Apply a window sealing tape

Older builders in particular still insist on the outdated technology when installing windows, in which only construction foam is placed between the window reveal and window frame. This does not correspond to the current state of construction technology. Instead, a window sealing tape should be attached.

Structure of the window connection joint

First of all, when it comes to installing windows today, the inside is always tighter than the outside. This means that the connection joint between the window and the window reveal must be airtight on the inside. In most cases, the joint should be open to diffusion towards the outside so that moisture can escape from the building fabric. This is guaranteed today after the following implementation (from the inside out):

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  • Butt joint with silicone or acrylic
  • possibly construction foam (between silicone joint and window sealing tape)
  • Plastering strips or sealing tape on the circumferential outside of the window frame
  • possibly construction foam
  • Window sealing tape on the outside
  • Delusion

Window installation according to RAL

This largely corresponds to the window and door assembly according to RAL. It should be noted that the RAL guideline does not specify any special work steps or materials. Rather, it describes which tightness state must be achieved and how this can be implemented.

Apply the window sealing tape

First of all, the window reveal must be prepared. This must be smoothed out absolutely. Then the window sealing tape or. the plastering strips are glued to the window frame according to the manufacturer's instructions. Now the window can be fixed and installed. The dowel-free window screws are now also installed for this purpose.

The sealing tape is now followed by PU foam from the inside and outside. This foaming should not be confused with the previously common window installation with construction foam. Another window sealing tape can now be pulled in on the outside. The sealing tape can also be used indoors. However, due to the high costs, an air and gas-tight silicone joint is always drawn instead.

Silicone is fine, but then a construction joint

This possibility exists in principle. However, you should definitely keep in mind that a silicone joint is a construction joint that must be renewed at regular intervals. A veneer is applied from the outside following the window sealing tape. Depending on how the window sill is now installed, it still has to be sealed.

Tips & Tricks Inside, silicone or acrylic can be used. But this is due to the properties of the joint. Silicone is elastic (flexible), but it cannot be painted. Acrylic is not elastic, but can be painted. In bathrooms, therefore, acrylic is often used all around on the right, left and above, and silicone on the underside for sealing.