Cellar spiders, or daddy-long-legs spiders, are delicate long-legged spiders that build loose, tangled webs in basements, crawl spaces, and ceiling corners. Harmless and beneficial, they are mainly a cobweb nuisance in damp Whidbey structures.
How to identify cellar spiders
Tiny body with extremely long, thin legs spanning up to 2 inches, pale gray to tan. They vibrate rapidly in the web when disturbed.
Behavior & season on Whidbey & Fidalgo
They favor damp, undisturbed spaces — basements, crawl spaces, and corners — and build irregular tangled webs where they catch other insects and even other spiders. Active year-round indoors.
Why cellar spiders are a problem
They are harmless to people and actually eat other pests, so the only real issue is the abundant, messy cobwebbing they leave in corners and ceilings.
Signs of cellar spiders activity
- Loose, messy cobwebs in ceiling corners and basements
- Long-legged spiders that shake when disturbed
- Webbing accumulating in damp, quiet spaces
- Higher numbers where humidity is high
How Salty Dog treats cellar spiders
We remove webbing, treat harborage, and address the moisture and prey insects that make an area attractive to them. Learn more about our Spider Control service, or browse the full Pest Library.
Reviewed by Matthew — Salty Dog Pest Control. WSDA-licensed structural pest applicator (License #101709). Veteran- and family-owned, serving Whidbey Island, Fidalgo Island, and west Skagit County.
Frequently asked questions
Are daddy-long-legs spiders venomous to humans?
They are harmless to people. The popular myth about them being extremely venomous but unable to bite is false — they simply pose no threat.
How do I stop the cobwebs?
Reducing humidity and the insects they feed on, plus regular web removal and harborage treatment, keeps their numbers down.
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