Sitting after the Third Rakaah of the Zuhr salaah and then proceeding to perform s fifth Rakaah

Q: Salaah-257: Our Imaam performed two Rakaahs of the Zuhr salaah properly but then sat after the third Rakaah. No one corrected him and he then proceeded to perform a fourth and without sitting again, continued to perform a fifth Rakaah afterwards. He then sat in Qa'dah after the fifth Rakaah and completed the salaah with the Salaam. When the followers brought it to his notice that he had performed five Rakaahs and needed to repeat the salaah, he said that the salaah was in order because he had performed the Sajdah Sahw. In fact, he added that even if he had not performed Sajdah Sahw, the salaah would still have been valid. Will the salaah of five Rakaahs be valid or not?

Answer: The Fardh of Zuhr will not be valid in the stated case and will have to be repeated, sitting after the fourth Rakaah was Fardh (obligatory) and even Sajdah Sahw would not have sufficed . If he had sat in Qa'dah after the fourth Rakaah and then performed a fifth Rakaah or gotten up for the fifth Rakaah and then sat down, the salaah would have been validated with Sajdah Sahw. And Allaah knows best what is most correct.

Fatawa Rahimiyyah vol.2