Case Study

Exterior Building Leaks

TUCKPOINTING GONE WRONG

The Problem

While brick exterior walls of a building appear to be waterproof, in fact, they are quite porous and function as one of many building systems to keep interior spaces dry. They require periodic maintenance, including tuckpointing, caulking, and sealing. A routine tuckpointing project was set in motion.

Action Taken

In a 6-story section of the tuckpointing project, I observed a pending failure that might have injured the crew erecting the scaffolding. The brick ties—connecting the wall of bricks to the inner wall structure—had corroded and the brick was bowing outward, soon to fall. I called out to the crew to leave immediately. A 30’ x 25’ section of brick on the 4th and 5th floors fell just as they had walked away.

Outcome

Everyone was safe. The brick ties were replaced as the brick was reset. The leak at the roof curb was repaired pending a full replacement.

Summary

A building’s brick façade appears to be waterproof. It isn’t. In fact, it’s quite porous, and water will find its way toward the interior. But its protective function and structural strength are dependent upon the building envelope’s design detail, and, importantly, a maintenance schedule to keep it in top shape. This is especially true when a building is multiple decades old.

When private owner spaces experience external leaks, it’s important to understand that building envelope materials and systems are integrated. Too frequently, the “cause of the leak” is mistakenly found to be ONLY cause. Often, other components are part of the problem. Buildings are holistic systems. Roofing systems; scuppers, gutters, and downspouts; flashing at key interfaces; tuckpointing and sealing of the brick face; and ultimately how effective the water is moved away from the building must integrate to keep a building dry.

In a phased set of projects targeting multiple building envelope repairs over several years—including the full replacement of over 12,000 square feet of ground level garage deck, and the replacement of flashing at a “soldier course” and ground level—the next phased work was tuckpointing, repairing cracks in the grouting on nearly 700 lineal feet of a 6-story condo.

The tuckpointing proceeded well until I observed a 30’ x 25’ section of brick at the 5th and 4th floors begin to bow outward. The tuckpointing crew was up and down the scaffolding section at that location and was too close to see the pending collapse of the brick. I called out to the crew to quickly move away from the wall section, which then collapsed in less than 2 minutes from my warning to the crew. Thankfully, no one was hurt.

The origination of the failure occurred at the top of the wall, where old and missing caulking at the curb edge allowed excessive water to cascade down the inside of the brick face, which over time corroded numerous brick ties connecting the bricks to the framework underneath.

Lessons Learned
  • Worker safety must be a key aspect of every construction project plan.
  • Maintenance extends service life and prevents failure.

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