عَنْ عَلِيٍّ، قَالَ: قَالَ رَسُولُ اللهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: " إِذَا لَمْ يُبَارَكْ لِلْعَبْدِ فِي مَالِهِ جَعَلَهُ فِي الْمَاءِ وَالطِّينِ "

Ali R.A. narrates that Rasulullah Salallahu Alaihi Wasallam is reported to have said, “When a servant is deprived of blessings in his wealth, then he spends his wealth in sand and water, that is, in putting up buildings.”

This refers to excess structures that are put up (over and above ones needs). If there is a genuine need for a structure to be put up due to necessity or for income, there isn’t any harm in doing so.