Centipedes in Calgary: House Centipedes and How to Get Rid of Them
Quick answer: The centipede running across a Calgary basement floor is almost always the house centipede, and it is there because the space is damp and because there are insects to eat, usually silverfish or spiders. Killing the ones you see does not reduce the population. Drying the space, sealing the gaps and controlling the prey insects does.
Which centipede do you have?
Calgary homes only really deal with two groups:
- House centipede (Scutigera coleoptrata). Grey-yellow with darker stripes and 15 pairs of long legs. Very fast, indoors, usually seen at night near a drain, baseboard or basement wall. This is the one that alarms people.
- Soil and garden centipedes. Shorter, slower, and they belong outdoors under stones, in mulch and in garden soil. They wander into garages and basements in spring and fall and usually die indoors.
Are they dangerous?
House centipedes have venom, but it is used on insects. Their jaws are too small to break human skin in most cases, and at worst a bite feels like a mild insect sting with a small red mark. They are not aggressive and they run from people. They are not a health risk to cats or dogs.
Why house centipedes appear in Calgary basements
Two conditions have to be right, and both are usually present together:
- Humidity. Damp foundation walls, floor drains, sump pits, leaky laundry connections, crawl spaces and poorly ventilated bathrooms. Older Calgary homes with wet basements and properties near the river corridors see the most.
- Prey. House centipedes eat silverfish, spiders, small ground beetles and cockroach nymphs. No prey, no centipedes.
That is also why a centipede sighting is useful information: it usually means there is another insect population living in the same damp space.
Why killing them one at a time does not work
House centipedes live in wall voids, baseboard gaps, floor drains, sump pits and crawl spaces. The ones you see crossing the floor are a small fraction of the population, and they travel through plumbing chases and service voids between rooms and even between units. Squashing one leaves the moisture and the food supply untouched.
How to get rid of centipedes in a Calgary home
1. Dry the space out
Run a properly sized dehumidifier in the basement, target 50 to 55 percent relative humidity, dry floor drains between uses, fix any dripping pipe or laundry connection, and ventilate crawl spaces. This is the single most important step.
2. Seal the routes
Seal foundation cracks, gaps around pipes and wiring, and the baseboard gaps where they travel. Door sweeps on basement and garage doors stop the outdoor species coming in during the spring and fall transitions.
3. Take the clutter off the floor
Stored cardboard, boxes and bags against a damp wall are ideal harbourage. Raise storage onto shelves or pallets and keep a clear margin around the foundation wall.
4. Control the prey insects
This is the step most homeowners miss. If silverfish or spiders are active in the same space, centipedes will keep returning no matter how many you remove. Treating the damp harbourage for those insects is what ends the cycle.
5. Treat the harbourage, not just the floor
A professional treatment applies product to the damp harbourage areas, wall voids, drain surrounds and crack lines where house centipedes actually live, then confirms the population is down on a follow-up visit.
What centipede treatment costs in Calgary
Centipede treatment starts at $300, depending on how much damp harbourage has to be treated, whether wall voids and pipe penetrations are involved, access to crawl spaces and sump pits, and whether a prey insect population such as silverfish also needs treating. See our centipede control Calgary page for details, our silverfish control Calgary page for the damp-area insect they usually feed on, or pest control prices Calgary for every service.
Prevention that works in Calgary's climate
- Dehumidifier running in the basement from spring through fall
- Floor drains and sump pits dried between uses
- Crawl space vents clear, and vapour barrier intact
- Foundation cracks sealed, pipe penetrations caulked
- Storage off the floor and away from the foundation wall
- Annual basement inspection after the spring melt
When to call Calgary Pest Guard
Call (825) 760-5364 if you are seeing house centipedes every week, if they are showing up in bedrooms or bathrooms, or if a tenant or family member is uncomfortable living with them. We identify the moisture source and the prey insects, treat the harbourage, and give you the humidity plan that keeps centipedes out. Licensed, insured, and every treatment is guaranteed.