Why Do I Keep Getting Spiders in My Basement?
A Simple Guide for Canadian Homes, Especially in Calgary and Edmonton
If you keep finding spiders in your basement, you’re not alone. This is one of the most common issues in Canadian homes, especially in cities like Calgary and Edmonton, where climate and housing styles create ideal conditions for spiders to settle in.
Here are the main reasons it happens and what you can do about it.
Basements Are Comfortable for Spiders
Most basements in Canada are quiet, cool, and dark. These are conditions spiders naturally search for, so basements give them a safe place to hide and hunt.
In Vancouver, the higher humidity and mild temperatures make basements even more appealing. In Calgary and Edmonton, basements stay warmer than the outdoors during the winter, so spiders move inside for shelter.
Spiders Follow Their Food
If spiders are showing up, it usually means other insects are already living in the basement. Spiders eat silverfish, ants, flies, beetles, moths, and other small bugs.
Each city has its own pattern.
- Calgary: Temperature changes encourage ants and flies to move indoors.
- Edmonton: Long winters push many insects inside, giving spiders a consistent food source.
The more insects you have, the more spiders you’ll see!
Small Openings Let Them In
Even the smallest gap is enough for a spider to enter. Many Canadian homes, especially older ones, have tiny cracks in the foundation or openings around windows, pipes, vents, or doors.
Vancouver homes often deal with moisture-related cracks. Calgary and Edmonton homes are affected by freeze and thaw cycles that create small openings in concrete and exterior walls.
Storage Areas Create Hiding Spots
Most basements in Canada double as storage rooms. Boxes, old furniture, seasonal clothing, and clutter all create perfect hiding spots for spiders.
Cardboard boxes are especially attractive because they hold moisture and break down over time. Pro tip! Switching to sealed plastic bins can make a big difference.
Moisture Problems Attract Bugs and Spiders
Moisture is one of the biggest reasons spiders and insects gather in basements.
- Calgary and Edmonton deal with condensation, snow melt, and limited airflow in basement spaces.
Signs of moisture include a musty smell, damp walls, condensation, and peeling paint. If your basement has any of these, it becomes a comfortable environment for insects, and spiders will always follow.
Lights Draw Insects, Which Bring Spiders
Indoor and outdoor basement lighting can attract flying insects. This is especially common during Vancouver’s mild evenings or during summer in Calgary and Edmonton. Once insects gather near the house, spiders don’t take long to show up.
How to Reduce Spiders in Your Basement?
Here are simple steps that help most homeowners:
- Reduce moisture: Use a dehumidifier, repair leaks, and improve airflow.
- Seal entry points: Fix cracks, add door sweeps, and repair window screens.
- Deal with other insects: Reducing bugs removes spiders’ food source.
- Declutter: Replace cardboard boxes and keep stored items off the floor.
- Maintain the exterior: Keep plants, leaves, and debris away from the foundation.
These changes often lower spider activity within a few weeks.
When to Call a Professional?
It’s worth calling a pest control specialist if spiders keep returning regularly, if you’re seeing large numbers, or if you suspect other pests are living in the basement. Trust professionals such as Ecopest in Calgary and Edmonton, who understand the specific conditions in each area and can identify the root cause of your problem.









