A U.S. Centers for Disease Control report released earlier this month focused on a case in Quebec where 14 people fell ill with a pneumonia-like infection after the exterior brick of a century-old house was removed as part of a renovation.
Workers, residents of the home and neighbours have recovered after developing symptoms of a fungal disease called histoplasmosis, which is carried in the droppings of bats and birds. Infection symptoms include high fever, coughing, chest pain and shortness of breath.
Cases of histoplasmosis infection are rare in Canada and usually involve construction work that stirs up clouds of dried-up aerosolized spores that people end up inhaling. In the Quebec case, workers had been given masks to wear but didn't do so continuously due to hot weather.
Whether homeowners are embarking on a do-it-yourself project or enlisting a professional, here are tips from experts for making health and safety a top priority throughout the home renovation process.
— Conduct a thorough assessment.
Cory Norris, chief project estimator at Greater Toronto Contractors, said the No. 1 determining factor as to whether there will be problems with the home is its age. They also look at the state of the home, with visible damage among the red flags.
"If you can see water damage, if paint is peeling off walls here and there ... if it hasn't been maintained well, they probably have ignored any kind of problems that have been going on as well: rodents, bats, for example, mice ..."
Norris said workers will go into the attic and lift up some insulation where mice, rodents and squirrels "love to make their home."
While a few droppings aren't a cause for concern, discovering a significant amount is problematic and requires expert attention. "I stop, I come out and then I tell the homeowner, 'We should have this stuff tested,'" Norris said.
"If I go into the home and see the old paper-type wrapping around plumbing pipes, we say: 'Don't touch a thing here; we have to get this tested for asbestos.' Any home that's been built pre-'80s, there's going to be a real high chance that there's asbestos somewhere," he added.
"Lead in the paint is another one. If there's 20 layers of paint on the walls, and that house is 80 years old, you just can't tear that stuff down without proper respiratory masks."
Homeowners should also ensure the roof is in good condition, said Jon-Carlos Tsilfidis, president of Toronto-based Fairside Homes.
"A roof like anything else needs to breathe — otherwise you're going to get condensation in the roof and that's going to cause all kinds of other problems," said Tsilfidis, a member of the Building Industry and Land Development Association.
"So make sure that your soffits are vented and unobstructed. Make sure you have enough breathers in the roof, depending on the size of your roof, and make sure there's enough insulation."
— Got mould? Follow your nose.
"Mould needs heat, it needs food and it needs moisture. If there has been a flood in the house, there's a pretty high probability that there's going to be mould there," said Gary Sharp, director of technical services, Canadian Home Builders' Association.
"If they're cleaning up after some kind of a water event, they should take precautions. Assume that there's mould there until you've proven to yourself that there isn't."
Sharp said there is a musky odour typically associated with mould.
Tsilfidis said most people can usually detect when there's water coming into the basement by the mouldy smell, and can also observe it at the bottom of drywall.
"It starts to discolour, it starts to get black and green. Just cut the piece of drywall ... a little bigger than the affected area and just see what's happening," he said. "Make sure that you're treating your wood studs in behind that as well. Open up a bigger area than you need to to ensure that the mould hasn't spread."
Sharp said it's certainly possible for homeowners to take care of mould, but it's recommended to bring in a professional to handle the job — particularly if the mould is significant.
— Gear up.
"Obviously, if you're going to be removing walls, you're going to have drywall dust, maybe plaster dust depending on the age of the house, and you're going to need to make sure that you have the right protective equipment," said Sharp.
In addition to proper gloves, tools and footwear, Sharp said eye protection is also important, especially during the demolition phase. Masks carried at home supply stores are typically labelled for the types of protection they offer, he noted.
"The really simple ones are the ones that just go over your nose and mouth and they have a little pinch piece that goes over the nose, and that's really just a dust mask."
Norris said respirators are usually used more for industrial applications. A tight-fitting dusk mask will be what most work crews use, he noted.
— Seal off the space.
Sharp said renovators will generally seal off the room to create a barrier to help prevent dust from permeating the house. This could involve using polyethylene which comes in a sheet or roll to cover openings, he noted.
Norris said they always work to ensure that everything is sealed off in the other parts of the home — especially the ventilation system. "If we're only working on one particular part of the home, we make sure those registers are sealed off and any doors are sealed off."
— Keep the space clean.
Despite best efforts to cordon off an area, fine dust particles will always find a way to seep through, said Tsilfidis. This is why people need to be proactive in wiping down and cleaning as much as possible.
"We do that as a matter of course on a daily basis. But again, you can't catch all of the dust in the air," Tsilfidis said. "That's why usually when we do ... larger-scale renovations, people move out."
Using damp rags and a shop vacuum, which ingests both wet and dry debris, will handle the majority of the dust — but "sweeping is futile," said Norris.
"Trying to sweep up a construction site during the finishing phases, you're just pushing the dust around. It's going to get on the walls, on the ceiling," he said.
"Even after a construction project, you'll have to take a damp cloth and wipe down the walls. Even if they've been freshly painted, I'd wipe down the walls, wipe down the ceiling."
— With files from Sheryl Ubelacker