In the early hours of the morning, on June 24, 2021, Champlain Towers South in Surfside, Florida, suffered a collapse of the east wing, killing 98 people.

The 136-unit condominium, at 8777 Collins Avenue, was constructed in 1981. Most of the building was 12 storeys, with a last-minute 13th-floor penthouse added on the east side. The tower sat over a single-storey garage, the roof of which served as the pool deck. This pool deck was contiguous with the ground floor of the tower.

Building failures of this horrific scope are seldom seen in North America. But it is important to examine what happened so we can learn and prevent similar collapses in the future.

Anecdotal evidence from the scene allows us to recreate the sequence of events. About five minutes before the east wing of the tower collapsed, a large portion of the pool deck collapsed. Video evidence taken at the time, looking down the garage entrance ramp, showed concrete debris on the floor of the garage, and a sprinkler pipe in the garage sheared off and spraying water.

A unit owner was in the lobby and noted that the cars in the ground-floor parking lot outside the window had fallen into the parking garage below. A unit owner on the sixth floor, who went on to perish in the collapse, was on the phone with her husband at the time and reported a “sinkhole” in the pool deck.

Tragic triggers

Why would the collapse of a single-storey pool deck trigger the collapse of the adjacent 13-storey tower?

Fundamentally, it appears the single-storey failure disturbed the columns that were supporting the east wing. The fallen slab created two-storey columns, which would have been prone to buckling, or it may have been that the slab pulled laterally on the columns causing them to fail.

Two-storey columns could be seen at the base of the west tower after the collapse, where the pool deck had fallen around the columns. Those columns stood, and the west portion of the tower did not fall. This was likely due to a combination of factors: the columns in this area were larger because they supported the surface parking; there was no beam along the west tower columns, so the connection between the slab and the columns was weaker; and the west tower housed the elevator shaft, which was surrounded by very strong shear walls. Regardless, failure of the columns at the base of the east wing triggered its progressive collapse over a period of about 10 seconds.

There have been at least four similar failures of reinforced concrete parking garages in Canada over the last 30 years. In the mid-1990s, the garage roof deck of a Mississauga condominium collapsed. In 2008, a floor of parking in a Montreal garage fell to the floor below, killing one. In 2010, a floor of parking in a Kingston, Ont., hotel collapsed to the floor below.

And again in 2010, the garage roof deck over a single-storey parking garage collapsed in Windsor, Ont. In all four cases, the nearby columns withstood the failure without collapsing, and the adjacent towers remained standing. This was, however, good luck and not good management. If any of the adjacent columns had buckled or been pulled over, this could easily have triggered a similar progressive tower failure.

The Surfside building sat right on the beach. On the oceanfront, it was always exposed to salt-spray. Salt is kryptonite to reinforced concrete structures because it induces corrosion of the embedded reinforcing steel, causing structural deterioration.

Buildings exposed to salt, whether from the ocean, from de-icing chemicals, or because it was added to the concrete during construction (a practice which was discontinued in the late 1980s but which continues to plague some older buildings) must always be protected using waterproofing materials and monitored closely so that structural deterioration can be repaired as it arises.

Governing flaws

The cause of the collapse of the single-storey garage is unlikely to be single-faceted. When learning from this failure, it is important to separate the factors over which the condo board had no control from those over which they had full control.

The investigators are likely to uncover defects in the original design and construction. Settlement of the site may also be a contributing factor, as may have been the construction of an adjacent development. None of these were under the control of the board.

However, there is also clear evidence from the site that some factors within the board’s control are likely culprits.

The pool deck was originally constructed with a tiled finish on the concrete slab, acting as the only waterproofing. When leakage originally occurred, rather than strip the tile to permit the slab to be properly waterproofed, the corporation, possibly following less-than-ideal advice, installed a membrane on top of the tile and then covered this with sand and concrete pavers.

This may have proved a temporary fix, but it added load to the pool deck slab. We can assume that a structural engineer was engaged at the time to ensure the slab could withstand the additional loads, but regardless, the extra load related to the pavers, and to the addition of some planters not shown on the original drawing would not help as the structure aged and deteriorated.

It also appears that the drains added when the pavers were installed drained at the level of the surface of the pavers, rather than being bi-level drains that drained both the surface and the level of the original tile/slab. Ponding water is evident in many photos of the site, adding further load and helping salt penetrate the structure.

When further leakage occurred, the corporation attempted repair by injection-sealing the leaking cracks from below, again, possibly following poor advice. Injection from below is never appropriate if the slab above is exposed to salt. This simply plugs the crack but provides no protection to the top surface of the slab above. The salt water continues to access the structural slab, where it can drive deterioration that is invisible—hidden below the surface finishes.

The structural deterioration was readily visible in some areas, even to a lay-person. There were chunks of missing concrete and rusted reinforcing steel, visible in both the garage and on balconies. This would have developed over years, not weeks. Yet no, or at least insufficient, action was taken until the 40-year recertification process was started. Then, a plan was initiated to address the issues, but this plan could not be implemented because there were insufficient funds in the corporation’s reserve fund.

A typical story of poor governance ensued, with one board resigning before a second board came in and was able to start the $15-million special assessment needed to fund the deferred maintenance. However, the three-year delay in moving forward allowed ongoing deterioration and prevented the repair from being completed on time.

This failure could have been prevented.

Exposing the top surface of the slab and proper waterproofing would have addressed leakage as it developed. As deterioration occurred, structural repair should have been completed periodically. Occasional condition evaluations, completed during the life of the building, could have identified hidden concerns.

Proper reserve fund studies, relying on the condition evaluation reports, would have ensured that the corporation set aside the money needed to complete the work, and in a timely manner. Good governance should have existed so that boards had the clout to implement the appropriate, but potentially painful fee increases that were needed.

Reserve fund diligence

In Canada, there are no 40-year recertification programs, nor any mandatory structural reviews except for parking garages in Quebec. After the 2012 collapse of a portion of the steel framed Algo Mall in Elliot Lake, which killed six, the Building Safety Technical Advisory Panel recommended mandatory periodic structural evaluations of medium- and high-risk buildings in Ontario. However, the Ministry of Municipal Affairs and Housing has not yet implemented these recommendations via the Building Code.

Most provinces and territories require periodic reserve fund studies. While the individuals completing these studies may have the technical know-how to spot a developing structural concern, this is not always the case.

In Ontario, a recent guideline, published by Professional Engineers Ontario, suggests that reserve fund studies for certain high-risk buildings, including all high-rise buildings, should involve a professional engineer, notwithstanding the laxer list of reserve fund study providers included in the Condominium Act.

This shift to engineers as reserve fund study providers for high-risk buildings should help reduce risk, as Ontario engineers are required to regard their duty to public welfare as paramount. This means that they can’t notice an imminent structural concern and simply report it to the client, as appears to have been the case in Surfside. They must ensure that action is taken to address the concern.

Reserve fund studies aren’t the only solution. There are many forms of structural deterioration the study’s visual review cannot evaluate, such as wood-framed buildings and steel buildings that often have coverings over the structural connections.

Post-tensioned buildings, which are relatively common in condominiums, particularly in Toronto, Alberta and British Columbia, can suffer corrosion of the embedded steel cables, even without the presence of salt, which can result in rapid progressive failure without any visible surface deterioration to provide a warning.

As such, condominium corporations should exercise due diligence and complete periodic component evaluations—balconies, cladding, parking garages, post-tensioning cables and even electrical systems—as the building ages.

A good reserve fund study will set out the necessary component evaluations to complete, as these can be paid for from the reserve fund. Subsequent reserve fund studies can reference these evaluations to ensure funds are available in time to complete the required repairs.

Diligent boards will also avoid any activity that adds excessive additional load to a structural slab, whether in the form of adding more finishes, allowing large vehicles onto a suspended slab, or even allowing trees to grow unchecked on top of a structural slab. Boards should promptly implement fee increases to adequately support the reserve fund. Delaying, deferring and ignoring seldom end in success.

Canadian condominiums have every opportunity to avoid a catastrophe like the Surfside collapse; however, this requires diligent oversight by the board, good governance, and proper funding of their reserve funds.

Sally Thompson is a managing principal at Synergy Partners and past-president of CCI Toronto.