if you want to get rid of roaches and ants this is how you can do it:

1) ensure the ceiling to roof is tightly closed- no cracks; manholes sealed

2) ensure all (!) windows are totally sealed and have zero gaps when closed.

3) all entrance doors need to have a all-around seal too that will close tightly. lockset without crawlway

4) make sure exhausts are sealed when not in use (not just shutters)

5) all water outlets must be either closed, carry a net seal or a trap to prevent roaches from getting in the house

6) all aircond piping must be sealed where exiting the house

we have done it and for the past 5 years i have not seen or noticed and roach (one got trapped before in the cooker hood, installed a mesh net at the exit, case closed) and exactly one trail of the tiny ants (they came through a crack in the wall left behind by the plumber when doing the kitchen sink).

i thought i shared with you guys what i did. its not that complicated. problem is that normally houses are too open with endless cracks. if you renovate with that in mind and close all entry points you'll end up pretty safe. mind you we life on an old rubber plantation and there are tons of ants in the garden - they just cant get in