The federal Indigenous Affairs Department says it needs at least $2 billion to fix 115 First Nations schools that require "immediate attention," according to documents tabled in the House of Commons.

The Liberal government committed half that amount of money over five years in the last budget, and earmarked it for upgrades across the entire school system. The funds will not necessarily be directed toward the schools most in need of repairs — causing some observers to warn there could be a funding crunch that would leave some crucial fixes left unfunded.

The new money is also heavily back-loaded, with nearly 40 per cent pegged to roll out after the next election. There is no guarantee a new government would make the same spending commitments.

The Liberal spending pledge is on top of "base" infrastructure funding, which is pegged at roughly $300 million for each of the next two fiscal years.

NDP MP Charlie Angus said that the department is likely low-balling the price tag.

"These are not educators making funding decisions, they do not come from the education system. These are bean counters in Ottawa," he said in an interview with CBC News. "You cannot trust this department to actually put a serious cost figure on what it will take to ensure safe and comfy schools for children. They've never made it a priority in the past."

About 900 students attend classes at the new school in Pikangikum First Nation, from junior kindergarten to Grade 12. The new school opened nearly 10 years after the last school burned. (Jody Porter/CBC)

While the department recently unveiled a new school in the remote northern Ontario First Nation of Pikangikum — nearly 10 years after their last school burned to the ground — others have not been so lucky, turning to makeshift fixes in the midst of pressing problems.

Barriere Lake First Nation, an Algonquin community in western Quebec, has been battling persistent mould problems at its school for years. An environmental assessment recommended the school be condemned, but the mould was simply painted over.

The problem recently intensified — with the mould becoming very smelly — and the 72 school children had to be moved to four temporary classrooms while they await repairs.

Health and safety deficiencies

The department's warning that it needs $2 billion to make urgent repairs comes after its recently completed inspections of First Nations schools across the country.

It found more than half of the 439 schools surveyed had at least one example of a "health or safety deficiency," according to an order paper question.

A "deficiency" is a term that covers a range of problems from major repairs like crumbling foundations to installing downspouts to prevent flooding.

About 300 students in northern Ontario attend the Aglace Chapman Education Centre in Kitchenuhmaykoosib Inninuwug, originally built in the 1960s. (Jody Porter/CBC)

Some schools are facing a particularly large backlog of deficiencies, notably St. Andrew's Elementary School in Kashechewan in northern Ontario, where 19 infractions have recently been recorded. (The roof has been leaking for years.)

Of all the schools surveyed, 61 per cent are in "good" condition, three per cent are "poor," while the remaining are classified as "fair." Only five "priority" school construction or repair projects were approved in 2015-16, according to the order paper question. There are 515 schools on-reserve, meaning 76 were not inspected in this audit.

Angus said that the standards for First Nations schools are less stringent than those for provincial school systems.

Grading the Gap

CBC News is investigating the quality of First Nations education on- and off-reserve in the wake of the federal Liberal government's pledge to spend $2.6 billion over five years on kindergarten to Grade 12.

Follow our Grading the Gap coverage on CBCNews.ca, CBC Radio One, CBC News Network and The National.

Read stories about students on our interactive page: Grading the Gap

A spokesperson for the department said the government is committed to improving education infrastructure in First Nations communities, and the $969.4-million investment included in the 2016 budget is an important first step.

"An essential component of a student's education is having a safe and healthy place in which to learn," the department said in an emailed statement to CBC News. "The government of Canada is committed to investing in the building and refurbishing of First Nation schools to help improve educational outcomes for First Nation students."

Lapsed funding

The shortage of First Nations education funding is exacerbated by the department's past reliance on moving money out of infrastructure to plug other holes in social spending — or leaving the money off the books entirely.

The former Harper government committed $843.8 million between 2012-13 and 2014-15 for First Nations school infrastructure, with some of that money coming from its Building Canada fund.

But according to the department's order paper response, only $700.6 million actually made it out the door, or roughly 30 per cent less than budgeted.

NDP MP Charlie Angus says the Indigenous Affairs Department can not be trusted to properly fund First Nations education infrastructure because so much money goes unspent each year. (Adrian Wyld/Canadian Press)

"Monies are promised all the time, but the money just isn't spent," Angus said in an interview. "What is really disturbing is that, in any given year, about $100 million is clawed back and spent on other priorities. This is what really speaks to what a non-system it is, what systematic failure looks like."

The financial data for 2015-16 is currently not available.

The difference between planned and actual spending "primarily reflects reallocations to address pressures in other programs, notably social development," bureaucrats explain in the recent order paper question.

This has been a frequent accounting practice in the department since former finance minister Paul Martin imposed a two per cent cap on annual spending increases in the 1990s.

Over the last 10 years, approximately $720 million in First Nations infrastructure money has been reallocated, according to departmental documents obtained by CBC News under Access to Information.

Bureaucrats have long warned that this has made an already dire situation worse.

"While this is helping to cover some of the pressures of social and education programs, it is putting increased pressure on already inadequate infrastructure funding," public servants wrote in a January 2013 briefing note on this issue. "The gap between current identified need and available resources is so vast that even with a significant increase in the escalator, the current gap remains."

"Social, education and infrastructure outcomes for people living on reserve are not comparable to those living off reserve. The gap in outcomes between people on reserve versus off reserve has widened significantly," the bureaucrats said.