Existing methods of mold control

Mold is a significant problem and everyone fights it in their own way. It is important to know that mold affects our health, with children, people over 60, and those suffering from lung and respiratory diseases being at the highest risk. In this article, we will examine all existing options for combating humidity and mold, and provide our assessment of the effectiveness of each method.

For the average person, mold is simply black spots on walls, ceilings, and bathrooms. However, as a specialist, it is crucial for me to detect hidden mold that cannot be seen by the naked eye and poses the greatest danger to residents' health.

Hidden mold is the type that is not visible on the surface but can actively grow in hard-to-reach places inside buildings (behind drywall, under wallpaper or paint, inside ventilation systems, behind furniture or inside built-in cabinets, under floors, and carpets).

A significant number of apartments and houses we inspect have completely white and dry-feeling walls, but they conceal black mold. Signs of mold may include a musty smell or small black spots around shower stalls or windows.

This is an important point because many are unaware of the presence of mold in their homes. Now, let's move on to analyzing all the existing methods of mold control.

1. Mechanical Removal

- Scrapers and brushes: Using stiff brushes or scrapers to remove mold from surfaces, especially on hard materials like tile or concrete.

Fact: These tools are effective for removing visible mold spots on hard surfaces like tile, concrete, and metal. Stiff brushes physically remove mold from the surface, which is especially useful for non-porous materials.

However, scrapers and brushes can only remove SURFACE mold. They do not eliminate mold spores that penetrate deep into porous materials (such as wood, plaster) or remain airborne.

In my practice, I've seen a large number of properties with hidden mold located under the plaster, which is invisible to the eye.

2. Chemical Agents

- Chlorine bleach (any store-bought mold removal product that can be purchased without a license).

Effective against surface mold but may discolor or damage some materials. It should be used with caution in well-ventilated areas.

Fact: This is the cheapest, most dangerous, and least effective method. Frequent reapplication is often required, and deep spores do not disappear. Furthermore, washing walls increases their moisture content, promoting even more hidden mold growth inside the wall. Additionally, bleach destroys brick walls, one of the most popular construction materials.

Moreover, chlorine bleach releases fumes containing chlorine. Inhaling these fumes is harmful to health, especially in poorly ventilated spaces (almost all homes I inspect have inadequate ventilation systems, which should be calculated properly).

The first two methods are not viable options for us.

3. Drying – Using dehumidifiers, fans, and air conditioners to reduce humidity levels in the room.

Perhaps the most popular method used by the majority of people is air conditioners or household dehumidifiers.

To understand, let's examine how they work. The task of dehumidifiers is to lower the humidity of the air to normal levels. A dehumidifier is indeed effective in a bathroom after a shower or in a room where clothes are drying.

Many users note that the room feels more comfortable when the dehumidifier is running, but once turned off, the humidity returns to its previous levels within an hour.

Does a household dehumidifier affect mold? To answer this, we need to understand the conditions under which mold forms. Mold requires two conditions: liquid water and a nutrient medium (plaster, drywall, water-based paints, wood, etc.). Temperature doesn't play a significant role, as mold can grow even in freezers.

The capacity and characteristics of household dehumidifiers are insufficient to dry building structures (walls, ceilings, floors). Therefore, this method does not work for combating mold.

The moisture content of a wall cannot be determined by touch; this is done using special equipment.

Our company has professional wall drying equipment, which can only be used by licensed engineers. But even this is not the full solution because fighting mold always requires a comprehensive approach. If you dry the walls but do not eliminate the causes of dampness, the problem will return.

4. Ventilation – Many who have studied the topic of dampness and mold at least a little understand that it is essential in the fight against mold and dampness. My practice shows that in almost all properties, the ventilation system is either absent, insufficient, or incorrectly set up. Ventilation through windows is not considered proper ventilation.

The purpose of a well-functioning ventilation system is not only to bring fresh, clean air but also to prevent mold growth and normalize humidity levels throughout the room (unlike household dehumidifiers).

However, ventilation plays more of a supporting role, as it won't reduce the moisture in damp walls, lower the dew point, or fix leaks. Ventilation is a must-have, but only as part of a comprehensive, properly selected, calculated, and tuned solution.

5. Wall Insulation – It increases the temperature of the building envelope, but with the wrong choice of insulation or technology, it can lead to significant wall, ceiling, and floor moisture, greatly increasing mold formation and growth. This strategy should only be used in conjunction with properly adjusted ventilation; otherwise, the mold problem may worsen.

Since the early 2000s, significant changes have been made to construction standards in Portugal concerning building insulation. As a result, urban apartment buildings and other new constructions must comply with new energy efficiency standards.

The main changes involved the introduction of external facade insulation systems, which help retain heat in buildings during the winter and prevent overheating in the summer.

6. Waterproofing – Professional measures to seal walls, floors, and ceilings to prevent moisture penetration.

Most leaks are not caused by broken water supply or sewage pipes, but due to a lack of or poorly executed waterproofing. Water can seep through walls, roofs, and floors in very small amounts, taking months or even years to do so. This type of leakage is the most insidious because water completely saturates the building structure, causing mold to form inside the walls.

Even for a specialist, it is challenging to determine the cause of this type of leak, as specialized equipment is needed to locate the source and pinpoint the exact reason for the moisture.

The success of eliminating dampness and mold depends on accurately diagnosing the issue.

Various waterproofing methods exist, and the appropriate one is chosen based on the identified cause. Often, several methods are applied simultaneously.

7. Heating, Infrared Heaters, Infrared Heated Floors:

We have a moderately warm climate. Winter temperatures rarely drop below 10°C.

This explains why homes here are built for summer coolness rather than winter warmth, and why portable heaters are more common than central heating systems.

Regular heating helps maintain a comfortable indoor temperature, which can reduce condensation on walls and surfaces.

However, this only happens when there is a significant temperature difference between the inside and outside of the house (over 20°C). In countries with prolonged heating seasons and sub-zero winter temperatures, heating reduces indoor humidity.

In Portugal, in cold homes without insulation and with poorly sealed building envelopes, heating can raise the temperature to a comfortable level, but it will be very expensive and will not affect mold.

If the house is insulated, dry, and airtight, it will maintain a comfortable temperature year-round without the need for heating.

8. Antifungal Primers and Paints – Special compounds for protecting walls and ceilings from mold.

These should be used after completely ridding the house of mold, when the old finish has been completely removed and before new renovation work begins.

9. Home Restoration After Mold – This is the most expensive procedure of all mentioned.

If your home is affected by hidden or visible mold in most living areas, it is necessary to dismantle and dispose of all porous building materials (drywall, wood, ceiling panels, plaster, etc.). You will also need to dismantle and dispose of all utility systems (sewage, air ducts, air conditioners – everything except steel ducts, which are the only ones that can be mechanically cleaned).

After dismantling, all rooms must be treated with special chemicals – only a licensed company specializing in mold remediation (not to be confused with cleaning companies) can do this.

In conclusion, accurate diagnosis and identifying the causes of dampness and mold are crucial to the effectiveness and cost of the work. In our practice, we often encounter clients who spend enormous amounts of money on renovations, only to see all the problems with mold and peeling paint return.

Conversely, proper diagnosis can save you money on repairs, ensuring that you won't need to redo the work, and allowing you to select a solution that fits your budget (ranging from affordable options to full mold remediation).