We have a nearly 100 year old stone church building with a timber roof construction, a slate roof and a cedar ceiling in the sanctuary

We have a nearly 100 year old stone church building with a timber roof construction, a slate roof and a cedar ceiling in the sanctuary. We have two questions. 1. is the timber roof structure still sound and does it need any attention (e.g. tightening of bolts, etc.). 2. Is there a way we can insulate the roof to avoid heat loss from roof. We have been told that the heat is needed to melt the snow from the roof to prevent ice damming with resultant water leakage into the sanctuary through the walls. At this point we just need inspection and advice on further action. We are at a point in our congregation where we are limited in available funds but we want to reduce operating costs if the required repair work is not excessively expensive! We do not have pictures at this time.