Jabir (RAA) narrated that the Messenger of Allah (ﷺ) prohibited whitening a grave with plaster, to sit on it or to build over it (such as a dome).’ Related by Muslim.

وَلِمُسْلِمٍ عَنْهُ: { نَهَى رَسُولُ اَللَّهِ ‏- صلى الله عليه وسلم ‏-أَنْ يُجَصَّصَ الْقَبْرُ, وَأَنْ يُقْعَدَ عَلَيْهِ, وَأَنْ يُبْنَى عَلَيْهِ } [1]‏ .‏