don’t know how true this is, but i heard that cockroaches cannot stand chalk. Ordinary chalk that school teachers used to use when i was a nipper. Just draw a line around every opening where you think the roaches are coming from. They will not die straight away, ofcourse, but the chalk has the same effect on their “harnass” as the boric acid does. It eventually makes them “fall apart”.
Chalk will also discourage ants from crawling all over the place. They get confused when they reach a chalk line, and never cross it. They will always go around a line of chalk.