A new type of airtightness seal: spray-on or brush-on liquid film from pro clima

This innovative product impresses with its wide range of possible applications

Spraying instead of sticking: AEROSANA VISCON can be used to create a new type of vapour retarder and airtightness seal.

Who says that airtightness films always have to come as sheeting in roll form? With AEROSANA VISCON, there is now a liquid vapour retarder and airtightness layer than can be sprayed directly onto surfaces to be sealed. When it dries out, the acrylic dispersion turns into a durable, seamless elastic protective layer. Suitable subsurfaces include non-plastered masonry, porous panel-form materials and membranes too. With its humidity-variable sd value, AEROSANA VISCON is suitable for interior air sealing and also for protected outdoor areas. The spray film is water-based and has achieved excellent values in the hazardous substance test. Continue reading

Flank diffusion – what it is and how to prevent it

pro clima clients ask – pro clima engineers answer

Airtightness is good, but it is not everything: there is also the matter of diffusion! When we speak of diffusion in civil engineering, we are referring to the gradual transport of moisture through a building component. This transport is driven by the pressure difference between the interior and exterior. As water molecules always want to move from warm environments into the cold, diffusion normally occurs from the inside to the outside in wintertime. A vapour retarder hinders the transport of these molecules.

Unforeseen: Entry of moisture through adjacent components

For example, if an interior wall penetrates through an insulation layer (the vapour retarder is cleanly attached to the wall on the left and right, i.e. everything is airtight), so-called flank diffusion can occur. The water vapour looks for the path of least resistance – which in this case is the interior wall. In the case of structures that are open to diffusion on the outside, this may represent a manageable risk. However, if the structure is impermeable to diffusion on the outside, moisture problems can soon occur. After all, there is a fundamental problem here. The interior wall has a large surface area, so it absorbs a lot of moisture, but there is only a smaller area available for drying to the inside – i.e. the wall cap.

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