Said It Here

Is it safe to spray bug killer into walls with electrical wires?

Spraying liquid insecticide directly into wall cavities containing fiberglass insulation and electrical wiring creates serious risks of electrical short circuits and chemical saturation. Because carpenter ants nest deep inside these hidden spaces where baits like Terro only kill foragers, homeowners are forced to choose between risking unsafe DIY wall treatments or paying for an exterminator on top of costly old-house repairs.

What people tried

Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.

  1. 1
    Spraying the inside and outside perimeter with Alpine
  2. 2
    putting down Terro ant bait
  3. 3
    spraying insecticide with a wand into foundation cracks
  4. 4
    sealing holes with expanding foam
  5. 5
    patching cracks with mortar caulk
  6. 6
    spraying insecticide along indoor baseboards

In their words

Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.

r/homeowners1 person · September 2026

“Bought an old house (1895). There's definitely gaps in the siding and foundation where they're getting in and I've been working on that.”source ↗

“I've been putting down Terro since we closed on the house nearly 3 weeks ago that seemed to work at first, then a whole new wave of ants appeared so I must've just wiped out one of the nests.”source ↗

“My mom is acting like this is a HUGE deal and I ABSOLUTELY need to get an exterminator.”source ↗

“is it worth an exterminator? I already have a TON of work to do on this house so I don't know if it's worth spending money on that.”source ↗

Android16LikesBirds · r/homeowners · 7 upvotes
r/Pestcontrol1 person · September 2026

“Do you still spray Raid Ant and Roach into a wall that has insulation and electrical wires?”source ↗

“with so many coming out of that outlet suddenly at once, I’m guessing it’s a good idea to spray in the wall as well? What I’m concerned about is that wall cavity having fiberglass insulation and electrical in it and if that’s still safe?”source ↗

Mpm_277 · r/Pestcontrol · 1 upvotes

Where this came up

People with this problem also raised