There are two different things a pest control company can sell you.
One removes what is currently in the building. The other closes how it got there.
The first is faster, cheaper on the day, and needs doing again. The second takes longer, costs more once, and is the only one that ends the problem. A lot of what is sold in this region is the first, described as though it were the second.
The mouse example, in numbers
A house backing onto a field in Stayner gets mice in October. Two approaches:
Treat only. Bait stations, a follow-up visit, population knocked down. Cost is low. The gap around the gas line entry is exactly as open as it was. Next October the field produces another generation and you make the same call.
Exclude. An inspection finds the gas line entry, a failed dryer vent flap, a settled garage door seal and a gap at the sill plate behind the siding. All four are closed with materials a rodent cannot work through. Cost is perhaps double. The route is gone.
Over five years the second option costs less, and the difference is not marginal. Over the same period the first has also allowed five generations of rodents to contaminate insulation.
What “properly sealed” means
This is where a great deal of exclusion work fails, and it comes down to materials.
| Gap | Wrong | Right |
|---|---|---|
| Around a pipe entry | Expanding foam alone | Packed steel wool or copper mesh, then sealed |
| Chewed corner of a door frame | Filler and paint | Sheet metal kick plate over the repair |
| Failed dryer vent | Tape, or nothing | Rodent-rated vent cover with a working flap |
| Soffit gap | Foam | Hardware cloth, fixed, then closed |
| Under a deck | Lattice | Hardware cloth taken down to grade and turned out |
| Garage door | New rubber seal only | Seal plus building up the settled corners |
The rule is simple: at any point a rodent can get its teeth to, the barrier must be metal or mesh. Foam is an air seal, not a rodent barrier. They chew straight through cured foam and they do it quickly.
A mouse needs roughly 6 mm — the width of a pencil. A young rat needs about 12 mm. That is why a proper inspection takes hours and why the entry is almost never where people expect.
On wildlife, exclusion is not optional — it is the law’s consequence
Ontario’s Fish and Wildlife Conservation Act requires an animal trapped in these circumstances to be released within one kilometre of where it was caught.
Think about what that means. The raccoon you paid to have removed is released within walking distance, knows your building, and the entry point is still open. Trapping without exclusion is not a weak solution. It is not a solution at all.
Anyone offering to take the animal “far away” is describing something they are not permitted to do.
This is also why we will not seal a roof without confirming what is still inside it, and will not exclude a female away from a litter. Both are faster. Both produce a dead animal in a ceiling and a return call.
When treatment is genuinely the right answer
Exclusion is not a universal answer, and it would be dishonest to present it as one. There are problems where the population is the target and the building is not the route.
Wasps in a wall. The sequence is treat, confirm the colony is dead, then seal. Sealing first traps several thousand insects that will look for another exit, which is frequently your ceiling. This is the clearest case where exclusion alone is actively dangerous.
Cluster flies. They enter through gaps far too numerous and too small to seal economically on an older house. What works is a timed exterior residual in early to mid September, before they aggregate. Sealing helps and reduces the numbers; it will not replace the treatment.
Carpenter ants. The parent colony is usually outside in a stump, a dead limb or stacked timber. You cannot exclude your way out of that. You trace it, treat it, and deal with the satellite nest in the structure.
Bed bugs. They arrive on luggage and on people. There is no entry point to close. This is a treatment problem, and the only relevant prevention is inspection between guests.
Ground-nesting wasps at Wasaga. The nest is in the sand. There is nothing to exclude.
The honest summary
| Problem | Primary method |
|---|---|
| Mice and rats | Exclusion, with baiting as support |
| Raccoons and squirrels | Exclusion and entry repair, always |
| Bats | Exclusion only, and only in the legal window |
| Wasps in a structure | Treat, confirm, then seal |
| Cluster flies | Timed exterior treatment, sealing as support |
| Carpenter ants | Treatment, plus fixing the moisture source |
| Bed bugs | Treatment, plus inspection between occupancies |
Half our work is physical and involves no pesticide at all. The other half needs the product and the right month.
What this work costs in Collingwood breaks the numbers down. The question worth asking any company you are considering is not “what will you spray?” It is “what did you find, and what are you doing about how it got in?” If the answer to the second half is nothing, you are buying a season.