Box windows have design-related sound insulation

Box windows are popular with many people because of their soundproofing properties. Completely closed, the air between the panes absorbs the pervasive sounds. With the casements open on the inside the sound insulation is reduced, but the outside temperature and the light are getting more weight.

Two discs in a wall composite

Box windows have anticipated the principle of double glazing on windows long before the production of double and triple glazed windows. The exploitation of a cavity between two panes has provided the windows in old buildings with an increased sound insulation, which could not be achieved with conventional single windows.

Of course, the general sound insulation function depends on the overall construction. Even though the two casement windows often increase the soundproofing class of the window, the frames and seals must also reduce the noise penetration.

Sound bridges and membrane

If a box window is professionally installed, the composite of the frame with the soffit must be sufficiently sealed and filled. In many old buildings, this gap is the cause of the largest sound transmission, which can be amplified by the transmission of sound waves on the window frame.

The frame of the box window must be mounted in such a way that it can not form a membrane that could absorb incident sound waves. The sill must also be mounted vibration-free, so that it does not act as a sound bridge to the window frame. Often, insulating the window reveal from the inside increases the sound insulation.

Profiles and glazing

How strongly the sound is prevented by a box window depends on the profiles of the window seal. If the inner window has a stepped milled wooden profile, the frame looks like a continuous solid wood against incident sound.

Normally, a modern wood profile on the inner window is sufficient to retrofit a box window to a soundproof window. The increase in sound insulation can be additionally supported by insulating glass or the application of soundproofing foil.

Tips & Tricks

If you are offered particularly thick window glass types, this refers in most cases to the energy values. For example, for self-insulating glazing, check whether sound insulation is also supported.

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