EASA 145.A.25....
Facilities are provided appropriate for all planned work, ensuring in particular, protection from the weather elements. Protection from the weather elements relates to the normal prevailing local weather elements that are expected throughout any twelve month period. Aircraft hangar and component workshop structures should prevent the ingress of rain, hail, ice, snow, wind and dust etc. Aircraft hangar and component workshop floors should be sealed to minimise dust generation.
Your 2nd post...provide proof as i don't believe this has occurred.