what 's the meaning of "building envelop"

Building envelope is actually like what the above said, says the external parts that enclosing the whole building. However, I think that something is missing which ambient temperature; mositure; solar radiation; sound effect and vibrations should also be the subject of one. This is important for building services engineers to know all these information. So that the engineer can have a suitable design in respecting the particular use of the premise base on the above information.

In other words, "building envelop" should widely defined as the "phenomemon" affecting the occupants and the building itself.

It means building facade. All component exposed to external air.