Forgetting Sajda Sahu

Q: If one had to make sajda sahu for a particular salaah, but forgot to do so. What is the position of that salaah? Must qadha be made for it?

A: If one forgot to make sajda sahu and realised this immediately after the salaah, then it is waajib to repeat that salaah if the time of the salaah is still valid. However, once the time expires, there is no qadha to be made, because the faradh has been discharged.