Based on your quotation, they put there the grill is 1.5 inch (hollow), the 1.5 inch is not the issue, you need to ask specific the thickness of the grill, because the thickness of the steel is the impact if the grill can be easily cut.

You has nice yard, the yard is the easy target to come down, so the thickness of the grill play roll for your family safety. Maybe i think too much, but i saw your initial picture of how the ceiling got the hole, they may be some occupancy during the abandon period.

Bought it for RM380K.
The house almost get in auction.
But my best friend is a lelong bos and he offered me the house.
If go in lelong, the price can jump up to RM500K++.
Without thinking further, i take it...
Few months back, there is someone offering the house for RM500K.... 
I dont feel selling it is a good idea. 
Hehehehe

I help her paint with white colour.
Hehehe
If want other colour, go and buy herself.. 

Bad neighbour.