When someone decides to install new aluminum frames in their home, I believe they are unaware of what closed aluminum sashes are. A common “mistake” in aluminum constructions, specifically in casement windows, is the use of sashes without glazing beads (closed sashes). Let us clarify that this does not concern sliding aluminum frames. Closed sashes are the reason why frames sag – hit (casement sashes) or catch when opening, preventing them from locking.
What are closed aluminum sashes?
We call sashes that do not have glazing beads on the inside of the frame “closed”. In casement aluminum frames, with closed sashes, the proper glazing of the panes is impossible (which is why the sashes sag – hit and do not lock). As a result, the casement sash begins to “catch” (deform) within a short period (even one year). Furthermore, it does not operate correctly (opening – closing), and it starts to experience losses (air – water) because the gaskets do not seal properly. These specific sashes, however, are unsuitable for frame construction.
Why are closed sashes manufactured?
Closed aluminum sashes require much less time in the construction of a frame. This means that the manufacturer reduces production costs. Many manufacturers, in an effort to make their products more competitive, construct aluminum frames with closed sashes.
Sash Profiles with Glazing Beads
As you can see in the image, the glazing bead allows us to properly glaze the glass and avoid the negative consequences of a closed sash (frames creak – frames catch).
Photo of a closed glass sash.
As you can observe, in a closed sash, glazing is not possible. There is no necessary gap for it to occur. The owner of a frame with a closed sash will soon face unpleasant consequences. Improper glazing is the reason why frames creak (casement) or catch when opening.
Photo of a casement glass sash with glazing beads.
Aluminum frames with glazing beads can be glazed (spacers can be placed between the glass and the aluminum). The manufacturer can raise or lower the glass depending on the specific case. If a sash catches, a spacer can be added at the bottom to raise it, etc. This cannot happen with a closed sash and constitutes a difficult-to-solve problem. Improper glazing is the reason why frames creak (casement) or catch when opening.
Is silicone between glass and aluminum contraindicated?
You should also be very careful when aluminum frames are installed. Many manufacturers do not install a gasket on the exterior side (between glass and aluminum) but rather silicone. This method is contraindicated by all aluminum frame companies (Europa, Etem, etc.).
