Villagers who attend the church, which has been forced to close, have now started a campaign to help fund the £60,000 needed to repair the damage.
It aims to cover £30,000 of the costs with the other half paid for by grants and insurance payouts.
St Helen's was one of five churches across the county to be targeted by thieves in the space of just four weeks in 2019.
Since the theft took place, the building's condition has deteriorated further due to it being exposed in bouts of bad weather.
Villager Dr Vicky Kemp, principal research fellow in the School of Law at University of Nottingham, who is behind the appeal, said: "The current state of the church is poor because of leakages and the longer it takes for us to raise funds, the more damage will be done to the interior of our church.
"We are opening windows to try and aid ventilation but we have noticed that some timbers are starting to rot.
"A new roof will mean that the church can once again be an important meeting place for the people of Plungar.
"We want the church to be restored to its former glory so that the people can enjoy this lovely building for many years to come."
The church was able to hold events for a while but it has now closed due to water leaks.
Events held over the Queen's Platinum Jubilee weekend have helped raise just under £5,000 towards the £30,000 target, but £25,000 in donations are still needed.
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