If Mumtaz is taken to have died around 1631 as is commonly believed and it took 22 years to construct the Taj. We have on record a letter from Prince Aurangzeb a year earlier i.e.1652.
In that letter Aurangzeb records in itself that the several rooms on the second storey, the secret rooms and tops of the seven storey ceilings have all absorbed water through seepage and were so old that they were all leaking, while the dome had developed a crack on the northern side. Aurangzeb, therefore, ordered immediate repairs at his expense while recommending to the emperor that more elaborate repairs such as the roof be opened up and redone with mortar, bricks and stone
THUS FROM AURANGZEB'S NOTING IT IS APPARENT THAT IN 1652 AD THE TAJMAHAL BUILDING HAS BECOME SO ANCIENT THAT IT NEEDED ELABORATE REPAIRS.

Aurangzeb's letter is recorded in at least three chronicles titled 'Aadaab-e-alamgiri ', 'Yaadgaarnama 'and the ' Muraaqqa-I-Akbarabadi ' (edited by Said Ahmad, Agra, 1931, page 43, footnotes 2).