Q: If one had to make sajda sahu for a particular salaah, but forgot to do so. What is the po-
sition of that salaah? Must qadha be made for it?
A: If one realised immediately after the salaah that the sajda sahu was not made, then it is
permissible to still make the sajda sahu provided one had not yet turned away from qiblah or had not done anything to break the salaah. One would complete the salaah by reading ta-shahhud, durood, and qua again, then making salaam to the right and left. However, if the musallee had turned away from qiblah or had done any act that breaks salaah then the sajda sahu cannot be made. Instead, it is waajib to repeat that salaah if the time of the salaah is still
valid. If the time of salaah has passed then it is preferable to make the qadha of that salaah as
a precaution, because some of the Jurists maintain the view that qadha of such a salaah is still
obligatory. (Raddul-Muhtaar)