I have been praying for the past 6 years after realising the correct sources of fiqh i.e. following a madhab. During this time I have made mistakes and have tried to rectify them. E.g. I would say Allahu akbar before raising hands for takbeer tahrima or I would not place at least 3 fingers of the feet to the ground during sujud. I prayed quite a few salaah with jamaa. Now however, I feel I have a good understanding of both prayer and purification and would like to know whether I am required to repeat such prayers as Qada.
It is necessary that both feet are on the ground for the sajdah to be valid. During the whole duration of sajdah at least one toe must be on the ground. If one lifted both his feet of the ground and then put it back on the ground straight away his sajdah would still not be valid. (Fatawa Darul Uloom Deoband p.35 v.4)
Regarding your question, as mentioned in an earlier fatwa entitled “Qadha Prayers” which can be viewed from the Darul Ifta Birmingham website you will have to estimate how many Salahs you may have prayed in such a way and do qadha of it.
Only Allah Knows Best
Mohammed Tosir Miah
Darul Ifta Birmingham