the technique I use is this:
#start
"_x setdammage 0" foreach [hh2,hh3, .............]
~2
goto "start"
where hh is the house name. Name each house hh2,hh3 etc
then name the above script, I call mine "build.sqs"
then exec the script from the init.sqs
as long as the house isn't destroyed withing every 2 seconds or so, it will never be destroyed