What is important in this topic is what is meant by the terms building dehumidifier and/or dehumidifier, as building dehumidifiers are also wrongly referred to as heaters (oil, gas or electric) and fans. By dehumidifiers/extractors we mean – those devices, which extract moisture from the air according to the refrigeration heat pump principle.
Dehumidifiers/building dehumidifiers without, or in combination with, fans
In short, it can be said that dehumidifiers/building dryers alone or in combination with fans do not damage fresh building materials provided that the building work is carried out in the same way as on a warm dry summer day.
What do we mean by this?
Everyone who works in construction knows that on hot dry days measures must be taken to prevent fresh floors and fresh plaster from drying too quickly. This can be prevented by moistening walls with water, covering floors with plastic sheeting and preventing excessive ventilation with dry outside air. On a cold and rainy day in winter, this is sometimes forgotten and building dryers, fans and heaters are used in this critical period without humidifying walls and/or covering floors.
Why are these measures being taken and for how long?
Chape, anhydrite and plaster must quietly bind the added water to themselves (to the crystals) in order to reach their strength. In the case of screed floors, the period during which forced drying may not take place is 7 days. In the case of anhydrite floors and plaster, a period of 24 to 48 hours applies, depending on the manufacturer’s instructions. If you observe these periods, a dehumidifier/building dehumidifier with or without fans will not cause damage to your building materials.
Dehumidifiers/building dehumidifiers without, or in combination with, fans and heaters
If dehumidifiers/building dryers are used in combination with heaters, the story changes, especially if heaters are used improperly.
Fresh floors bind sufficient water within 7 days (screeds) or 24 to 48 hours (poured floors). This water cannot be extracted from the floor by dehumidifiers/ construction dryers after this period. Moisture on fresh floors under 30 days old can still be extracted from floors at too high temperatures (above 35°C) due to incorrect stove or stove application. These include single-walled electric heaters (see blog) and warm air transport layers directly on the floor. In these cases, the floor may become dusty and coatings and adhesives may fail to adhere in places.
Cracks can also be caused by large temperature differences in a floor, which in turn creates tension in the floor.
Damages caused by?
Many damages in the building industry are caused by the use of heaters and never by dehumidifiers/ drying units, if the 24/48 hours and 7 days rule (depending on the material) is applied.
Dryfast provides highly educationaltraining courses in the field of dehumidification, please contact us on: 010-4261410 or send an email to: firstname.lastname@example.org