Cellar spiders and house spiders breed year-round in Ontario basements. Discover the key steps to reduce moisture, block foundation entries, and eliminate them permanently.
Spiders are attracted to basement spaces because they mimic their natural outdoor habitat: cool, damp caverns. High humidity levels attract moisture-loving insects like silverfish, sowbugs, and springtails, establishing a thriving food chain. Undisturbed storage areas under stairs and in utility rooms give spiders plenty of quiet corners to breed.
Condensation on cold concrete walls and poor ventilation create the humid environment crawling pests require to survive.
Moisture-loving insects concentrate in basements. Eliminating their food supply is critical to controlling the spiders.
Ceiling joists, storage areas, and utility rooms provide undisturbed spaces where spiders breed continuously.
Follow this checklist to make your basement inhospitable to spiders and crawling insects:
When DIY methods aren't enough, Spider Squad offers a specialized interior and exterior treatment system to clear the basement source population.
We treat the wall-floor junctions, sill plates, ceiling joist corners, window wells, and areas behind utility pipes using professional-grade residual products.
Our exterior perimeter treatment creates a barrier that stops crawling insects and spiders from entering your basement through exterior gaps and foundation lines.
What is the best way to get rid of spiders in my basement permanently?
The most effective method is combining dehumidification (keeping humidity under 50%), sealing foundation entries, and applying an interior baseboard treatment with an exterior perimeter foundation barrier.
Do basement spiders crawl upstairs?
Yes. As the basement population grows or when temperatures drop, male spiders and hatchlings will search for new territories and mates, moving up stairwells and through utility gaps into upper living spaces.
Are cellar spiders dangerous?
No. Cellar spiders (often called daddy long-legs) are completely harmless to humans. However, they breed year-round and build messy cobwebs that can quickly make a basement look neglected.
Professional Basement Treatment
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📞 437-747-7823 Basement ServicesPremium Protection
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Our flagship exterior structural barrier targets the full perimeter of your home — foundations, soffits, window frames, eaves, and all entry points. Repels and eliminates spiders, ants, and crawling insects before they enter.
A comprehensive yard-level barrier applied to shaded vegetation, ornamental shrubs, deck skirting, and property borders. Reduces adult mosquito and tick populations around your outdoor living space.
SpiderShield™ perimeter barrier
SpiderShield™ creates an invisible exterior barrier that prevents more than just spiders — blocking ants, earwigs, crickets, and other seasonal crawlers from entering your home.
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Spider Squad is a family business — not a franchise, not a call centre. Our team lives in the communities we serve, which means faster scheduling, real accountability, and treatments designed for the pest pressures specific to this part of Ontario.
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