The ongoing mould crisis in Canada's First Nation communities stems from how construction materials are being shipped and stored, according to multiple experts with first-hand knowledge.

Drywall is transported to remote communities on ice roads and then left outdoors for months, making the material mouldy before the construction of a new house begins.

"Even before you drive a nail, you're fighting a losing battle, because of a lack of quality control and a lack of industry standards," said Alan Isfeld, a carpenter from Waywayseecappo First Nation.

Many northern Indigenous communities rely on ice roads to transport all the building supplies they need for the entire year.

"In the spring, winter roads start to get softer, and the big rush is on to get this material up north," Isfeld said.

Alan Isfeld, a carpenter who helped build houses on-reserve for decades, says supplies are exposed to mould even before the first nail goes into a new home. (Marina von Stackelberg/CBC)

But many of the materials sent by truck are not properly protected for those kinds of conditions, Isfeld said.

"You've got water splashing on the materials," he said.

"Once they arrive, these building materials are left outside for the most part, sitting on the ground or on pallets. Moisture gets inside and condenses and the mould has started already," Isfeld said.

Isfeld said this problem is longstanding and widespread across the country — he built homes on-reserve for decades, and sold building materials to remote First Nations in northwestern Ontario.

Housing on-reserve not subject to same regulations

Houses built on-reserve are not subject to the same rules and regulations as those in the rest of Canada.

"Local chiefs and councils have the authority to create bylaws to adopt provincial or national fire and building codes for on-reserve infrastructure," Indigenous Services spokesperson William Olscamp wrote to CBC News.

Each local First Nation oversees the shipping, storage, construction and maintenance of new homes, with financial and advisory support from the federal government.

"[Indigenous Services] is the owner, and then they put the onus on the backs of the different chiefs and councils, who are not professionals, when it comes to building homes," Isfeld said.

"So you have a lot of people building homes that aren't qualified," he said.

Enough to build 2 or 3 homes per year

The federal government has allocated $600 million over three years to improve housing on-reserve.

That means each community would receive an average of $323,625 per year for all their housing needs, including repairs and new construction.

The chief of one remote Manitoba First Nation said that's not a lot of money to tackle the housing crisis in his community, where 100 homes are needed.

Joe Antsanen, chief of Northlands Denesuline First Nation, said of the homes that do exist, 40 of them have severe mould problems, causing major respiratory issues for many people.

"We have a high rate of mould in our communities. We're trying to keep up with the repairs and so forth, but it seems like we can never put an end to it due to our lack of funding," he said.

A home on the Wasagamack First Nation, about 600 kilometres north of Winnipeg in northern Manitoba. (Karen Pauls/CBC)

Antsanen said his reserve of 1,000 people has received the same amount of funding for all their housing needs since the 1980s: $542,000 a year.

That's barely enough to build two or three homes a year, he said.

In order to make those dollars stretch, his community relies on shipping the materials on the winter roads, which is cheaper than flying them in, but puts them at risk of damage.

Antsanen said many northern First Nations also have nowhere to store their building materials. His community pushed for the funding for a warehouse to store their supplies, but they often run out of room.

"Sometimes we have to put it outside and just cover it with tarps," he said. "This is where the water and the moisture gets to it and shortens the life on the new homes that we build."

Crowded conditions promote mould

Most new homes usually only last six years, he said.

That's in part because the damaged building materials can't withstand the environment, but also because the housing shortage forces more people to live in one house, which promotes humidity that speeds up mould growth.

"A three bedroom [home] will have 14-16 people living in it," Antsanen said. "They live in the living room. They sleep in the hallway.… When it's time for kids to go to bed, you've got to move the kitchen table aside to put a mattress there to sleep on that."

The interior of a residence in Cat Lake First Nation is seen on Feb. 5. (Submitted by Charlie Angus)

Indigenous Services said it is working with First Nations partners to improve data collection and monitoring and to ensure housing projects funded by the federal government are built according to the National Building Code of Canada.

It's estimated that it could cost $9 billion to close the housing gap for First Nations on-reserve, according to Indigenous Services.

Across the country, there is a demand for 41,000 new homes on-reserve, plus major repairs to an additional 44,000 existing homes.

Drywall 'a growth medium' for mould

Even if the building supplies look OK, they're likely still damaged from being exposed to water during shipment or storage, according to a mould expert at the University of Manitoba.

"There are definitely fungi there. There are leaves — everything — that could create mould there. So when it heats up and is brought inside, it's bringing the mould spores in with them," Shirley Thompson said.

"This is not where Home Hardware, or Canadian Tire, or any of these building supply stores would … store their materials," she said.

Shirley Thompson is working with two northern First Nations in Manitoba to design and build homes that are more resistant to mould. She says the issue of mouldy building supplies is widespread across all remote First Nations communities in the province. (Tyson Koschik/CBC)

"Drywall is a growth medium for mould. There's cellulose in that material, and that cellulose is food for fungi," she said.

"They may not get mould growing, and you may not see it when you bring it in, but it's got the spores."

Thompson heads up a new program that aims to eliminate the need to ship and use drywall in the first place.

She's currently working on a pilot project to train community members in Wasagamack and Garden Hill First Nation to build mould-resistant homes using local wood.

Quantity versus quality

Continuing to build houses in remote communities the same way they have in the past will not solve the problem, according to Indigenous architect Douglas Cardinal.

"If you continue on like this, you're always going to get unhealthy buildings with mould," said Cardinal, who designed Canada's Museum of History in Ottawa and Thunderbird House in Winnipeg.

"Drywall is too fragile. You can break it easy, and it absorbs moisture. It doesn't become drywall. It becomes wet wall," he said.

"To build a better house will cost a little bit more, and they say, 'Well, we can't do that. We would rather build more crummy houses,'" he said.

"It's like baking a cake. You don't come with the wrong ingredients and expect a good result."