How to determine the dew point and what it is: definition, calculation and elimination
Most of us have heard of this concept, as a dew point. In this article we will consider what it is and why this physical factor must be taken into account when carrying out insulation work on the house. Dew point is the distance from the ground, where the air, cooled to a certain temperature, forms dew. This figure depends on several factors. The key is the air pressure inside the building and on the street.
It is not always possible to simply determine this indicator. But notice, that every building owner must determine, which is the dew point in the premises of his house, as it affects the comfort of living.
If the dew point in the room is too high, in this case the main building materials - concrete, metal and wood - will not provide the desired effect when building a house, and their service life will be short. Here you will need a high plinth, or additional protection against moisture.
If the interior of the building is made of polymer flooring, then ingress of condensate material into the structure such defects may occur during the operation of the floor covering:
- bloating;
- exfoliation;
- shagreen.
It is impossible to determine this figure in a purely visual way. To do this, you must use a special device called a non-contact thermometer. In addition, you should use the table, in which a special section is described, how to determine this parameter in the walls of the building and make its correct calculation.
What is the dew point in construction?
This term should be understood as an indicator, which determines the level of humidity in the air. That is, you can talk about it, that the higher the humidity level in the room, the higher the dew point. However, two other important criteria need to be taken into account when determining this indicator:
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variable pressure indicators;
- outside air temperature.
About that, measured dew point in degrees, not everyone knows. In the end it turns out, what dew point - the air temperature of a certain value, in which it itself is saturated with moisture vapor. However, that fact must be taken into account, that the point itself cannot be higher than the air temperature.
It is necessary to remember, how condensate occurs: it is formed when warm air collides with a cold surface. To make it clear to everyone, how this indicator works in real conditions, it would be correct to consider the occurrence of such a phenomenon, like fog. It is necessary for its appearance, so that the outside air temperature and the dew point temperature coincide with each other. In other words, taking into account these indicators, you can accurately determine the level of humidity outdoors and indoors.
What factors affect the dew point?
On such an indicator, as the dew point is influenced by several factors:
- One of the main - the thickness of the walls of the room. Another equally important is what materials are used to insulate the walls of the building. Temperature is also significant. It may vary depending on the location of the structure. The temperature coefficient in the northern territories will differ from the regions, located in the south.
- Another important factor is humidity. If the air contains moisture, then the more of it, the higher the dew point.
That there was an accurate idea of it, what is the dew point and what effect can be influenced by various factors, consider this factor with examples:
- Uninsulated wall indoors. In this case, the dew point will move. This will happen under the influence of weather conditions outdoors. If the weather outside is stable and there are no sharp fluctuations in temperature, then the dew point will be located as close as possible to the outer wall. In this case, the negative impact on the premises will not be provided. In that case, if there is a sharp cold snap, then there will be a gradual movement of the dew point in the inner part of the wall. And that can lead to that, that the room will be saturated with condensate, resulting in slow wetting of wall surfaces.
- Wall, having insulation on the outside. The dew point here will be located inside the wall in the insulating layer. Choosing a material for insulation of structures, it is necessary to pay attention to this factor and to approach correctly calculation of thickness of heat-insulating material.
- Wall, insulated inside. Here the dew point is located between the insulation and the center of the wall. This option is not the best, because if the outdoor air is dominated by high humidity, then at sharp cooling there will be a movement of a dew point on a joint between a heater and a wall. And this can have the most negative impact on the wall. The owner can resort to internal insulation of structures only then, if there is an efficient heating system inside the house, which is able to provide the same temperature in each of the rooms of the house.
In that case, if the weather conditions are not taken into account when carrying out repair work in the house, then it is almost impossible to solve the problem. The only right decision is to remove everything, that was done, and then do all the work again, but already correct given the dew point. However, this will lead to high costs for building owners.
Determination of dew point and calculation
Man, living in the house, in which high humidity prevails indoors, faces big problems. Condensation can lead to health problems. High risk of getting this disease, like asthma. In addition, condensate adversely affects the structures of the building, reducing their service life.
If the level of humidity inside the house is high, then mold forms on the walls and ceiling, which is hard to get rid of. In such cases it is necessary to take cardinal measures - to replace the wall and ceiling surface. This is the only way to get rid of harmful microorganisms.
To avoid these unpleasant moments, it is necessary to calculate the dew point in advance. So, you can find out, whether it makes sense to carry out repair work in a particular house, to insulate walls.
It is worth saying, what each building has its own individual dew point. And that means, that work on its calculation will be carried out with certain differences.
Before you start calculating this parameter, the following factors must be taken into account:
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climatic conditions in a particular region;
- the thickness of the walls of the building;
- material, from which they are made;
- the presence of strong winds.
During construction, the developer must monitor, that in the materials used at construction humidity did not increase and the dew point was not formed. Only a specialist can properly enable dew point sampling. If the dew point in the house will be high, then the specialist will make a conclusion, that the insulation of the building was done incorrectly.
This answer can be considered partially correct, as at the correct warming there is a dew point movement, as a result, this figure changes. in addition, repair work performed on the technology affects the appearance of condensate on the walls.
Instructions for determining the dew point on the table
In order to correctly calculate the dew point, you must have in addition to the table and special equipment.
Tools for determination
To correctly determine the dew point, the following tools will be required during the work:
- thermometer;
- hygrometer;
- contactless thermometer.
Stages of calculation
Indoors, in which the dew point is measured, it is necessary to measure the surface from the floor 60 cm and place the thermometer at this height. It can be placed on the table surface. Next, use a thermometer to measure the air temperature. Then you should use a hygrometer and measure the humidity in the room. Focusing on the values in the table, you can determine the dew point.
After that it remains to find out, whether it is possible to carry out work in such a room. Example, owner plans to insulate the room or arrange polymer floors in it. To find out, whether there is a sense in carrying out such works, resort to the use of a special non-contact thermometer. To do this, again measure the distance from the floor 60 cm, then measure the surface temperature. If you do not have a non-contact thermometer, then in this case it is necessary to take an ordinary thermometer and wrap it with a cloth. After 15 minutes it is necessary to take readings.
At the final stage it is necessary to compare two results. If the surface temperature differs from a certain dew point by 4 degrees, it says so, that the room is dominated by high humidity and there is a high dew point. In this case, insulation work should be carried out under the supervision of a specialist. Before starting, the thickness of the material must be calculated, which will be optimal for quality insulation.
How to solve the problem with the dew point?
There are several possible places on the walls of the building, where a dew point may appear:
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In the outer surface of the wall. Here the probability of this parameter is minimal. Dry, usually, the inner wall remains.
- Closer to the inner surface of the wall. There is a high risk of condensation in the situation, when it gets cold outside.
- On the inner wall of the building. Dew point appears here in rare cases. If it occurs, then no measures you have taken will help get rid of it. It remains only to reconcile, that the walls will be slightly damp during the winter.
In such cases, to solve the problem, you can add vapor barrier to the wall surface. This will ensure the retention of water vapor, and it will not pass through the walls into the room. And this will eliminate the dew point on the wall surface and ceiling surface.
conclusion
Dew point is an important indicator, which many developers do not pay attention to during construction. Namely, the service life of building structures depends on it. If this parameter is not taken into account, then the walls will be wet during operation, which can lead to the development of decay processes in the structure. Mold forms on the walls, and this can adversely affect human health.
When warming the walls, then this parameter must be taken into account. Only in this case it is possible to carry out high-quality thermal insulation of structures. To determine this parameter, if the building owner has no experience in this matter, it is better to involve a qualified specialist. He will not only be able to correctly calculate this parameter in the building, but also give recommendations, which will help you to perform quality repairs and avoid high humidity in the house.
