material. For working at heights, large surfaces, or vulnerable materials, we recommend hiring a professional. Incorrect treatment can lead to permanent damage to your facade.
Are green deposits harmful to my health?
Green deposits on the exterior facade generally do not pose a direct health risk. The organisms are located on the outside and do not come into contact with the indoor space. However, green deposits can indicate moisture problems which, if not addressed, can lead to mold formation on the inside. This can cause health complaints. Therefore, it is important to remove green deposits in a timely manner and tackle the cause of the moisture.
Do vinegar or chlorine work against green deposits?
Vinegar and chlorine are sometimes mentioned as home remedies for removing green deposits. Although these agents can have a limited effect on superficial algae, they are not suitable for thorough cleaning. Chlorine can also be harmful to certain facade materials and the environment. Vinegar has too low a concentration to be effective against stubborn mosses and lichens. For sustainable results, we recommend professional cleaning agents tailored to your specific facade material.
Professional facade cleaning in Overijssel and Gelderland
A clean, well-maintained facade contributes to the appearance and value of your property. Removing green deposits is not only a matter of aesthetics but also of preventive maintenance that prevents costly renovations. By choosing the right cleaning method and taking preventive measures, you keep your facade beautiful and in good condition for years.
Are you bothered by green deposits on your facade and do you want advice on the best approach for your specific situation? Contact us for a no-obligation inspection and quote. As a specialist in pointing and facade renovation in Overijssel and Gelderland, we are happy to help you with professional facade cleaning and preventive maintenance. Our experienced employees work with the latest techniques and materials to expertly treat your facade, so you can move forward carefree for years to come.
