Fire crews from Rotherham and Elm Lane stations were called to the United Reformed Church in Kimberworth Road, Bradgate, Rotherham, at 11pm on Thursday, August 18.
Upon arriving at the scene, they found the back of a community building close to the church was well ablaze.
A spokesman for South Yorkshire Fire and Rescue said: “The ground floor was well alight and the blaze would go on through to the roof, before the floor collapsed into the basement.
“Fire crews immediately got to work to prevent the fire from spreading to the main part of the community hall and the nearby church.
“They were successful in containing the blaze in a near-four hour operation. Firefighters left the scene at 3.07am.”
An investigation into the cause of the fire was set to be launched yesterday, the fire service spokesman added.
It is too early to say whether the fire was deliberately started.