وَلِمُسْلِمٍ عَنْهُ: «نَهَى رَسُولُ اَللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: أَنْ يُجَصَّصَ الْقَبْرُ، وَأَنْ يُقْعَدَ عَلَيْهِ، وَأَنْ يُبْنَى عَلَيْهِ»
The Messenger of Allah (sallallahu alayhi wa sallam) prohibited whitening a grave with plaster, to sit on it or to build over it (such as a dome). Related by Muslim.
Bulugh al-Maram 688, Book 3, Funerals, Hadith 48. 1 min read