How does condensation occur on the basement walls and floors of a villa? How to solve condensation water?

The condensation in the basement of a villa is a physical phenomenon where condensation water is generated on the walls and floors, especially during the southern and northern rainy seasons. To prevent condensation, we first need to understand the principle of condensation, and then we can find a scientific and reasonable solution. Regarding the causes of condensation, all we need to remember is the keyword 'dew point temperature'. All our preventive measures are aimed at directly or indirectly reducing the 'dew point temperature'.

1.Dew point temperature

Simply put, dew point temperature is the temperature at which water vapor in the air transforms into liquid water. When the temperature of the basement wall and floor is lower than the dew point temperature, condensation water will be generated, otherwise it will not form. The main factors affecting dew point temperature are temperature and humidity. The higher the temperature and humidity, the higher the dew point temperature, and vice versa. For example, when we take a shower, as the indoor temperature and humidity gradually increase, the dew point temperature will also rise. When the dew point temperature is higher than the surface temperature of the mirror and the wall, we find that fog begins to form on the mirror and condensation begins on the wall tiles. There is also the cold drink bottle that was taken out of the refrigerator just now in summer. Due to the high indoor temperature and humidity, the corresponding dew point temperature is also relatively high. When the cold drink bottle with a lower surface temperature encounters a higher environmental dew point temperature, condensation water will immediately be generated. The above is a simple example of condensation in daily life. Observant friends can pay attention and observe that condensation in the basement of a villa is also caused by the same reason.

Simply put, dew point temperature is the temperature at which water vapor in the air transforms into liquid water. When the temperature of the basement wall and floor is lower than the dew point temperature, condensation water will be generated, otherwise it will not form. The main factors affecting dew point temperature are temperature and humidity. The higher the temperature and humidity, the higher the dew point temperature, and vice versa. For example, when we take a shower, as the indoor temperature and humidity gradually increase, the dew point temperature will also rise. When the dew point temperature is higher than the surface temperature of the mirror and the wall, we find that fog begins to form on the mirror and condensation begins on the wall tiles. There is also the cold drink bottle that was taken out of the refrigerator just now in summer. Due to the high indoor temperature and humidity, the corresponding dew point temperature is also relatively high. When the cold drink bottle with a lower surface temperature encounters a higher environmental dew point temperature, condensation water will immediately be generated. The above is a simple example of condensation in daily life. Observant friends can pay attention and observe that condensation in the basement of a villa is also caused by the same reason.

  Figure 1: Basement Environment Temperature and Humidity 1

The above picture shows a villa located in Yihe Original Works, Haidian District, Beijing. We measured the environmental temperature and humidity during the underground moistureproof and anti condensation construction. From the picture, it can be seen that the wall surface temperature is lower than the dew point temperature, and condensation water has begun to form. This situation is more common in southern regions. During the rainy season, not only in the basement, but even upstairs, the home always appears damp. The walls and floors are often covered with water droplets. After a rainy season, the walls, soft furnishings, sofas, and furniture begin to become damp and moldy, and the home always has a strange smell. In northern regions, basements are also plagued by condensation water during the rainy season. However, sometimes the condensation site is not obvious and often invisible to the naked eye. However, these small droplets of condensation have already invaded the walls, floors, and soft furnishings. Over time, mold and mildew will inevitably appear.

2、 Temperature and humidity

                                                                                                                                                       Table 1: The values in the table represent the dew point temperature of the air at temperature and humidity

Looking back at examples in our daily lives, when we open the doors and windows after showering, the temperature and humidity in the bathroom quickly decrease, and the dew point temperature also drops below the surface temperature of the walls, floors, and mirrors. The mist on the mirror surface and the water droplets on the tile surface also disappear quickly. When the cold drink bottle is first taken out of the refrigerator, the surface of the bottle quickly condenses, but after a period of time, the condensed water slowly disappears. The indoor temperature and humidity have not changed, that is, the dew point temperature has not changed. It is just that the temperature of the bottle body gradually increases over time, and once it exceeds the dew point temperature, condensation disappears.

Having understood the formation mechanism of condensation in water, we have naturally found a technical route for preventing moisture and condensation in basements. So, what should be done and what are the preventive measures for basement condensation? How to treat condensate water? In fact, the key to anti condensation treatment in the basement of a villa is to reduce the relative humidity in the environment and minimize the temperature difference between the walls, floors, and environment. Just like in the two examples above, one is to eliminate condensation by reducing the temperature and humidity in the environment, and the other is to eliminate condensation by increasing the surface temperature of the object.

3、 How to solve the problem of anti condensation?

Reduce the relative humidity in the air. The humidity in the basement of the villa comes from the moisture in the underground soil, which can be completely blocked by the sealing technology of the bottom plate and side walls to completely block the infiltration channels of underground moisture. On the other hand, during the rainy season, the humid air entering the basement through doors, windows, lighting wells, and stairs can be eliminated by dehumidification equipment.

Raise the temperature of the walls and floors to reduce temperature differences. In summer, the temperature of the underground soil on the first and second floors is approximately between 16- 19 ℃, while during the rainy season, the dew point temperature in the basement is generally above 20 ℃. At this point, the low temperature in the underground soil is transmitted to the indoor walls and floors through concrete, forming condensation water. We can build insulation systems on the walls and floors to block heat conduction, reduce the temperature difference between the walls and floors and the environment, and indirectly lower the dew point temperature to eliminate or reduce condensation water.

4、SNTZ-100 aerogel thermal insulation thick medium coating for building is used to prevent condensation in basement.

Application advantages:

(1) Safe and environmentally friendly, eco-friendly, free of volatile harmful compounds, production process and usage are safe, environmentally friendly and non-toxic.

(2) The construction of gel coating is convenient and the comprehensive cost is lower, while the construction process of traditional thermal insulation materials is complex, and the workload is much more than that of gel coating. Air gel coating can be sprayed to effectively reduce construction difficulty, shorten construction period and ensure construction safety.

(3) Sound insulation and noise reduction, long service life. There are infinite gas-solid interfaces in the aerogel, which blocks the transmission of sound waves, consumes sound energy, and has excellent sound insulation effect. The use of aerogel coating on buildings has good functions of sound insulation and noise reduction, moisture and mildew prevention (anti condensation and anti condensation), and its service life can reach ten years.

(4) With thinner thickness and better thermal insulation performance, building gel coating (intermediate coating) can be used together with decorative finish paint, which has multiple functions of thermal insulation and beautiful protection. Besides, the thickness of aerogel coating only needs 2-3mm, which can save more space compared with traditional thermal insulation materials.

(5) Crack resistant self-cleaning, this aerogel coating has a flexible feeling after drying, and has crack resistance, which can avoid cracking or even falling off of insulation materials and external finishes caused by thermal expansion and contraction. Combined with SNTZ-101 aerogel thermal insulation surface coating, it also has good self-cleaning characteristics and reflective heat insulation performance.