The right window connection

1. What are the advantages of prefabricated building elements?

Windows as part of the building envelope are only fully functional if they are installed correctly. Otherwise, moisture penetration and draughts can occur. Especially when the facade is insulated with an external thermal insulation composite system (ETICS in short), working on the installed windows is tricky and time-consuming. This is because the correct connection of the ETICS to the windows is crucial. Partially prefabricated window solutions save time and help to avoid installation and connection errors.

In the automotive industry, it has long been common practice to use prefabricated parts which are assembled together. The modular and prefabricated construction method is also becoming more and more popular in the building industry. Especially when installing an external composite thermal insulation system, time plays a major role, also in connection with weather conditions and scaffolding downtimes. The individual project- and customized serial production enables a continuous high quality. Material consumption and also waste are reduced. Furthermore, prefabricated elements offer more safety through technically perfect connections. For the craftsmen carrying out the work, such elements also reduce the importance of the warranty issue, as processing errors and unsightly construction site solutions are prevented.

2. Why does the installation of ETICS systems in the window areas take (usually) so long?

The installation of an ETICS on the facade surface is part of the daily business for specialized companies. Only the connection details pose a challenge. This is because after the windows have been installed, they have to be covered with insulation material and connected to the surrounding insulation level of the ETICS. In addition, the windows must be waterproofed to prevent thermal bridges, moisture damage and draughts.

Until now, this craftsmanship has been carried out manually on each individual window on the construction site. For a property with a large number of windows, this takes many hours of work. The process is complicated and prone to errors. Visual defects or specific solutions for the construction site are not unusual.

3. How do the planning and the order of prefabricated frames for ETICS work?

A prefabricated window frame (or ETICS prefabricated frame) is a pre-manufactured frame that facilitates the installation of windows in a wall opening and ensures the necessary stability and a secure connection to the building shell. It is suitable for all common windows with frames of wood, aluminium and plastic and is available in a polystyrene or mineral wool version. The insulation boards can be adapted to the rest of the ETICS and the reveal depth of the window opening. In addition, shading elements, such as external venetian blinds and associated external venetian blind boxes can be integrated into the prefabricated frame during the manufacturing process.

Various building components meet in the window area. Connection details to the ETICS, such as window sills, projecting or recessed reveals and lintels, as well as sun protection elements, must be clarified on site at an early stage with the manufacturer's expert advice and the technical parties involved. The window frame is ordered by the craftsman's company based on the previously measured window dimensions, so that the prefabricated frame can be configured accordingly by the manufacturer. ETICS prefabricated frames have a short delivery time so that they can be ordered during the ongoing building process.

4. How does the installation of prefabricated frames for ETICS work?

The installation of the prefabricated frames for ETICS of Saint-Gobain Weber is uncomplicated for professionals.
The assembly occurs in four steps:

• Step 1: After the window installation, the frame element is delivered as a ready-to use window surround and can be transported to the job site by two people.

• Step 2: The frame element is plugged on the installed windows, glued and dowelled in the same way as the insulation boards of the ETICS.

• Step 3: The required frame-seal beads for window connections are already attached to the prefabricated frame all around; the fabric flap of the beads are tightly integrated in the reinforcement layer of the ETICS.

• Step 4: Afterwards the prefabricated frame is covered with the same topcoat render like on the rest of the facade.

If there are control cables for the sun protection, these are routed and connected via an integrated cable box. The prefabricated window frame has a rail to accommodate all standard sun protection systems. This means that shading elements, such as external venetian blinds or vertical awnings can be installed on site without any additional effort.

5. Conclusion: the prefabricated frame as quick and safe solution for a correct window connection

The precisely fitting production of prefabricated frames for ETICS guarantees a perfect connection to the window. Processing errors are hardly possible. The windows are waterproofed all around against draughts and moisture, ensuring perfect heat and cold protection of the building shell. The assembled prefabricated frames only need to be painted or covered with a topcoat render. Handling the elements is simple and takes a fraction of the usual working time. This frees up skilled workmen for other building tasks.

Professional tip

Important: the waterproofing of the floor-to-ceiling windows!

Before the ETICS is installed at the socket part of the facade, floor-to-ceiling windows must be waterproofed with suitable materials. In addition, all windows as well as doors must be waterproofed against the driving rain all around on their external side towards the facade. Thanks to the prefabricated frame the window connection is not only tight at the top and on both sides, but also at the bottom with the window sill.