The title is misleading as the article primarily focuses on Bulgaria. In contrast, Poland began re-insulating old blocks en masse about 20 years ago, especially in all the larger cities.<p>Moreover, the project isn't as "innovative" as it seems to be portrayed in the article. The quality of these buildings today depends on a variety of factors, such as the precise time they were built (during periods of a strong vs. weak socialist economy), the location (growing worker cities vs. peripheral cities), and their maintenance over the years. During socialist times and even up to today, these buildings were largely maintained by legal "cooperatives." The quality of management within these cooperatives can vary significantly. And management of those basically never changes through the decades.<p>There is also a notable difference in the quality of an average "block" among different Central and Eastern European countries. Having traveled through most of this part of the continent and living in Poland, I've observed that many Balkan Soviet blocks were of significantly lower quality, likely due to smaller economies and greater scarcity of materials at the time, which affected their ability to meet building standards (all these blocks were state-built).<p>For anyone interested in how these were made en masse in months, here's a link to an old Polish movie archive from 1976, which was pretty much the peak of building these in Poland, following a substantial loans from the western world. The video lacks subtitles, but you can still observe the manufacturing, quality control, delivery, and on-site assembly process.<p><a href="https://www.youtube.com/watch?v=NYW5bnD-3Z8" rel="nofollow">https://www.youtube.com/watch?v=NYW5bnD-3Z8</a>