Wasp nest removal

A wasp nest is the one pest problem where the risk is immediate and physical. Health Canada notes that unlike bees, wasps can sting more than once, that removal can be dangerous because of the risk of attack from grouped wasps, and that professional help is recommended for an active nest (Health Canada, wasps). That is the whole argument for not doing this off a ladder on a Saturday afternoon.

Know what you are looking at. Yellow jackets are the aggressive ones that turn up at picnics, often nesting in the ground, in wall voids or under soffits, and Health Canada identifies German yellow jackets as the most problematic social wasps. Bald-faced hornets build the large grey football-shaped nests in trees and under eaves. Paper wasps build small open umbrella-shaped combs under railings and deck furniture and are comparatively docile. Yellow jackets and hornets run about 10 to 25 mm with black and yellow or white banding.

Understand the season. A nest starts in spring with a single queen and is trivially small. It grows all summer, and Health Canada notes that wasps are more abundant and active in late summer. By August and September a yellow jacket nest can hold thousands of workers, and that is precisely when the colony switches to seeking sugars and becomes most intrusive. A nest found in June is a far easier problem than the same nest in September.

Step one: locate the nest properly. Watching the flight path is the reliable method. Wasps entering a hole in a soffit or a crack in siding mean a void nest, which is a different job from a visible aerial nest. Ground nests are found by traffic at a hole in the lawn or under a step. Treating the wrong opening leaves an angry colony and a homeowner who now has to call anyway.

Step two: timing the treatment. Health Canada recommends spraying after nightfall because wasps are less active at night, and suggests using a red-filtered flashlight so as not to alarm them. Cool early mornings work as well. Treating a nest in the middle of a warm afternoon puts the maximum number of defenders in the air.

Step three: treatment. An aerial nest is treated with a registered product applied into the entrance, then removed once activity stops. A void nest is treated at the entry point with a dust that workers carry inside, and crucially the entrance is not sealed immediately afterwards, because sealing a live nest in a wall drives wasps into the living space through light fixtures and outlets. Ground nests are treated at the opening.

Step four: removal and prevention. The nest is removed where it is accessible, which prevents wasps being attracted to the site and prevents secondary insects feeding on the remains. Void entries are sealed after the colony is confirmed dead. Health Canada's preventive advice is practical: cover garbage, do not leave pet food or picnic leftovers exposed, keep food covered outdoors, and avoid scented products. Commercial traps baited with protein rather than sweets can help, though they draw wasp activity toward the trap.

How long it takes. Most nest treatments are a 20 to 45 minute visit. Activity typically stops within 24 hours, occasionally up to 48 for a large void nest. Some residual traffic from returning foragers for a day or two is normal and not a treatment failure. Sealing a void entry is a follow-up a few days later.

What it costs in Ottawa in 2026. Indicative ranges, matching this site's price guide. An accessible nest generally runs $100 to $200. A nest in a wall void or underground is $200 to $500, because it takes longer, needs different product and often needs a return visit. Multiple nests or a high roofline cost more, and emergency or same-day service carries a premium. Late August is the busiest fortnight of the year for this work, so booking ahead where the nest is not urgent saves money. Sealing entry points afterwards may be quoted separately.

When to leave it alone. Health Canada notes that where a nest is not causing a problem it is best to leave it until November or December, when it is abandoned. Wasps do not reuse an old nest, colonies die off with the hard frost, and the nest can be removed safely in winter. A high paper wasp nest under a soffit that nobody walks beneath is a reasonable candidate for waiting. A yellow jacket nest beside a back door is not.

What makes an Ottawa house different. The season is compressed here. Colonies build from May, peak from late July through September, and are killed by the first hard frosts, which in Ottawa usually arrive in October. That gives a short, intense window when calls spike, and it means a nest discovered in late September may genuinely be worth leaving. Locally, the aluminium and vinyl soffit on suburban houses through Nepean, Orleans, Kanata and Barrhaven offers ideal void space behind it, and decks and sheds are the other common sites. Anyone with a known sting allergy should treat a nest near an entrance as urgent and should not attempt any part of this themselves.

Who should do the work, and the licence. Aerosol wasp products are sold retail and a small, low, accessible paper wasp nest is within reach of a careful homeowner at night. Beyond that, call someone. For commercial application, Ontario requires a pesticide exterminator licence in the structural class and a pesticide operator licence for the business, under the Ministry of the Environment, Conservation and Parks and O. Reg. 63/09 (Ontario, pesticide licences and permits). Ask, particularly of a same-day operator you found in a hurry.