Headwaters Apartments, a city-owned complex erected in 2007 in Southwest Portland, gave every resident of the top floor three days to get out after the roof showed signs of failing.

"The roof's condition combined with potential winter snowfall may create an unsafe situation," reads a Nov. 24 letter given to Headwaters residents at a meeting to inform them of the problem. "We are very sorry this is happening to you, and this has to happen to you so quickly." (The residents had to be out by Nov. 27.)

The 100-unit building in Multnomah Village cost $14.7 million to provide high-quality, environmentally sustainable housing for tenants making no more than median income.

Renters from the 22 occupied top-floor units were offered help by building managers to find an Airbnb or hotel, in a letter from the complex. "Costs associated with moving will be covered by the owner of the property," the Nov. 24 letter states.

The letter estimates it will take nine to 11 months to fix the roof.

Portland Housing Bureau spokeswoman Martha Calhoon say they don't know yet what caused the roof problems.

"Structural engineers advised swift precautionary action," adds Calhoon, who says the city does not yet have an estimate of how much it will cost the city.