DIY Cockroach Control

It’s been a long time since my last post but with damn good reason. I’ve spent the last two months on the greatest DIY experiment of my life — eliminating nature’s most resilient critter from my living space.

I live in a row house attached to Bloor Street in downtown Toronto. My home is directly connected to a variety of Korean restaurants, fruit markets and other residences. The building is probably a hundred years old, the plumbing is ancient, there are tons of holes, cracks, gaps in the wall and shoddy renovation work. Basically this place is a bug’s wet dream. The first roach showed up sometime in April 2010 and quickly invited all its friends.

My goal was to remove the little bastards from my apartment. Given the complexity of this experiment I decided to apply standard scientific method.


The roaches likely originated from the restaurants along Bloor Street; it’s equally possible one of my neighbours brought them in. Either way these old row buildings make it easy for bugs to spread, and they’ve likely covered the entire block by now.

As such, traditional roach control methods (traps, poisons) will likely have no effect. I can probably take out a few, but if they’ve taken over all the other buildings then there are far more bugs than I can possibly control. Moreover modern roaches are increasingly resistant to poisons.


  • Eliminating the entire bug population is probably not realistic.
  • Roaches do not strictly live in your apartment — they live in the walls.
  • Roaches are governed by the laws of physics and thermodynamics: they cannot teleport or pass through solid objects.
  • Instead of killing them, I will simply barricade them out of my home.

I was inspired by an excellent article I found online: How to Get Rid of Roaches by Caulking. I decided to apply the same strategy.


When the roaches first showed up, I performed some quick tests to see if they’d have any effect.

Several people suggested using diatomaceous earth to kill them off. I laid the stuff down everywhere but to no effect. No surprise… if the bugs are spawning from my walls, then killing a few odd specimens won’t matter.

I laid down a variety of traps, mainly glue pads. In nearly three months the glue pads trapped two bugs. I’ve actually watched the bugs dodge around these traps while fleeing my wrath.

I also tried leaving roach snacks: a mixture of Borax (boric acid), sugar and cocoa. They ignored these completely.

Clearly population reduction methods were ineffective. So I decided my best approach was to determine the bugs’ access point(s) to my apartment, then cut them off at the source.

Data Mining

Thus began a six week period of data gathering: observing the roaches, tracking their movements, noting areas of high concentration and trying to determine their point(s) of entry.

My particular flavour of bug was the Oriental Cockroach. They’re bigger bugs (~3 cm), very fast runners but not good climbers. They were not able to access high places like cupboards or shelves — once I caught one in my cutlery drawer, but otherwise they were all bound to the floor. They only came out at night and preferred dark areas, but did not run away from light either. When I wasn’t chasing them, they hung around in the same place and didn’t move much.

First priority was to determine where they were getting into the apartment. It was important to observe the bugs as quickly as possible after they got in. To accomplish this I waited around at night, turned down my lights, then every 30-45 minutes performed “sweeps” of the apartment. This way I was able to catch them at relative proximity to their points of entry.

For example, let’s say I check my bathroom at 12:30 AM and there are no bugs. Then I check the bathroom again at 1:00 AM and this time I spot one. Clearly there is a strong possibility the bug came through an access point in the bathroom. But maybe it came in through the kitchen and traveled to the bathroom? This is why I checked so frequently. I’d spent lots of time stalking the little bastards, and they didn’t travel too quickly — it’s unlikely one would move that far in thirty minutes. After catching several roaches in my bathroom at short time intervals, it’s reasonable to deduce there is a bug run here.

Obviously this method is not perfect and there are anomalies. But after several weeks of observation, several distinct trends emerged.

I noted a particularly high concentration in my kitchen: in and around the cupboards at the base of my sink, under/behind the fridge, under the oven and in the pantry. A few bugs in my bathroom. On rare occasions I’d find a bug in my bedroom. However the vast majority were in the kitchen, around the sink and fridge.

Last important point in data gathering: DO NOT KILL THE ROACHES. Dead roaches tell no tales. Unfortunately the live ones cannot be tortured for information… so instead I took a hockey stick and poked the bugs, forcing them to run back from whence they came. Many ran behind the fridge. Some ran under the oven. One ran into a hole in the wall under my kitchen sink (big mistake asshole!!!). Often they just ran around aimlessly in circles, fleeing for dear life.


This was some excellent data… now it was time to get to business. I made a trip to Home Hardware and bought a couple cans of expanding foam sealant. I already had lots of duct tape, diatomaceous earth and steel wool.

I then spent most of a three day weekend scientifically sealing up every crack, gap, and hole in the walls/cupboards/floors/baseboards of my kitchen. Naturally I paid special attention to the high-concentration areas. There were several cracks and holes in the cupboards beneath my sink (including the hole i chased a bug into). There were four significant holes at the base of the wall behind my fridge — this was a clear bug run. I blasted all these holes with foam sealant. My pantry was sealed up pretty tight but I plugged whatever gaps I could find anyway.

Basically I sealed up every hole I could stick a fingernail into, regardless if it was big enough to accommodate a roach. In fact, I sealed everywhere I even THOUGHT there was a gap. In the tight spots where I couldn’t see (like behind the radiator) I bombed the area with foam sealant anyway.

There were some gaps that were too big to seal with foam, especially around the plumbing — in these cases I stuffed the gaps with steel wool, then hit them with some foam for good measure. The walls behind my radiators were in poor shape, and these were nearly impossible to access. I taped over these sections of wall with duct tape.

Next I moved to the bathroom and sealed up gaps with the same degree of scientific precision. There were a few large gaps around the plumbing and under the sink, also behind the toilet. I even sealed a few gaps between the floorboards. I wanted to have absolutely no doubt there wasn’t even the slightest possibility of a bug getting through. After all given how fast cockroaches spread in these buildings, heaven forbid my neighbors ever get bedbugs…

Finally it was reasonable to assume that even if I’d stopped more bugs from getting into my apartment, there were still a few lingering about. So I bombed the critical areas with diatomaceous earth and Borax. From this point on it was a war of attrition — I would wear down and eliminate the survivors, then if they ever found a new way in, I would repeat this process until they were all gone.


Once I’d sealed off my kitchen and bathroom there was an instant, dramatic effect on the bug population. I didn’t spot a roach for several days. Obviously there were still a few kicking around, but when I found them they were in distant, unusual corners of my apartment and seemed really disoriented. One roach had been hiding under a tank of homemade liquor and was drunk as shit when I found it… I tried chasing it back to its source, but it just drunkenly stumbled around in circles until I got bored and killed it.

In the 2-3 weeks following my sealing bender, the number dropped off almost to zero.

Since June 22 (over four weeks ago!) I’ve seen one adult roach. It was slow and confused and had probably been hiding away for some time. I’ve also seen two baby roaches, who were probably small enough to crawl through some tiny access point I missed. If these visits continue then I’ll stalk them and cut them off, but they haven’t been frequent enough to worry about.


Needless to say this building is still crawling with bugs. I expect there are more access points in my apartment, and I expect to see more roaches in the future. If and when this happens I will apply the same method to push them out.

For the time being, I’m feeling pretty satisfied. It was a cheap and simple solution that only involved a lot of time and patience. I don’t think an exterminator would work here, and I love my apartment too much to move out. So I’m really glad I have it all to myself again!

This entry was posted in DIY. Bookmark the permalink. Post a comment or leave a trackback: Trackback URL.


  1. Posted October 3, 2011 at 1:35 am | Permalink

    13. I loved as much as you will receive carried out right here. The sketch is tasteful, your authored material stylish. nonetheless, you command get bought an shakiness over that you wish be delivering the following. unwell unquestionably come more formerly again since exactly the same nearly a lot often inside case you shield this hike.

  2. Charlene
    Posted January 24, 2013 at 2:32 am | Permalink

    This is my plan also. I did find one hiding spot that I was very surprised to find. I had hung a brand new carpet on my kitchen dining room wall. It has hung there for almost 5 years. I found 10-15 in the top corner and instantly killed them with a quick pot smacking. I should have taken pics. I am now worried that they may be hiding under my old living room rugs. I have lived here as mentioned for approx. 5 years. It has only been the past 3 years I’ve noticed them. Including recently a further infestation. I have paper in my kitchen cupboards. Which I will empty before I start my clean up. I will not move. I will re-do what you have done also if needed.

  3. novaflare
    Posted June 9, 2013 at 2:48 pm | Permalink

    rofl pure brute force. Works with mice to. I isolated every room in my old house from every other room using heavy card board. The mice can only jump about 2x ankle high. Then just turned our jack russel loose in each room in turn let him kill the mice then removed their carcasses lol worked great. I think isolation is the key for any pest. BTW if i recall roaches will not cross things like salt or wood ash. They do not know there is food on the other side. Seen kids starve a roach to death in a circle they burned in grass it ate all the grass inside then just walked around till it hit the burnt and kept looking for food and slowly starved. Even though food was a single inch away on the other side of the burned grass

Post a Comment

Your email is never published nor shared. Required fields are marked *

You may use these HTML tags and attributes <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>