Short answer: spray foam alone is not rodent proofing. Mice chew through it in minutes and rats treat it as a marker for where to dig. Foam has a role, as a finish and an air seal over a metal barrier. The barrier itself has to be something teeth lose to: copper mesh, steel mesh, hardware cloth or sheet metal.
Rodent teeth are harder than foam, wood and most plastics, and gnawing is constant maintenance behavior for them. A foam plug in a pipe gap gives a mouse a soft target exactly where it already wants through, and there is decent evidence rodents chew foam preferentially because it is easy. Hardware stores sell foam with bittering agents and copper particles; those slow a casual chewer and stop nobody determined. If a quote for proofing is mostly cans of foam, it is priced like foam and will last like foam.
The full method, opening by opening, is on the exclusion page.
An inspection names the animal, the scale of the problem and the entry points, with the price for each part in writing.
The honest DIY boundary: a homeowner with copper mesh, a caulk gun and a free Saturday can handle the visible, reachable gaps: under-sink pipe holes, a dryer vent cover, the garage side door sweep. The work that usually needs a professional is the work of finding the rest: the sill line behind a finished basement ceiling, the roofline openings that need a ladder and flashing, the fieldstone joints that need a mason's hand. Our winter proofing guide has the homeowner checklist version, including the order to work in.
A real proofing quote names openings and materials: this gap, this mesh, this joint repointed. A vague one sells a perimeter treatment and a warranty word. Ask which openings are on the list, what each gets sealed with, and whether animals inside are removed first, because sealing a house with mice in it trades the entry problem for a dead-in-the-wall problem. Materials are the cheap part of this work. The finding is the skilled part, and it is what the inspection produces.
Better than foam, worse than copper mesh. Steel wool rusts, and rusted wool crumbles and stains. Packed tight and sealed over, it works as a short-term fill. Copper mesh is the same idea that does not rust out in two winters.
Yes, and useful evidence: a chewed foam plug marks an active route with the animals' own sign on it. It goes on the inspection list as an active entry and gets a metal fix this time.
The metal work does not wear out on a schedule. What changes is the house: freeze-thaw moves masonry, new cables get drilled, door seals tear. A fall look at the sealed points, five minutes with a flashlight, catches the new openings before the mice do.
Call now and tell us what you are seeing. We will walk you through the next step and get an inspection set up.
Sounds in the walls, droppings in the wrong place, a smell that will not air out. The inspection names the animal and the entry points before you spend anything on treatment.
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