Every April we get the same calls from Wasaga Beach and from the escarpment: somebody has opened a property closed since October and found six months of undisturbed occupation.
Those are consistently the worst infestations of our year, and almost all of them were preventable in August.
Why an empty building is the ideal building
Think about what a rodent wants: warmth, quiet, food, and nothing that disturbs it.
A seasonal property left on low heat provides three of those outright, and the fourth — being left alone — is the one that matters most. In an occupied house, a mouse population is under constant low-level disturbance. Somebody opens a cupboard, moves a box, turns on a light. It suppresses the population and, more usefully, you notice it early.
An empty building offers none of that. A pair of mice arriving in October have until April with nobody in the way. What you find in spring is not what moved in. It is several generations of it, plus contaminated insulation, plus whatever they have chewed.
The timing is the whole point
The autumn move indoors is driven by the first hard cold nights and, on the rural side, by the fields being cut — the population loses cover and food at the same moment and heads for the nearest heated structure.
That means the sequence matters:
Exclusion in August or September — you close the routes before the move happens. The building goes into winter sealed.
Exclusion in April — you close the routes after a winter of occupation. You are now also paying for droppings remediation, possibly insulation, and whatever has been chewed.
This is why exclusion beats spraying on a seasonal property. The work is identical. The bill is not, and the difference is usually several times the cost of the exclusion itself.
What to do before you close
Get the mouse and rat exclusion done. Service penetrations, dryer and bath vents, the garage door seal and its corners, the sill plate behind the siding, and anywhere a deck meets the building. Metal or mesh at any point they can get their teeth to — expanding foam on its own is chewed through in weeks.
Remove everything edible. Not just the obvious food. Pet food, birdseed, candles, soap, and anything paper or fabric they will nest in. A cardboard box of linen is bedding.
Leave monitoring in place. Snap traps or monitors in the places rodents actually travel — along walls, behind appliances, in the utility space. The point is not primarily to kill anything. It is so that when you arrive in April you learn what happened rather than guessing.
Deal with the exterior. Move the woodpile off the wall and up off the ground. Cut back branches touching the roof; they are a bridge. Clear leaf litter from against the foundation.
Check the roofline while you can still get up there. If there are bats in it, the exclusion window closes at the end of August too. On the escarpment properties this is the one that gets skipped. A gap at a roof–soffit intersection admits a raccoon, and nobody is going to hear it happen between November and April.
The Wasaga variation
A large share of housing here began as seasonal cottage and became year-round accommodation in stages, built by different people at different times. Those buildings have more junctions, more mismatched additions and more unsealed penetrations than anything purpose-built.
If that describes your property, the exclusion inspection genuinely takes longer than the square footage suggests, and it is worth booking rather than fitting into the last weekend before you close.
If you are reading this in April
Then the order is different: find out what is in there before you clean anything.
Do not sweep or vacuum dry rodent droppings in an enclosed space. Ventilate first, wet the material down, and wear a proper mask rather than a dust mask. And do the exclusion now anyway — the routes that let them in last October are still open, and August is only ten weeks away.