AlĂ´ Giovanni,
yes, you are right.
There was a fire which was - according to the most current information - has been caused by welding operations carried out on the structure of the main roof.
As to my best knowledge, the welding must have caused a superheating of the insulation layer between the roof's surface and the inner building's ceiling linings. Although there are still current determinations in regard to the fire's cause at present, the fire brigade experts do suppose strongly that even that was the reason. All in all it appears to be judged as careless fire-raising!
However, I have just visited the TV-News a few minutes back and the damage upon the building is not as hard as originally assumed. The responsible persons even suppose to use the building for public concerts again already in the beginning of June(!). This appears possible, amongst others, since not that much of extinguishing water has leaked through.
Nonetheless, they have to rebuild the entire roof now, which will most likely cost a few million Euros. But it could have been much worse. Thanks God no one was injured and - what was luck as well - I have seen an interview with a few members of the Berlin Philharmonic Orchestra, who have entered the building while the fire brigade has fought the fire(!) to rescue the musical instruments of all those colleagues which were not present and who had left their instruments within the building while themselves were absent!
As they said in the interview, the instruments were priceless and irrecoverably due to their old age.
Thank you Giovanni for considering the Berlin Philharmonic Orchestra as being "the best" in the world!
I truly guess that they are really one of the best in the world...
And by mentioning Herbert von Karajan. I guess there is a reason for that the Berlin Philharmonic Hall is called "Zirkus Karajani" which might be translated with "Circus Karajani" :-)
Best regards to Sao Paulo,
Stephan
P.S. I'll attach some pictures for you...