Question about the heaven

What is meant by the sky being built or a building? For example in these next two verses Quran 2:22 and Quran 40:64 the word بِنَآءًۭ is used which i think means building. Quran 40:64 > "It is Allāh who made for you the earth a place of settlement and the sky a structure [i.e., ceiling] and formed you and perfected your forms and provided you with good things. That is Allāh, your Lord; then blessed is Allāh, Lord of the worlds." and Quran 2:22 > "[He] who made for you the earth a bed [spread out] and the sky a ceiling and sent down from the sky, rain and brought forth thereby fruits as provision for you. So do not attribute to Allāh equals while you know [that there is nothing similar to Him]." and in Quran 50:6 the word used is بَنَيْنَـٰهَا which means built i think > "Have they not looked at the heaven above them - how We structured it and adorned it and [how] it has no rifts?"