Bugs in the basement

Basements collect the bugs that like cool, damp, dark places: cellar spiders, camel crickets, centipedes, silverfish, sowbugs and millipedes. A dehumidifier often helps more than pesticide.

Found in the basement

31 kinds, most dangerous first. Tap one for photos, the danger rating and what to do.

Why bugs end up in the basement

Basements sit against the soil, stay cool and are often humid. Camel crickets, pill bugs, sowbugs and millipedes live in damp soil and leaf litter outdoors, and foundation cracks and gaps under doors lead them inside. Once in, many die in a few days because the indoor air is too dry for them, which is why you may find several dead ones at once.

Spiders follow this steady supply of food. Cellar spiders, house spiders and funnel weavers build webs in quiet corners, behind storage boxes and around windows.

What you can do today

Run a dehumidifier and aim for indoor humidity below about 50 percent.
Seal cracks in the foundation and gaps around pipes, vents and the sill plate.
Store things in sealed plastic bins instead of cardboard, and keep them off the floor and away from walls.
Keep mulch, firewood and leaf piles a few feet back from the foundation outside.
Place sticky traps along walls to see what is coming in and where.

When it's more than a nuisance

Widow spiders and, in its range, the brown recluse are rated Get advice and like undisturbed basement clutter. Wear gloves when moving boxes that have sat for a long time, and shake out clothing and shoes stored down there. American and Oriental cockroaches often come in through floor drains in basements and carry germs.