I grew up poor in Chicago, I can tell you about roaches. You really want to get rid of them? Ok, here is what will work, guaranteed. I used this method on several apartments; when I was first married we lived in a small apartment in a nice area, but it was infested with the little curses. I did my thing and within 2 days there were no more roaches. The rest of the tenants were about to sue the landlord, but we were fine- they had the roaches and we didn't. The young woman in the apartment below was being driven bonkers by them and asked for help, so one Saturday afternoon I worked on her apartment, and the roaches stopped in her place. She literally baked us a cake for thanks (it was good, to!).
The principle is that roaches access your apartment from between the walls. They actually aren't living in your apartment, they come out at night. What you do is plug all the access points, and then kill the remaining ones trapped in your apartment. Finis.
You work on all the rooms in the apartment, but the main problem rooms are the kitchen and the bathroom. Go to a hardware store and get a couple of tubes of the cheapest latex caulk with a caulking gun. Check under the Kitchen sink and Bathroom link, shower and tub; where the supply pipes and the drain pipe come through the wall usually are gaps around the pipes. Caulk all around those. If the holes are too large, cut pieces of thin aluminum sheeting, masonite - anything - and tape or glue them tight around the pipes to seal the pipe holes. Now pull out the refrigerator and stove and caulk the baseboards behind them. Examine all the baseboards and run a thin line of caulk where ever there are gaps of any kind. Do this for every room including closets.
After that, sprinkle a thin line of ortho Boric Acid (I like the brand called Roach Pruf, but there are others) around every room's perimeter, at the bottom of the baseboards only, including under the kitchen sink, bath, behind the refrig and stove. Seal any crack you see that accesses into the wall. That's it. By the way, don't forget to staple a cheap felt strip to seal the gap under the front door (if there is one). Believe me, this will work.
Edited by ranchhand_, 07 December 2015 - 05:42 PM.