Hi all , i've done digging the threads but cant seems to find a straight forward solution in preventing ppl coming from the roof.
I need some info as below :

1-is adding extra roof trusses ( narrow the gap ) really works in preventing ppl coming in from roof?
2-if i just cover the ceiling board with wood trusses , will it be better than no 1?
3-i dun want to put zinc cos it will void the fire insurance - any comment?
4-any good recommendation for contractor in jb area？

thanks