Telegraph photo by DEAN SHALHOUP A police cruiser is parked on one side of the closed-off sidewalk and one travel lane in front of 243-247 Main St. this week. Tenants of the upstairs apartments are expected to be able to return within a day or two.

By DEAN SHALHOUP

Senior Staff Writer

NASHUA – The collapse of sections of the brick veneer from the front of the large apartment/retail building at 243-247 Main St. over Labor Day weekend was caused by the failure of steel ties that corroded over time, a building official said Wednesday.

Bill McKinney, the manager of the city’s Building Safety Department, said the ties, which support the brick veneer fascia, deteriorated due to corrosion caused by moisture interacting with the mortar that holds the bricks in place.

The upside is that the collapse didn’t affect the structural integrity of the building, and the reason the tenants have been displaced for several days is that one of the building’s two exits is closed off due to concerns that more bricks may fall without warning.

McKinney said that because the building lacks a sprinkler system, it is required to have two exits, which officials refer to as “means of egress.”

He said he expects to receive the results of an assessment report by today, and “once we’re confident people can use that second exit we’ll be able to open the sidewalk and allow tenants to return.”

Officials will likely arrange for a “tunnel” to be erected along the sidewalk in front of the building, which would shield pedestrians from any falling materials as crews work on repairs.

The assessment report will also determine the size of the area affected, McKinney said, adding that the entire front of the building will be inspected.

Covering wood-frame buildings with brick veneer to protect the wood was common some 100-125 years ago, when 243-247 Main St., and its adjacent neighbor 235-241 Main St., were built, McKinney said.

Both properties, along with another parcel at 10 West Hollis St., are owned by MWH Holdings LLC, according to city property records. The firm’s office address is 253 Main St.

Each is estimated to be around 120-130 years old, according to assessment cards.

Dean Shalhoup may be reached at 594-1256 or dshalhoup@nashuatelegraph.com.