By: Bill Davis
August 31st, 2021
Currently, much of the world is working from home due to COVID-19. Some people enjoy the remote work, and some can’t wait to get back to the office, especially if they live in an apartment with no outdoor space to enjoy the rest of the summer. For some New York City apartment owners, the idea of sprucing up their balcony by installing tile over the slab sounds like a simple way to make an outdoor area more appealing. However, it is the opposite; in most cases, this seemingly trivial renovation can be detrimental to the building. It is imperative to consult a professional before performing balcony renovations in order to avoid creating unsafe conditions or potentially compounding existing ones.
If tiles or pavers are installed on the balcony slab incorrectly by a non-expert, there can be extreme damage to the building envelope with significant ramifications, such as UNSAFE façade inspection safety program (FISP) filings, costly repairs, as well as the requirement to install a sidewalk bridge to protect the public, which can be costly.
When tiles are improperly installed on the slab of a balcony, moisture can become trapped between the tile and the concrete. That trapped moisture will go through freeze/thaw cycles in the winter and cause extensive deterioration to the underlying slab and damage the structural integrity of the balcony.
Unbeknownst to most, railing post penetrations are typically a weak point in balcony systems. These penetrations require careful attention and proper treatment to prevent rust jacking, concrete spalling, and other various unsafe conditions. Some red flags to look out for on balconies with an existing tile finish include efflorescence and organic growth at the tile joints and the balcony perimeters, a lack of drip edges and flashing, ponding water and staining, and cracked tile. All of the aforementioned conditions are indicative of and conducive to allowing trapped water beneath the balcony finish and require immediate attention. The longer these conditions are left in disrepair, the more costly the repairs; this is often the case where conditions are exacerbated by the additional structural load of the tile system.
Balconies with a tile finish require a positive pitch for proper drainage, which was often overlooked when older buildings were constructed in New York City. In addition to the typical setting bed, exterior grade tile, and proper joints, a good waterproofing membrane and drainage system are a necessity for an effective, functional and durable system. Before a waterproofing membrane is installed below the tile system, proper preparation of the existing slab is paramount. The concrete should be inspected and sounded carefully by a professional to identify any deficiencies, such as cracks, spalls, and exposed or deteriorated reinforcing bar. All hazardous conditions must be properly repaired and addressed prior the installation of tile. It is also necessary to test concrete for integrity as well as to ensure that there is adequate structural support and steel reinforcement to add additional weight to an existing balcony.
Aside from the deleterious conditions that can be caused by the improper installation of tiles, balconies are designed to hold a specific weight. The dead load of a structure includes the weight of the concrete slab, railings, and any other permanently fixed materials, like pavers and tile systems. Live loads consist of any temporary or transient weights, such as people, furniture, and any items not permanently fixed. Over time, the additional weight of the tiles will contribute to long-term deflection or displacement and can cause structural movement that leads to improper water drainage and cracks in the concrete.
Sullivan Engineering A Rimkus Company specializes in analyzing balcony conditions, waterproofing systems, and balcony repairs. If you are tempted to turn your outdoor space into an improved oasis, we urge you to consult with an expert first; no balcony is worth putting others in harm’s way. For detailed information on common balcony conditions, repairs, and maintenance, please take a look at Jimmy Monahan’s 2-part article series: “Balcony Conditions and Their Causes” and “The Importance of Maintaining Balconies.”