Two days after CBC News reported on the potential danger of decaying stained-glass windows in the House of Commons, repairs on some of those windows are beginning.

On Wednesday, CBC News revealed an internal government report warned crumbling brickwork and loose window glass pose a "potentially catastrophic," life-threatening risk to members of Parliament and others.

The danger isn't just hypothetical. In 2012, workers found a heavy piece of glass that had apparently plummeted to the Commons floor overnight when no one was around. The panel was from one of 12 tall stained glass windows installed in the early 1970s.

On Friday, an email went out to House of Commons staff informing them "preliminary work" would be done to repair three windows in the west gallery — those depicting scenes from Saskatchewan, Alberta and British Columbia.

The work is scheduled to begin Friday and continue through Oct 19.

A spokeswoman for Public Works said the repairs have been in the works for weeks, and had been planned to coincide with the Commons' Thanksgiving break next week.

"We are now proceeding to address the next set of windows and doing the work during the Thanksgiving break week," Annie Trepanier wrote in an email to CBC News.

Trepanier‎ explained that the work involves creating stencils of the existing windows and laminating them to temporary glass windows that will be installed while the originals are repaired.

Public Works told CBC News earlier this week that workers had already removed the three most dangerous windows, and were monitoring the nine others that line the Commons chamber.

The internal report also warned of loose bricks in the roof area of the Commons foyer, just outside the chamber, that could fall on people. The email to staff makes no mention of plans to repair it.

'A lot of neglect': Mulcair

CBC News learned of the problems in a 177-page internal report written last year and obtained under the Access to Information Act. It found the 12 stained-glass windows were improperly installed in the Commons chamber.

An internal report for Public Works also warned loose bricks in the roof of the Commons foyer could crash through the decorative glass ceiling, injuring people standing below. (Julie Van Dusen/CBC)

Water damage and poorly fitted framing has since loosened the glass as well as the surrounding bricks and stonework.

NDP Leader Tom Mulcair expressed concern about the report's findings.

"When you walk through the corridors upstairs, you can see lots of water damage, you can see things that are simply not taken care of," Mulcair said Wednesday following a caucus meeting in the Centre Block of Parliament Hill, where the Commons is located.

"I don't want to take anything away from the amazing women and men who work here every day. There's a huge team that keeps our Parliament functioning.

"But it's quite clear to anyone who takes the trouble to look around that there's been a lot of neglect. There's been a lot of neglect in some of our heritage buildings in Canada. That's a sad fact."

Public Works responded to CBC's initial report by saying it had already carried out the most pressing repairs and was closely monitoring any remaining problems to guard against any health and safety risks.