The attached garage is the front door
If you want to know how mice got into a Minnesota house, start in the garage. Almost every home built in the last sixty years has one attached to the living space, and it fails as a barrier in a very consistent way. The overhead door has a rubber bottom seal that flattens, cracks and pulls away at the corners, usually within a few winters. Those corner gaps are far wider than a quarter inch, and they sit at ground level where a mouse is already traveling. Once inside, the animal finds exactly what it wants: birdseed, grass seed, dog food in a paper sack, cardboard for nesting, and a warm shared wall. From the garage, the route into the house is short. The wall between garage and living space carries plumbing, wiring and duct penetrations, and the seal around the service door frame is often incomplete. Mice follow those openings into a wall cavity and go where they like. Fixing this is cheap compared with the rest of a rodent job. Replace the bottom seal, add corner blocks, weatherstrip the service door, screen the wall penetrations with metal, and get the food into hard containers. That one afternoon prevents a lot of winters.
A month-by-month rodent timeline for a cold state
April and May are the thaw window. Outdoor food returns, breeding resumes, and animals that spent winter in a wall start moving in both directions. It is the best time of year to seal, since populations are near their annual low and the exterior is finally workable. June through August is the invisible build. With highs around 83F and humidity near 70 percent, cover and food are abundant outdoors and numbers climb where nobody is looking. Complaints in these months come mostly from sheds, garages and detached buildings. September through November is the migration. Nights cool quickly, outdoor resources collapse, and animals test the building line looking for warmth. Nearly every infestation people describe in January began during these three months. December through March is the loud, contained phase. Everything is inside, moving through walls and attics toward heat, and snow gives cover right up to the foundation. Trapping is effective, but exterior sealing on frozen ground under drifts is slow and sometimes has to wait for spring, which means many Minnesota jobs run as trap now, seal in April.
What a serious inspection finds in a Minnesota house
Expect an hour or more and a written map rather than a quick price. Outside, the inspector should be low along the whole perimeter, checking the garage door seal and its corners, the service door threshold, hose bib and gas line penetrations, dryer vents that no longer close, window wells without screening, deck and stoop skirting, and any burrow openings at the foundation edge. Then upward: soffit returns, roof junctions, gable vents and the chimney. Inside, the basement or crawlspace tells most of the story. The sill plate seam, joist pockets, floor drains, pipe chases and the electrical service entry are the usual finds. In the attic, insulation is read like a page: runways pressed flat, latrine areas, chewed cable jacketing, and nests tucked at the eaves. What you should receive at the end is a photographed list of openings, an assessment of species and how long the activity has been going, and a scope that splits trapping, sealing and cleanup into separate lines. Without that split, comparing two companies is guesswork.
What makes one rodent quote bigger than another
The honest answer to what this costs is that it depends on the building, which is why an inspection comes first. Several things drive it. How far activity has spread is the biggest factor. One cabinet in one kitchen is a small job; droppings in the garage, basement and attic means three separate zones to trap and check. Next is the number of entry points and how accessible they are, since ten gaps in siding is a very different day than ten in a stone basement wall or behind finished drywall. Cleanup is the line item people forget. Removing soiled attic insulation, disinfecting and re-insulating is its own project, and on a home worth around the state's median of $320,000 that work can be a significant share of the total, so ask whether it is included or separate. Then look at how many follow-up visits are built in. Finally, read the warranty on the exclusion carefully. Its length and its exclusions vary far more between companies than the sealing price does.
Cabins, sheds and the spring cleanup problem
Buildings that sit closed for months are a separate rodent category, and Minnesota has a lot of them: lake cabins, hunting shacks, detached shops and garden sheds that nobody opens from November to April. What happens inside is predictable. An unheated, unvisited building offers cover and quiet, so rodents nest freely in mattresses, cushions, stored gear and insulation. By spring the accumulation of droppings and urine can be substantial, and the first person through the door usually reaches for a broom, which is exactly the wrong tool. The CDC approach is to open windows and doors and leave the building for 30 minutes before entering, then wet everything down with a bleach solution of about 1.5 cups per gallon, let it soak five minutes, and wipe it up with towels that go into a sealed bag. Wear gloves. Do not sweep and do not vacuum, since dry material puts particles into the air in a small enclosed space. After cleanup, seal the building the same way you would a house, and store cushions and bedding in hard-sided totes rather than leaving them out.
Reading two proposals side by side
When you have two quotes in hand, put the totals aside for a few minutes and compare what each one actually buys. The cheaper one is usually cheaper because it stops at trapping. Work through five questions with both companies. Which openings did you find, and can I see the photographs? What material will close each, since hardware cloth, sheet metal and mortar survive gnawing while foam alone often does not? How many visits are included, and what is the plan if activity continues past them? Is cleanup or insulation replacement in this number? What does the exclusion warranty cover, for how long, and what cancels it? One more question sorts them quickly: if I hear activity again two months after you finish, what happens, and what does it cost me? A company that seals thoroughly has a straightforward answer, and one selling a route will hedge. Take the written scopes home and read them line against line. a rodent problem that has been building since fall can wait two days for a second opinion.