Q. Can an exercise room be built adjacent to a Masjid?
A. Building an exercise room adjacent to the Masjid is allowed if the purpose is to encourage fitness and exercise which is commendable in Islam provided that the sanctity of the Masjid (appropriate clothing, no music etc.) is upheld at all times. The exercise room should be for the use of the congregants of the Masjid. The exercise room must be closed during Salaah times. (Kitaab-Ul-Fataawa 4/230-231)
Allah Ta’ala Knows Best
Mufti Ismaeel Bassa
This answer was collected from TheMufti.com, which is a fatwa portal managed by Mufti Ismaeel Bassa from South Africa.