Quick Answers
Generally, it is not recommended to leave a wasp nest in your roof. Here are some quick answers about wasp nests in roofs:
- Wasp nests can be dangerous – wasps are aggressive and may sting if disturbed
- Nests will continue to grow over time as more wasps return each year, potentially causing structural damage
- Nests should be removed by a professional exterminator, do not attempt to remove them yourself
- Removal is recommended before winter, when wasp colonies die out except for new queens who hibernate
- Insecticidal dust or spray can be applied after removal to prevent new nests from forming
The Dangers of Wasp Nests in Roofs
There are several reasons why it is not advised to allow wasp nests to remain in a roof space:
- Risk of being stung: Wasps become more aggressive when their nest is disturbed. Leaving a roof space with a nest undisturbed can work temporarily, but any vibrations or noises from inspections, roof repairs or storms can aggravate them. Nests located near an attic entrance are especially hazardous.
- Colony expansion: Wasp colonies grow rapidly over the summer months and a nest that starts out small can reach the size of a beach ball by late summer. More wasps means more chance of accidental disturbances that lead to stings.
- Structural damage: As nests expand, wasps chew wood and other materials to make room and expand the nest structure. This can cause structural weakening and damage over time. Nests built around electrical wiring can also be a fire hazard.
- Difficult and expensive removal: Safely removing a large, established wasp nest often requires calling in professional pest control. Trying to remove a nest yourself risks being stung. Fumigation and nest removal can be costly compared to preventative treatment.
For these reasons, it is strongly recommended that any wasp nests found inside roofs be removed as soon as possible. Avoiding treatment and allowing the nest to grow is likely to create a more dangerous and expensive issue in the future.
When to Remove Wasp Nests from Roofs
Ideally, wasp nests should be removed from roofs:
- In early to mid-spring – This allows removal before queen wasps begin established colonies
- As soon as a new nest is spotted – Small new nests are easier to treat and prevent expansion
- Before peak summer activity – Less wasps means safer removal with lower risk of stings
- Before winter – Wasp colonies die out and contract diseases in winter except for hibernating queens
Roof inspections for nests are recommended in spring and fall when wasp activity increases. Attics and other roof spaces should be checked for the first signs of nest building so they can be promptly removed.
Removing Wasp Nests from Roofs
Here are some key steps for safely removing a wasp nest from a roof:
- Contact a professional pest control service – Do not attempt removal yourself
- Schedule removal at night when wasps are less active – Daytime removal risks more agitation
- Seal off attic access points and vents – This contains wasps and fumes during treatment
- Apply insecticidal dust or spray to nest and surrounding area
- Remove nest once wasps are dead – Use protective clothing and gear in case of any survivors
- Seal roof access points the wasps used to prevent reestablishment
- Check for and remove any other small starter nests
- Apply repellent perimeter treatments outside to deter other wasps
Proper personal protective equipment like suits, hoods and thick gloves should always be worn. Treatment is safest when temperatures are cooler and at night.
Preventing Wasp Nests
To help prevent wasp nests from forming in roof spaces:
- Install fine mesh screens on all attic vents, soffits and openings
- Seal any holes or damage that allows wasp entry
- Inspect for nests in spring and fall
- Apply preventative residual insecticide perimeter treatments
- Keep trees and bushes trimmed back from the roofline
- Deter wasps by limiting outdoor lighting at night
- Call a pest professional at the first sign of any nests forming
Taking proactive steps can help exclude wasps and make a roof space less desirable for them to start building nests. But if a nest does become established, never attempt removal without professional help.
Professional Removal Methods
Professional pest control companies have several effective methods for safely removing wasp nests from roofs:
Insecticide Dusts and Sprays
Pesticides applied directly into the nest kill wasps through contact. Dusts like deltamethrin cling to wasps and are carried throughout the nest. Sprays penetrate nest cavities. Insecticides like permethrin, tetramethrin and cypermethrin are common.
Fumigation
Fumigants like sulfuryl fluoride or methyl bromide gas permeate the nest galleries and voids within a structure. The gases kill wasps within the nest so it can be safely removed. The structure may need tarping.
Foam Treatments
Special foams containing pyrethrins for instant knockdown and an insect growth regulator are injected into wall voids and nest cavities. They expand to coat and penetrate the entire nest.
Removal and Disposal
After treatment, the dead nest is removed and disposed of. Protective equipment prevents any stings from survivors. The entry point is sealed up to prevent recolonization.
Follow-up Applications
Additional residual sprays, perimeter insecticide treatments, or installation of traps may be done to prevent formation of new nests.
Timing of Removal
| Time of Year | Benefits | Risks |
|---|---|---|
| Early Spring |
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| Summer |
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| Fall |
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As the table shows, early spring and fall offer the best combination of visibility for finding nests and lower wasp activity for safer removal.
Signs of Wasp Infestation in Roof
Look for these signs that wasps may have established nests in the roof:
- Wasps flying in and out of small cracks or openings
- Buzzing noises coming from voids and gaps
- Mud tubes formed on exterior walls or overhangs
- Wasps hovering near soffits, vents and roof edges
- Small grey paper-like nests visible in rafters
- Growing numbers of wasps around the home
- Stings from wasps when entering the attic
Any combination of these signs indicates it’s time to call for professional roof inspection and removal of any nests found.
Cost of Wasp Nest Removal
The cost to remove a wasp nest from a roof can range from $100 to $600 depending on factors like:
- Number of nests
- Size and maturity of nests
- Location difficulty and height work
- Amount of pesticides and materials needed
- Whether follow up visits and exclusion work is included
Larger infestations or difficult to access nests will be more expensive. Get an estimate from pest control to confirm pricing for your specific situation.
DIY Removal Dangers
It is never advisable to try removing a wasp nest from a roof yourself. Dangers include:
- Aggressive wasp attacks and repeated stinging
- Potentially deadly allergic reactions to venom
- Falls from ladders, roofs or attic spaces
- Accidental fires from knockdown agents like brake cleaner
- Ineffective treatment resulting in nest reestablishment
- Exposure to disturbed nest diseases like fungal infections
Roof nest removal should only be attempted by qualified professionals with training, protective gear, equipment and the right insecticides.
Conclusion
Wasp nests should never be left to grow untouched in roof spaces. Their expansion damages structures, and disturbing large, aggressive colonies puts you at risk of painful stings. Safely eliminating nests requires calling in pest control experts to treat and remove the nest, seal entry points, and prevent new colonies from forming. With their training and gear, professionals can remove roof nests while avoiding the dangers faced by DIYers. If signs of nests in a roof are spotted, it is critical to have them exterminated as soon as possible, before they expand and the risk of stings escalates.