Bawtry Phoenix Theatre is trying to raise £70,000 to replace the roof over the auditorium and stage at the Station Road venue.
The old chapel was converted in 1983 but since then the flat roof over the stage has had to be regularly repaired at considerable expense.
Beams in the roof of the chapel which were damaged by fire in the 1970s are also deteriorating.
The refurbishment project will see a replacement roof constructed over the auditorium and stage areas incorporating new storage space, supports for lighting, an electric film screen and curtain and air conditioning linked to a heating system.
Funding for the project could come from members of Bawtry Amateur Dramatic Society, Bawtry Phoenix Society, and Friends of the Phoenix Theatre, Phoenix Young Players, Arts Council and local charitable organisations.
Bawtry Town Council has also been asked if it could make a contribution to the fund so the work can start in May.
Members of the theatre have already completed a sponsored bicycle ride that brought in £2,000.