Sayyiduna Jabir bin Abdullah (may Allah be pleased with them both) and Sulayman bin Musa narrate that the Messenger of Allah (peace and blessings be upon him) forbade that a structure be built over the grave, or that extra earth be added to it, or that it be plastered.
Also, Jabir (may Allah be pleased with him) narrates from the Prophet (peace and blessings be upon him) that he said: "No extra earth should be added to his grave."
The first hadith suffices; Aban is da'if (weak).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 6735