Pressure drying and dehumidification of layered constructions

  • Pressure drying is one of the most effective and fastest commercially available methods for drying layered structures. Pressure drying can be used to advantage for drying floors on concrete slabs, where the water has leaked down into the fill or insulation under the floating floor. Corroventa has a number of products that are used for drying layered constructions such as walls, ceilings and floating floors. From flexible system solutions with dehumidifiers and turbines to the patented Combi series that offers the possibility of both pressure and suction drying in the same machine.

    Pressure drying, an unbeatably effective method for drying

    The technique is based on the dried air being led into a turbine, which raises the temperature and pressure of the air. The dry and very warm air is then forced down into the building construction via a hose system, which is connected to holes that are drilled in the construction. The warm, dry air is forced through the wet construction, where the heat increases the vapour pressure in the damp material several times over and, in this way, increases the drying rate. The damp air is returned to the room via natural openings, or holes drilled in the construction, where it is once again sucked into the dehumidifier and dried anew before it is forced back into the building construction. The drying time can be reduced significantly by protecting the drying process from exposure to damp air coming from the surroundings. This can be done quite simply by closing valves and sealing other openings into the room where the drying process is underway. However, wherever possible the plastic enclosure method should be used.

    The great advantage of creating a closed system is that a very limited quantity of air is dried and heated and the dehumidification is then concentrated on the water damage in the construction. In this way, a very quick and energy-efficient drying process is obtained.

  • Heat is an effective driving force

    To shorten the drying time, the temperature of the air used for drying can be increased. The warmer the material to be dried is, the more efficient and quicker the drying process will be, as the vapour pressure in the wet material increases. An increase as small at 10°C can halve the drying time* in some cases.

    *Because the drying rate is directly proportional to the difference in vapour pressure, this means that drying at 30°C 20%rh is theoretically twice as fast compared to 20°C 20%rh.

  • Important to consider before pressure drying

    A layered floor construction should always be sucked free of water prior to starting pressure drying; read more about this under suction drying. It is important to bear in mind that the dry, warm air also affects all wooden material in the room where the drying process is being carried out. For this reason, care should be taken to remove or carefully wrap in plastic all furnishings that could be damaged. If possible, plastic enclosure can be used, to limit the area to be dehumidified, and in this way protect surrounding material. A hygrostat can be used to advantage, to control the humidity during the drying process.

    Picture: Combi machine. Dehumidifier and turbine in the same unit designed for effective pressure and suction drying.

  • A combi machine for pressure and suction drying

    When pressure drying, it can be an advantage to use a combi machine comprising dehumidifier and turbine in the same unit. The extremely low noise level also makes it suitable for use in residential spaces.

  • Hose system for easy installation during pressure and suction drying

    Corroventa’s C16 and C25 hose systems can be used to transport air while suction or pressure drying. The hose system is modular and includes junctions, hoses and pipe bends and T-connections with rubber seals. The system, which has CAMLOC couplings, makes an installation simple, quiet and reliable. Several hose systems can be coupled together to dry larger areas, or both of the hose systems can be combined to dry a layered floor and a wall simultaneously.

    Picture: Dehumidifier and turbine pressure drying a layered floor and a stud wall simultaneously.

Products that can be used for pressure drying