Professionally plaster windows

Especially the renewal of windows is up to date like hardly ever before. High energy prices, as well as high demands on the Energy Saving Ordinance and thermal insulation, whose insulation values ​​of a facade insulation barely after, are the main reasons to renew windows. Exactly for these reasons but also the plastering of the windows is given a special meaning. Afterwards you will receive the necessary information.

Connection between window and facade

Renewing windows is largely determined by the thermal insulation of new windows. But to understand why the plaster around the window is so important, first the complete window structure must be understood, which we subsequently explain from the inside out.

  • Composite insulating window (multiple glazing in the composite frame)
  • Window wing in which the composite window is airtight
  • Window frame in which the wing sits airtight
  • Window reveal with which the frame is bolted without thermal bridges (no anchor clamps with dowels)
  • Repainting around the windows on masonry and soffit

RAL-window installation

One word that keeps falling is "airtight". Equally important is the removal of thermal bridges. Therefore, RAL quality guidelines (RAL window and door assembly) should be strictly followed.

The changes from the previously applied standard are obvious.

  • Between the frame and the soffit (outwards as well as inwards) a compact sealing strip instead of PU foam)
  • Window fixing screws without dowels (forming thermal bridges)
  • inside non-permeable film inside under the plaster
  • outside diffusion-open film to the outside under the plaster

Pu foam

Some craftsmen still use PU foam for caulking and even refer to the RAL guidelines. Although these guidelines do not specify a concrete procedure, polyurethane foam is no longer used because the other properties of the construction foam do not lead to an airtight space between the frame and the soffit. This would create a thermal bridge again.

Connection joint inside with acrylic or silicone

The same applies to the connection joint on the window frame. After RAL, clearly a compriband should be used. These precompressed sealing tapes, however, are very expensive. In terms of cost-effectiveness, therefore, some companies that are quite RAL-mount refer to the use of silicone or acrylic.

Considering the economic efficiency as the decisive factor, the application is quite acceptable. But: forget you do not ask that acrylic or silicone joints are maintenance joints, so need to be renewed regularly. Otherwise, a thermal bridge is created here.

Cleaning edges and sealing foils

Instead of Kompribandes then often plaster finishing strips and sealing films are applied under the plaster. This approach is also justifiable. As far as the tightness of your window is concerned, you should always follow a rule of thumb: from outside to inside, a window becomes ever denser.

Sealing foil under the plaster inside

This special sealing foil, which you install in the interior of the window, must not be vapor permeable. It is mounted in front of the 10 degree border (below which condensate is created) of the facade. Then comes the plaster. The moisture in the room must not penetrate the masonry or the connecting joint here. If the film were behind this 10-degree boundary, the water vapor that had penetrated up to it would condense, and mold would be a consequence.

Sealing film under the plaster on the outside

About this special film, the window is then plastered conventional. But the outside of the window must be protected accordingly. Only moisture contained in the masonry must be able to escape to the outside. So an outwardly permeable film is incorporated under the plaster. Otherwise, the requirements are the same for existing buildings and old buildings: the window must be rain- and impact-resistant. If this film is applied, you can also plaster the window from the outside.

Tips & Tricks

It can be seen that window assembly today is very demanding and requires a lot of specialized knowledge. That sounds really complicated at first. However, those who are adept in their technical and technical skills quickly understand the logical structure of a window seal. If you still have questions about this: Under window and door assembly according to RAL you will receive all necessary information and explanations.

Video Board: How To Install A Window (New Construction)