Revisions log for Answer #1072
This is the answer to the question Why is every word coming through the windows? Is the insulation broken?
Revision 1
If by "construction joints" you mean the gap between the window element and the wall, and if that gap is that large, I'm not surprised. Foam alone won't keep sound out, you need protective strips on top. For single leaf windows, the difference between the outer size of the frame and the opening is usually about 3 cm (total, mind you: 1.5 cm per side), for larger formats it can be 2 cm per side. Someone must have taken measurements (or ordered the windows before the wall openings were finished and measured from the plan with thick caution) and then installed window elements that turned out to be too small. With any luck, joining profiles from the same frame profile system would work to adjust the difference. This sounds like a typical case of the "foam cures all excessive tolerances" attitude.
Once again, let's be clear: the full perimeter gap alone is sufficient for this phenomenon, the glazing and sash can be installed correctly.