Fact Sheet On Pests

Reprinted courtesy of: AmeriSpec of Simcoe Muskoka

Q. What are some typical pests encountered in Canada that can affect my home?

A. Household pest types vary significantly across Canada and include animals such as birds, bats, mice, squirrels, raccoons, etc. and insects such as termites, powder post beetles, ants, and stinging insects. Pests can enter a house through common building openings such as chimney flues, roof vents, dryer/bathroom/ kitchen fan vents, openings in soffits/fascia, holes in window/door screens, the top of an overhead electrical mast, or utility penetrations in the foundation. Most insects and some small animals (i.e. mice), can access the home through holes as small as ¼” in diameter. Wood boring insects are unique because they don’t need a hole in a building for entry; termites and powder post beetles typically often enter the home through exposed wood on the lower perimeter of a home.

Q. What are some health and safety concerns associated with pest entry into my home?

A. Several health and safety concerns associated with pests are summarized below:

Mice and other rodents can chew through electrical wire sheathing and pests sometimes build nests or hives in electrical panels, creating a potential electrical safety issue that may be a shock hazard or cause a fire. This emphasizes the importance of responding quickly to control/remove pests at the first sign of pest activity in a home. Licensed electricians should also be consulted if repairs to electrical systems are required.

Bird or rodent nests built in chimney/exhaust flues can go unnoticed through the summer, but when colder fall nights arrive, the nests can prevent proper venting and cause combustion gases from appliances to back up into the home, causing harmful exhaust gases (such as carbon monoxide) to enter the home. To enhance safety, proper spark arresters should be installed at the peak of all chimney flues to prevent pest entry and chimneys should be inspected annually by a qualified contractor to ensure there are no blockages in the chimney.
Certain bird and bat feces can grow a fungus that is toxic and causes a disease called histoplasmosis, a potentially serious illness. If bird/bat feces are present in an attic, it should be left undisturbed or removed by a qualified contractor who will have protective clothing and who be able to dispose of the waste safely and properly.

Holes that are created when an animal enters a building often create pathways for moisture to enter into a building’s attic, walls, etc. The moisture may be concealed and unable to dry for long periods of time. This environment is ideal for mold growth, which could potentially be a health concern, especially if residents have mold allergies.

Q. What type of common building damage do pests cause?

A. Some of the more common types of building damage caused by animals include:

Shingle deterioration can occur if animals continually walk across a roof or if persistent bird excrement is present. Raccoons can actually tear shingles off a roof to gain attic access. Other animals access attics by damaging soffit/fascia or roof vents. In addition, resultant water entry into a home through very small openings caused by pest intrusion can cause many problems ranging from cosmetic damage to interior finishes to wood rot of structural framing, if moisture persists for extended periods of time.

Wood boring insects such as termites, powder post beetles, or carpenter ants can cause significant damage to wood structures in a home. Unfortunately, this damage is often hidden behind walls and is not detected for a long period of time and after pest infestation has occurred.

Larger animals such as raccoons compress insulation when rummaging about in an attic, in some cases to 25% of the original thickness. This greatly reduces the air spaces in the insulation materials and makes the insulation less effective. Following pest removal, compressed insulation should be carefully “fluffed” or in some cases retrofitted with additional insulation to restore/improve energy efficiency in this area.

Q. What are some control techniques that are available to control pest activity in my home?

A. Unique pest problems often require specialized/unique solutions that can be offered by qualified contractors, however, there are several common control techniques that homeowners can often use, summarized as follows.
Seal any openings larger than ¼” on the exterior of the home. This may involve repairing sections of trim, installing vent screens or spark arresters on chimney flues, and ensuring any other openings are properly sealed. Large tree branches should be cut away from the roof to reduce accessibility to the home. If animals such as mice have already entered the home, setting traps/bait to control the mice is often effective. If mice persist or if other larger animals are already in the home, we recommend consulting a qualified pest abatement contractor for assistance.

Since insects can be much smaller than 1/4”, sealing the exterior of the house to prevent insect entry is not always very effective, although a logical first step to reduce potential for entry to the home. Certain insecticides/pesticides are readily available and intended for use by homeowners to control/kill insects. In some cases, certain flying insects, such as bees or wasps attempt to build hives in exterior wall cavities by entering through weep holes at the base of brick siding. The weep holes are one of the few locations on the exterior of homes that should not be sealed as they allow building materials behind the brick siding materials to dry properly. Steel wool can often be inserted in the weep holes to prevent insect entry and to allow air to dry building materials.

To reduce potential for termite entry, all “wood pathways” between the soil and the home should be removed on the building exterior. This includes removing wood to earth contact associated with decks/fence posts, wood siding, and all vegetation that may be growing against the home. It is recommended that a qualified contractor be consulted when dealing with wood boring insects because of the specialized and sometimes regulated nature of treatment methods associated with wood boring insects.

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