Centipedes

• WHAT YOU SEE

One long, fast, many-legged centipede crossing the basement floor, gone under a box or behind the water heater before you can get a good look. They're startling because of the speed, not because there are a lot of them. Finding one in a bedroom or living room is much less common than finding one in the basement.

• WHAT WE SEE

Centipedes are predators, not scavengers, so finding one means there's something smaller for it to eat and enough moisture for both of them to live on. In a basement that's usually a sow bug, a silverfish, or another small insect population feeding on damp cardboard or a moisture problem at the sump. Seeing a centipede is often the first sign of a bigger, quieter issue rather than the problem itself. They favor damp, dark, undisturbed spots: behind stored boxes, under a workbench, along a foundation wall that stays cool and wet.

• HOW WE FIX IT

We treat the basement directly, along the sill plate and foundation wall where centipedes and the insects they're hunting both travel. Sealing the gap around the dryer vent and the sill plate closes off two of the most common entry points. If there's standing moisture at the sump, we'll say so, because drying it out removes the food supply for everything downstream of it, centipedes included. Exclusion plus the quarterly exterior barrier is usually enough to keep the population from rebuilding.

• WHEN THEY SHOW UP

Centipedes are worst in fall and winter, when cooler weather pushes them toward a basement that stays warmer and damper than the yard. A damp basement can host them any time of year, cold weather or not, if the moisture problem never gets fixed. The living room and foundation see centipedes occasionally too, usually near a damp wall or a gap at grade. The basement is where we find them most.

• WHAT THE PROS KNOW

Centipedes are the predator, not the problem. Seeing them means there is something for them to eat and enough moisture to live on.