Mold
Mold in the form of spots on the walls should cause understandable concern, as this “guest” can be dangerous to your health.
Mold on the walls is caused by excessive humidity, which condenses on the walls. The most common cause of high humidity is poor ventilation. Another reason may be problematic plumbing. In particular, such untidiness is not uncommon in apartment buildings, where neighbors flood their apartments. As a result, ideal conditions are created for the development of fungus and mold. Also, the cause of dampness on the walls may be faulty insulation of the house. In this case, you will need the help of professionals.
Poorly installed window frames can also lead to mold. Sometimes it is quite difficult to determine the causes of increased humidity. Many people eliminate superficial phenomena in the hope that mold will not appear again. However, if the cause is not eliminated, mold will definitely "visit" your home again.

Harmful mold
Mold and fungus has the most negative impact on human health. Because of it, we can feel frequent headaches and fatigue. Mold can irritate the mucous membrane, cause allergies and respiratory diseases. Therefore, if you see the slightest signs of mold in the house, make every effort to get rid of it.
Methods of struggle
It all depends on the degree of moisture penetration into the wall. Usually mold occurs in the corners of walls, areas where walls and floors meet, and at window frames. Often the reason is that the walls are too "cold". If the wall is covered with wallpaper, it must be removed and the wall itself washed with detergent and water. Then the wall is covered with a fungicide.
Sometimes mold and fungus occur in bathrooms where there are no windows. The control scheme in this case is similar. The walls should be washed with water and covered with a fungicide. After drying, the walls can be painted again.
If the plaster is falling off the wall, it means that mold penetrated very deeply. Remove the entire layer of affected plaster, fill the voids with a solution, having previously treated them with a fungicide, and only then plaster the walls again.
When removing mold, remember that fungicides are poisonous and must be used strictly according to the instructions that accompany the product. If, despite all efforts, the problem returns, it is necessary to resort to the services of a company that specializes in mold removal.