House Spiders

House spiders (Parasteatoda tepidariorum), commonly known as the American house spider, belong to the Parasteatoda genus. They’re described as synanthropic — meaning they live in close association with humans — and are found largely indoors across Canada, the United States, and other regions worldwide. This guide covers how to identify them, their behavior, and how to actually get them under control.

Identifying the house spider

House spiders take shelter in man-made structures — homes, barns, sheds. If you’ve noticed a lot of cobwebs building up around the house, this is usually the culprit. They have a bulbous abdomen and spin distinctively tangled, messy-looking webs.

1. Body shape

Females have an elevated, almost spherical abdomen and measure roughly 5-8mm in length. Males are smaller, with a more elongated abdomen, running about 3.7-4.8mm. Coloring is typically grey or brown with darker chevron markings on the body. Eggs hatch within about a week, after which spiderlings go through several instars — seven for females, six for males — before reaching adulthood. Adults can live a year or more, and unusually for spiders, males and females can cohabitate and mate multiple times rather than the more solitary pattern common in other species.

2. Color

House spiders are generally tan to yellowish-brown, with a dirty-white abdomen marked by dark stripes that meet at an angle. A female will lay roughly 250 eggs per silk sac — flask-shaped and brownish — and can produce over 3,700 eggs across 15+ sacs in her lifetime. Despite the numbers, house spiders are non-threatening and small; bites are painful but occur only in self-defense.

3. Legs

Like all spiders, house spiders have eight legs and two body segments, with no antennae or wings. They also have two pedipalps — small, leg-like appendages near the mouth used for sensing and feeding. If you’ve spotted spiders with unusually long, thin legs, those are more likely cellar spiders (commonly called “daddy longlegs”), found mainly in damp basements and cellars — roughly 20 species exist across Canada and the US.

One useful way to rule out a brown recluse: recluses have six eyes, versus eight in most spiders including the house spider. Their abdomen also lacks the chevron markings found on house spiders, and their legs are smooth rather than banded. Brown recluses also tend to favor warmer, darker, quieter locations than common house spiders.

4. Habitats

House spiders favor dark spots where they can trap insects like flies and camouflage from predators. Outdoors, they hide under leaves and around windows — especially near light sources that attract insects at night. Indoors, expect them in crawl spaces, garages, basements, window frame corners, closets, under furniture, and upper room corners. Because they build webs through trial and error, webs can accumulate quickly and collect dust — you may also notice spider droppings nearby.

Controlling house spiders

House spiders aren’t dangerous, but a heavy presence in a home understandably makes people uneasy. Here’s what actually works:

1. Direct-contact spray in cracks and crevices

A spider-labeled insecticide applied directly into cracks and crevices — not fogged into open air — can be effective, since contact sprays need to actually touch the spider to work. Avoid crushing spiders you find rather than spraying them, since a squashed egg sac can scatter spiderlings throughout the area instead of eliminating them.

2. Remove food sources

Spiders don’t eat human food, but the insects they prey on do. Cutting off that food supply for other pests indirectly starves out the spiders too. Keep food sealed, wipe counters, and clean up crumbs and spills consistently.

3. Seal entry points

Since house spiders feed on insects that get inside, blocking their food source’s entry points matters. Repair torn screens, seal cracks and crevices with caulk, and fix any drainage issues that create easy access.

4. Use glue traps

Place glue traps in dark, quiet areas — basements, along baseboards, near beds — where spiders are likely to travel. Spiders have strong vision and will move toward trapped insects on the glue board, getting caught themselves in the process.

5. Vacuum thoroughly

Regular vacuuming — including hard-to-reach spots like door frames, window frames, and baseboards — removes live spiders, egg sacs, and webs in one pass. It’s one of the more effective non-chemical methods since it physically removes the whole population rather than just visible adults.

How dangerous are house spiders?

House spiders aren’t dangerous to humans, but bites are painful — similar to wolf spider bites. The bigger issue for most people is the nuisance factor: webs, a general sense of unease, and the effort of cleanup rather than any real health risk.

DIY control works fine for most infestations, though a professional is worth considering for a persistent or heavy problem. Sealing cracks with a silicone-based caulk helps prevent new spiders from entering, and if spiders have already gotten in, vacuuming up webs, egg sacs, and live spiders is more effective than sweeping — sweeping alone lets most adult spiders escape.

Conclusion

House spiders pose little real health risk, but their webs and presence can still make a home feel unwelcoming. Prevention — sealing cracks, cutting off food sources for the insects they eat — does most of the long-term work. For active spiders, direct-contact sprays in cracks and crevices, glue traps in quiet corners, and thorough vacuuming are the methods that actually hold up, rather than foggers, which rarely reach where spiders hide.