Rules of an Invalid Ghusl | Islamic Laws by The Leader Ayatullah Ali Khamenei
Rules of an Invalid Ghusl
Q 193: Someone reaches the age of shari puberty but does not know that ghusl is obligatory and how to make it; and in this way he passes about ten years before coming to know about taqlid and that ghusl is obligatory? What is his duty concerning qada of his fasts and prayers?
A: It is obligatory for him to do qada of the prayers offered in the state of janabah. Also it is obligatory to redo the fasts if he knew that he was junub but did not know that ghusl is obligatory for him for fasting.