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Window and door connections

Professional waterproofing technology

Window and door connections

The expert sealing of the building envelope, especially of the connection joints between window resp. window element and building structure, is of paramount importance. Reliable protection from environmental conditions like rain, moisture, wind and air pollutants as well as minimum heat loss can only be achieved if the right materials are used and if they are properly joined using the right method of application. Only then can the value of the property be maintained and a long useful life be guaranteed.

Making the building shell air-, wind- and waterproof as well as preventing mold growth are structural-physical requirements of highest importance and have been stipulated by the German Energy Saving Ordinance (Energieeinsparverordnung EnEV) and DIN 4108. Following the laws of building physics, water vapor always seeks equilibrium. Therefore high humidity will always move to an area with lower humidity until a vapor pressure equilibrium is established. When moving through walls and ceilings, as a rule from the in- to the outside, water vapor always takes the path of least resistance.

In the window area, many different building materials come into direct contact with each other. Proper sealing of the joints is therefore of utmost importance. Sealants, pre-compressed foam tapes and window connection strips are able to absorb movement between the different materials of walls and windows. Please note that connection joints need to be watertight and soundproof. Following the principle "Inside tighter than outside", the RAL "Guideline on the planning and installation of windows and front doors" requires a higher vapor impermeability (sd-value) for internal sealing. Airtight sealing around the perimeter of the window on the room-facing side is not sufficient to prevent structural damage caused by condensate.

TEROSON stands for the quality installation of windows and facades. Basically, there are two different design options for windows: either individual elements (so-called punched window facades) or long rows of windows set side by side (so-called strip window facades). Whether punched or strip window facade: the elements need to be expertly installed and sealed. In new builds, this is mostly done with the help of plasterable window connection strips or pre-compressed foam tapes. When renovating existing buildings, external window sealing is mostly done with gun-applied sealants or also with pre-compressed foam tapes. In refurbishment projects, sealing and insulation work is normally done with high-quality PU foams. For the inner sealing level, often gun-applied sealants or connection profiles are used that have been tested and approved for this purpose.

The decision on which products to use strongly depends on the structural conditions on site, the type of facade construction and the requirements to be met by the building component/window element. Another important factor to consider is whether the window is installed in a new build or whether an old window is replaced in an existing building.

Nowadays, expert sealing is carried out based on the so-called 3-level sealing model (inner, medium and outer sealing level).

3-level sealing model

1st level: The inner area of the joint must be airtight towards the living space, thus separating the indoor from the outdoor climate. In this area, the temperature must always be above the critical temperature for mold growth (13-degree isotherm).

2nd level: The center part of the joint is the area of thermal and acoustic insulation.

3rd level: On the outside, the joint must be protected from driving rain, wind and UV light. Water that penetrated from outside must be controlled and directly drained to the outside. At the same time, moisture must be allowed to escape from the functional area to the outside.

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