To clear it up, I am mostly using sealing/caulking interchangeably in this text.

Some days ago I started seeing cockroaches in one room that is also connected to another bathroom. I caught 4 over an inch ones, but I saw a few small and very small ones too. I think they are Oriental and pretty sure not German, but anyways I need to take action right now, doesn't matter whether they are coming from outside or some spacings in the walls, I want to seal all holes.

Now I noticed patterns where they go and I noticed two holes. Both on the floor, one going into the wall the other into the floor (at the edge of the wall), I also noticed that my door moldings are not properly glued, they can be removed with a hand and nothing will hold them back, so there are spacings made naturally between door moldings and wall just because there is nothing to hold them to the wall, so I will need to close these too. My plan is to set up gel baits, and close them off (tell me if this is not the smartest idea, I know I can pour in boric acid too there, but I think gel baits will be better) - however the question is not about this but the following:

I have no idea what caulk/sealant should I use, acrylic, silicone or even plaster for such application? Yes, some of them is wall, other is probably some kind of plastic door moldings, so I might need to buy different types too, I want something that will hold up good. I do not think there will be any contact with water, however some water resistance would be good as one of these walls got pretty bad mold so I am guessing that that place is more suspicable to water (as it is closer to some pipes - which is probably a problem on its own, so I might need to take that into consideration when choosing what type of sealant? Also, how important would be the gun for it, how much should I invest in it?

  • I put a lot of borax between the walls during construction and this has greatly reduced roaches in the house. So, If there is any way to blow or otherwise get borax powder into the holes before you seal them , it will reduce numbers. Sep 26, 2019 at 17:46
  • So borax over gel baits?
    – appwizcpl
    Sep 27, 2019 at 23:36
  • I never used gel baits , but use both ; borax is cheap and my guess is gel bait is not expensive. PS - I am in E TX , an epicenter for roaches. Sep 29, 2019 at 18:28

1 Answer 1


Just get a quality silicone caulk and go through the house caulking every opening. Get one that's paintable. They also come in a variety of colors so you might not have to paint over them. This type of caulk is water proof so if it comes in contact with moisture, you'll be ok. This will work on just about every surface there is. It also comes in tubes so you might not need a gun. The guns are inexpensive and you can get all this stuff at your home store. Good luck.

  • Agree. You want something flexible not plaster. You'll be using a lot so get a caulking gun, some of the cheaper ones are quite hard to squeeze so don't get the cheapest. Sep 26, 2019 at 21:49

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