When Should Exterior Building Windows be Replaced?

A building’s windows generally require replacement every 25 years. However, this isn’t a hard and fast rule property managers should follow. Here we look at common signs your exterior building windows should be replaced.

Signs of Window Failure

Common signs of window failure include:

Air Leakage

Visible openings where the frames connect with the rest of the building envelope often cause air leaks. Professional testing techniques are the most dependable to identify air leak issues. They use infiltrometer tests that pressurize the building’s interior to spot leaks. Advanced methods include thermographic scans and infrared photography to spot energy escaping through or around the windows and other areas of your building envelope.

Water Leakage

The main cause of water leaks is aging sealants. The urethane sealant – used for windows – is recommended to be replaced 10-15 years. Once it begins to fail the cracks allow water infiltration throughout the entire building. However, expired window gaskets often expire at the same time as the caulking. Original construction commonly used neoprene window gaskets where the glass meets the metal frames on the building exterior. The gaskets wear down with exposure to the elements, contributing to water intrusion. Water intrusion causes costly structural integrity damage. Water can also cause mold and mildew growth and expensive cosmetic damage throughout the building.

Increased Noise Levels

A lesser-known sign of window failure is increasing noise levels. As all the components of the window begin to fail the loss of the insulating properties can no longer muffle outdoor noise.


When condensation, frost, or fog appears between the panes of windows, it indicates inert gas leaks. Also tied to failing seals, contraction due to weather fluctuations can break down the seals containing the inert gas. This allows moisture to get in leading to frost, condensation, and fogging. This is a clear sign the windows are thermally weak which negatively impacts their energy efficiency. Sometimes just the glass unit can be replaced, but in most cases when this happens, it means that the window also needs replacement.

Failing Function

Ongoing use and wear and tear eventually lead to hardware damage. This includes window locks as well as parts such as cranks. Broken hardware poses a security risk as well as prevents egress window access in case of emergency evacuation on lower floors.

When these signs of window failure are overlooked, the ongoing damage and energy waste can lead to tens or even hundreds of thousands of dollars in repairs and energy costs.

Repair or Replace?

Although in some cases window repairs can help prolong the need for costly window replacement, they tend to be bandage solutions. For example, repairing sealants, foam, drainage vents, or water diversion caps to prevent leakage can work on a window to window basis. However, the more time and effort you are putting into the repairs, the more the cost of replacement becomes justified.

At Welldone Inc. we work with high-rise and low-rise condominium buildings, rental apartment buildings, hotels, and commercial buildings replacing building-wide aluminum windows. Our skilled window installers conduct each project with minimal intrusion and disturbance to residents in occupied units. Speak to our team today to learn how we can help with your window replacement project.

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  1. […] panels eventually fail due to age, only the glass itself is replaced. Traditional windows require complete replacement costing more to manufacture and […]