The Municipality of Anchorage has issued a warning to more than 1,000 commercial building owners who may have potentially hazardous roof construction that could collapse under heavy snow load. The warning comes after six roofs have failed in Anchorage this winter, including two on Sunday.
The warning letter, which was sent by the Municipal Building Department last week, identifies the type of roof construction that is prone to failure as flat roofs with wooden trusses and metal gang nail plates. These are metal plates that connect the wooden trusses at the joints, and are often used in older buildings.
According to the letter, these metal plates can corrode over time and lose their strength, especially if they are exposed to moisture or salt. The letter also states that the snow load on the roofs can exceed the design capacity of the trusses and the plates, causing them to fail and collapse.
The letter instructs the building owners to take immediate action if they have this type of roof construction, such as:
- Removing the snow load from the roofs as soon as possible, using qualified contractors or engineers.
- Inspecting the roofs for signs of damage or distress, such as sagging, cracking, or leaking.
- Consulting with a licensed structural engineer to evaluate the condition and capacity of the roofs, and to make any necessary repairs or upgrades.
The letter also advises the building owners to contact the Municipal Building Department if they have any questions or concerns, or if they need assistance in finding qualified professionals.
The examples of roof failures
The letter cites six examples of roof failures in Anchorage this winter that have involved this type of roof construction, including two that occurred on Sunday. The first one was at the Alaska Mill and Feed store on 1st Avenue, where a section of the roof collapsed around 9 a.m., causing damage to the building and the merchandise. No one was injured in the incident.
The second one was at the Alaska Native Heritage Center on Heritage Center Drive, where a portion of the roof over the theater collapsed around 11 a.m., causing water damage to the building and the equipment. No one was inside the theater at the time of the collapse.
The other four examples of roof failures that have occurred this winter are:
- The roof of the Alaska Club East on Tudor Road, which collapsed on Jan. 18, injuring one person and damaging the pool and the gym.
- The roof of the Alaska Railroad Corporation warehouse on Post Road, which collapsed on Jan. 19, damaging the building and the vehicles inside.
- The roof of the Alaska State Troopers hangar on Merrill Field Drive, which collapsed on Jan. 20, damaging the building and the aircraft inside.
- The roof of the Alaska Native Tribal Health Consortium warehouse on Tudor Centre Drive, which collapsed on Jan. 21, damaging the building and the medical supplies inside.
The response of the building owners
The warning letter has prompted some building owners to take action and remove the snow from their roofs, or to hire contractors or engineers to do so. Some of them have also contacted the Municipal Building Department to report their status or to request more information.
However, some building owners have expressed frustration or confusion over the letter, saying that they are not sure if their roofs are at risk or not, or that they are not able to find qualified professionals to help them. Some of them have also questioned the timing and the tone of the letter, saying that it is too late or too alarming.
The Municipal Building Department has said that it is trying to reach out to as many building owners as possible, and that it is available to answer any questions or concerns. The department has also said that it is working with the state and the federal agencies to provide more resources and guidance to the building owners, and that it is planning to hold a public meeting soon to address the issue.