When you are building the house and before the walls are rocked, pour LOTS of boric acid in all the outside walls over the studs. You might get a few cockroaches in the house, but they will be obviously sick and there won't be many of them.
We did this in our own house and roaches are a big problem in our area and when I do see one, they are very slow or they have already assumed the postion and have their feet flailing in the air.
