Cellar Spider — Identification & Control

• Body — small (7-10 mm) elongated cream-to-tan, sometimes with darker chevron markings.
• Legs — extremely long, thin, and delicate; total leg span 30-50 mm, several times body length.
• Behavior — hangs upside-down from a loose messy web; when disturbed, vibrates the web rapidly in place (a defense against predators).
• Web — irregular, tangled, cottony; often extends across entire ceiling or wall corners in undisturbed spaces.
• Egg sacs — small clusters of eggs held between the female's chelicerae (fangs), not enclosed in a silken bag like most spiders.

Cellar spiders are one of the most beneficial predators to have in a Triangle basement or garage — they routinely capture and eat other spiders, including larger house spiders and occasionally young black widows. They also feed on gnats, mosquitoes, and small flying insects that wander into the web. In terms of biological control, they punch above their weight.

When disturbed, they respond with a distinctive whirl — vibrating the entire web so rapidly the spider becomes a blur. This is a defensive display, not aggression. They will drop from the web and retreat rather than confront a large disturbance.

Every few years the claim resurfaces that daddy long-legs spiders are 'the most venomous spider in the world' but with fangs too small to penetrate human skin. This has been tested and repeatedly debunked — including by mainstream science-education programs. Cellar spiders have short fangs (accurate) but their venom is not exceptionally potent. In documented tests where researchers permitted the spiders to bite, the result was a mild sensation lasting seconds, comparable to nothing.

They are not medically significant, they are not aggressive, and the mythology does not survive fact-checking. If you dislike the webs, address the webs — but there is no medical reason to fear the spiders.

Cellar spiders love undisturbed, dim, humid interior spaces:

• Basement corners and along overhead pipes.
• Crawl spaces, especially in the front corners near foundation vents.
• Garage rafters and corners.
• Attic corners.
• Behind furniture that is rarely moved.
• Inside seldom-opened closets and utility rooms.
• Under decks and inside covered porches.

They are largely absent from active living areas — they need long-undisturbed corners to build the sprawling cottony webs their catch strategy depends on.

Cellar spider control is fundamentally about the webs, not the spiders themselves. Approach:

• Regular web removal — vacuuming or brushing down webs breaks the population cycle by removing egg-tending females and preventing web recolonization.
• Perimeter and interior residual treatments in known harborage areas — basement joists, garage rafters, crawl-space corners.
• Humidity reduction — cellar spiders favor humid spaces; dehumidification in a basement or crawl-space encapsulation significantly reduces suitability.
• Insect reduction — reducing small insects reduces cellar spider food supply.
• Ongoing service — cellar spiders reestablish from nearby harborage; recurring service keeps webs suppressed.

Every plan is scoped with a personalized quote based on how much reduction the homeowner wants.

• Brush down cobwebs in basements, garages, and crawl spaces at least monthly during warm months.
• Reduce basement/crawl-space humidity — dehumidifier, vapor barrier, or encapsulation as needed.
• Declutter storage areas so corners are periodically disturbed.
• Improve lighting in basements and garages — cellar spiders thrive in dim spaces.
• Reduce small-insect entry by sealing gaps at basement windows, crawl-space vents, and garage doors.
• Consider tolerating a modest population in low-traffic corners — they eat other spiders and insects.