Attic clean-up and prevention

Getting the animal out feels urgent. What it left behind is the part that costs money and, in some cases, affects health. An attic that has held raccoons, squirrels or bats for a season holds droppings and urine, flattened insulation, chewed wiring and sometimes parasites. This page covers cleaning that up and making sure nothing comes back.

The order matters. Clean-up comes after exclusion, never before, because stripping an attic that is still open means paying for it twice. Every quote should read: seal, confirm empty, clean, re-insulate.

Step one: assess and photograph. Not every attic needs stripping. A few weeks of squirrel occupancy in one corner is a spot clean; a raccoon latrine and a season of urine saturation is a full removal. Ask for photographs before agreeing to anything, because full attic restoration is one of the largest line items in this trade and it is not always warranted.

Step two: containment and protection. Raccoon latrines can carry roundworm, dry rodent droppings should never be swept or vacuumed dry, and accumulated bat guano can support the fungus associated with histoplasmosis. That means respiratory protection, coveralls, sealed waste bags and a route out that does not carry contamination through the living space. Hence not a weekend job in a dust mask.

Step three: removal. Soiled insulation comes out, usually with an insulation vacuum running to a truck or sealed bags, and droppings and nesting material go with it. Where contamination is localized, only the affected bays are taken out.

Step four: sanitize and deodorize. Exposed surfaces are treated with a registered disinfectant, and an enzyme treatment deals with urine, which otherwise keeps signalling to the next animal that this is a good den. Smell that lingers after a proper clean usually means something died in a cavity.

Step five: repair what was damaged. Chewed wiring goes to a licensed electrician, and that should not be skipped, since rodent damage to wiring is a genuine fire risk. Crushed ventilation baffles are replaced so the soffit vents still breathe, and damaged vapour barrier and ductwork are repaired while the attic is open.

Step six: re-insulate. New insulation is blown in to the depth the quote specifies, with baffles keeping the soffit vents clear and the attic hatch weatherstripped. This is the efficient moment, and often the one upside of the episode: many Ottawa attics are under-insulated by current standards, so the house ends up warmer than before the raccoon arrived.

Step seven: prevention, which is what stops the next one. The survey covers roof edges and the soffit and fascia junction, roof and gable vents, plumbing stacks and their boots, the roof-to-wall intersection, which is the most commonly missed point on any house, the chimney, and at ground level the gaps under decks, sheds, porches and steps. Materials have to match the animal: heavy galvanized steel mesh or sheet metal screwed into sound wood for raccoons and squirrels, far finer sealing for bats, which use gaps under 15 mm, and buried mesh turned outward in an L shape for skunks. Foam, caulk, plastic and stapled hardware cloth all get defeated. Steel vent guards and a stainless chimney cap are the two highest-value items on most quotes. Ontario's guidance adds the cheapest measure of all, trimming branches near buildings to prevent easy access to roofs and chimneys (Ontario, preventing and managing conflicts with small animals).

How long it takes. A spot clean is a few hours. A full strip, sanitize and re-insulate on an average Ottawa attic is one to three days, and roof prevention work usually a day. Ground-level screening needs unfrozen soil, so it is an April to November job here.

What it costs in Ottawa in 2026. Indicative ranges, matching this site's price guide. Attic clean-up and re-insulation is quoted after inspection and often runs $1,500 to $5,000. Chimney capping or vent screening is about $150 to $400 per opening. The inspection itself is commonly $100 to $250 and often credited to the job. What moves the total: attic size, how much insulation is contaminated, hatch access, roof height and pitch, and how many openings need proofing.

What makes an Ottawa attic different. The older housing stock in the core and the inner suburbs was insulated to standards well below current practice, so a forced strip-out is frequently also an upgrade opportunity worth taking. Ice damming is the local complication: Ottawa roofs carry heavy snow, and an attic that is warm because its insulation has been flattened and its baffles crushed melts snow from underneath and drives water back under the shingles. That is why baffles and hatch sealing are not optional extras here. The three building eras also fail differently: pre-war and post-war houses have wood soffit, knee walls and masonry chimneys with gaps that are hard to seal; the 1970s and 1980s expansion through Nepean, Orleans and early Kanata brought aluminium soffit and plastic roof vents that raccoons and squirrels open readily; newer subdivisions in Barrhaven, Riverside South, Stittsville and Findlay Creek are tighter and tend to fail at vents and roof-wall junctions instead.

Who should do the work, and what to ask. Attic clean-up and exclusion are not licensed trades in Ontario, so judge on liability insurance, WSIB coverage, safe work at height and respiratory protection. Electrical repairs belong to a licensed electrical contractor. Ask: how much of the insulation actually needs removing, and can you show me photographs. What R-value are you blowing back in. Are baffles and the attic hatch included. Will you give me a photographed list of every opening and what you propose for each. What gauge and material, screwed or stapled. What is the warranty, how many years, does it cover re-entry by any animal or only the species I called about, and is it transferable if I sell. A contractor offering a multi-year warranty covering any animal is telling you they trust their own workmanship.