CO-OP / CONDO BALCONY REPAIR

If most of your co-op's balconies are in the condition you describe, the co-op board will probably have to bite the bullet and undertake a full-scale balcony-repair program. The defects you note are significant, especially if widespread. Cracks allow water to penetrate the concrete, further damaging it and the reinforcing steel beneath. As the water freezes in cold weather, the ice expands and creates more cracks, allowing more water to enter and causing more cracks and more water penetration.

The "icicles" are stalactites — calcium carbonate deposits similar to those in caves. They form as water drips from the balcony slab, drawing out the calcareous materials used in concrete. Stalactites are a sign of substantial, longstanding water penetration.

Cracks allow water to penetrate

the concrete, further damaging it

and the reinforcing steel beneath.

Your co-op's loose railings, which are a safety hazard as well as a code violation, are also a result of water infiltration. If the spaces where the railing posts penetrate the concrete are not properly caulked, or the caulking has deteriorated, water seeps in and eventually rusts the posts. As the metal oxidizes, the rust on the post accumulates and pushes against the surrounding concrete, loosening the posts from their footings and creating additional cracks, allowing more water to enter and further loosening the posts.

Balcony Survey

To determine how extensive the deterioration is throughout the balconies and what types of repairs are necessary, the first step is to hire a qualified engineer or architect to conduct a thorough survey. Working from a scaffold to fully access all the balcony areas, the engineer / architect will select an apartment line with balconies that show obvious signs of deterioration. Using a mallet to sound out the concrete, the engineer / architect determines the most badly damaged areas and whether the balconies are structurally sound.

As part of the survey, the engineer / architect may request investigative probes of the concrete (conducted by a contractor) to determine underlying conditions. In some cases, a core sample —  a roughly four-inch-wide circular cut through the entire thickness of the concrete —  needs to be taken. It's tested to determine the extent of damage through the entire thickness of the concrete slab. Probes also determine if the steel reinforcement is rusted, which could lead to structural weakness.

Based on the survey findings, the engineer / architect will recommend whether your co-op needs a full-scale repair program or if limited repairs will suffice. In your co-op's case, a balcony-repair program would probably entail extensive concrete repairs and new railings. If the balconies are extremely damaged, they may need to be demolished and rebuilt

Concrete Repairs

While financially strapped co-op / condo boards may be tempted to hire a contractor to make spot repairs such as patching and caulking, the underlying deterioration in the concrete will remain and only grow worse.

After the concrete repairs are made, a non-slip traffic-bearing coating system should be applied to the balcony floor and curb surfaces. A non-permeable coating system is applied to the balcony fascia surfaces, while a permeable coating is applied to the underside so the surface can breathe and allow water vapor transmission.

Ironically, sometimes repairing the concrete balcony floors and applying a coating system actually increases water ponding on the floors. The paradox is caused by two factors.

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