Jumu’ah prayers in a room at work
If in the city where you live there is a mosque in which Jumu’ah prayers are held, then you must pray with them, and it is not permissible for you to introduce another Jumu’ah prayer. But if there is no Jumu’ah prayer in the city, then you must establish it and it is not permissible for you to pray Zuhr instead, because “Establishing Jumu’ah prayer in their towns and villages is obligatory upon the Muslims and offering the Jumu’ah prayer in congregation is a condition of it being valid. There is no shar’i evidence that stipulates a certain number being required for it to be valid. In order for it to be valid it is sufficient for there to be three or more. It is not permissible for one on whom Jumu’ah is obligatory to pray Zuhr instead on the grounds that the number is less than forty, according to the most correct scholarly opinion.”
Fataawa al-Lajnah al-Daa’imah, no. 1794 (8/178).
It says in the fatwa of the committee no. 957:
“With regard to the number required to hold Jumu’ah prayers, we do not know of any text which stipulates a specific number. Because there is no text which stipulates a specific number, the scholars differed concerning the number required. Among the opinions which have been stated concerning that is the view that it may be done if there are three men who are local residents. This was reported from Imam Ahmad, and was the view favoured by al-Awzaa’i and Shaykh Taqiy al-Deen Ibn Taymiyah, because Allaah says (interpretation of the meaning): ‘come to the remembrance of Allaah [Jumu‘ah religious talk (Khutbah) and Salaah (prayer)]’ [al-Jumu’ah 62:9] – the verbal form used is plural, which implies a minimum of three.” (8/210).