(CNN) An engineering firm hired for Champlain Towers South's milestone recertification found "deep" concrete deterioration near the pool but couldn't perform repairs, in part, because of concerns about stability, according to an October letter.
Maryland-based Morabito Consultants also was hamstrung because it needed access to the inside of the pool, which "was to remain in service for the duration of this work," the firm said in its letter.
Because the pool couldn't be closed and Morabito had stability concerns, tower management was advised that work in the pool area "would be limited to removal of only loose concrete," the letter said.
Morabito also directed Concrete Protection & Restoration Inc. to perform "exploratory demolition" in five areas on the building's first floor, and CPR found "some curious results as it pertained to the structural slab's depth," the letter said, without elaborating.
The nine-page letter summarizing the work, which was addressed to condominium association board president Jean Wodnicki and property manager Scott Stewart, is yet another indication of problems with the building's concrete. The concrete in the pool and underground garage area is increasingly becoming a focus as engineers and government officials work to learn what caused the June 24 partial collapse in Surfside, Florida, that killed at least 20 people and left another 128 unaccounted for.
Still, there's no indication thus far that concrete deterioration played a role in the collapse, but several engineers have told CNN that it's one of multiple factors to consider in investigating the disaster.
Morabito inspected Champlain Towers South in 2018 as part of the building's 40-year recertification -- a stringent process for upgrades and improvements enacted after Hurricane Andrew in 1992. The firm found that failed waterproofing beneath the pool deck caused "major structural damage to the concrete structural slab" and warned of rapid deterioration if it wasn't promptly replaced, according to its report.
In April, Wodnicki warned residents that "the concrete deterioration is accelerating," with some areas having gotten worse since the 2018 inspection. Wodnicki's letter outlined millions in repairs that the condo association later approved.
The 2018 report did not indicate the structure was at risk of collapsing, nor did Wodnicki's letter to residents.
In the October letter, Morabito said repair work could not be done because it would "affect the stability of the remaining adjacent concrete constructions." The firm did not specify which constructions might be destabilized, and it's unclear if the engineers meant nearby buildings or other structures within Champlain Towers South. But the firm noted concrete deterioration deep within the pool's wall and corbel, a type of support structure, requiring "aggressive excavation of concrete."
Morabito and CPR removed loose concrete from the perimeter of the pool pump room, which was showing signs of cracking and which presented "a fall hazard," the October letter said.
As for the unspecified "curious results" of the excavation work, Morabito requested "that additional core work be performed by CPR to confirm/clear-up said results," Morabito said in the letter.
Among other work done, according to the letter: CPR replaced the bottom of a deteriorating stair column base with hollow steel structural sections; conducted exploratory demolition on the underside of an eave that required "removal and reconstruction"; and removed all loose "cracked, spalled, deteriorated, and delaminated concrete" and damaged stucco from the underside of balcony eaves on 114 of the building's 136 units, the letter said.
According to the letter, CPR also performed exploratory demolition on five 3-square-foot sections of the building and planned to demolish paver systems at the pool deck, concrete in the parking area and drive aisle, and the planters down to the existing waterproofing layer -- all of which were cited in the 2018 report and the April letter to condo owners.
Photos accompanying the report included the rusty stairwell column that was replaced, the pool corbel's "loose, cracked, spalled deteriorated concrete" and exposed rebar, water damage to balcony eaves, and other damage to eaves and stucco on the building.
Morabito Consultants did not respond to CNN's request for comment on the letter, but it has defended its work at the tower in previous statements.
CPR in a statement Friday said the company did not repair or restore concrete in 2020 on Champlain Towers South.
It said: "Our company was contacted by the Champlain Towers South Condominium Association in 2020 to assist Morabito Consultants in their investigations relative to the building's 40-year recertification project. Concrete Protection & Restoration, LLC did not undertake any actual concrete repair or restoration work on the Champlain Towers South building in 2020.
"Our services on this project were directed by Morabito Consultants so they could evaluate the building for its 40-year recertification. We removed loose, cracked, spalled, deteriorated and delaminated concrete from the balcony soffits of 114 units as well as pool corbels to prevent it from falling, and removed all deteriorated, debonded and falling stucco from balconies. We also did exploratory services that involved removing pavers on the patio deck to allow the engineers to see conditions underneath and removing the false ceiling in the front parking area to enable the engineers to see the underside of the slab. Additional exploratory services included taking core samples from locations identified by Morabito Consultants so their engineers could analyze the existing condition of the concrete."
Attempts to reach Wodnicki and Stewart, the property manager, were unsuccessful.
The condo association, which has been named in lawsuits accusing it of failing to maintain the building, released a Friday statement saying, "Answers will take time as part of a comprehensive investigation and we will continue to work with city, state, local, and federal officials in their rescue efforts, and to understand the causes of this tragedy."
The full scope of the concrete work needed at Champlain Towers South remains unclear, as does the specific work contracted to Morabito Consultants and CPR. Whether the work had been scheduled or was under way is also unknown.