Will Sajdah Sahw be necessary when are recites the Qiraa'ah loudly in a silent Salaah or vice versa?

Q: Salaah-505: Will Sajdah Sahw be necessary when one recites the Qiraa'ah loudly in a silent salaah or vice versa? If so, after what amount of recitation will it become binding?

Answer: Sajdah Sohw will be binding if the Imaam recited three or more short verses, otherwise not. And Allaah knows best what is most correct.

Fatawa Rahimiyyah vol.2