my contractor told me adding zinc sheet will definately void your house insurance. Instead, they recommed adding horitonzal kayu masak truss small enough gap ppl cannot get thru. At least if fire bomba wafer still can get thru from the roof.Quoted ~7k for the whole job , mine is a dst house.

Thats good value , they quote me all in 7k , take out roof and place the wood + labour cost