Although there remain many legal, environmental and political issues to be resolved before any development can proceed on Grove Isle, we believe the logistical issues of developing a large new project on the far side of a small island, already with over 500+ residential condominiums, quite daunting. To obtain detailed analysis and expert consideration from a third party removed from this discussion, we queried an experienced construction engineer in order to obtain a professional opinion. The comments made regard either the developer’s Plan A (the tower) or Plan B (five story horizontal development), both of roughly equivalent size. We specifically wished to learn the options that any contractor would have for the demolition phase, the construction phase, and the completion phase.
The challenge is that this is a large project proposed on a very tight, thin and long slice of Grove Isle. This island, connected to the mainland by a two lane causeway that is rated for 15 tons, is fully occupied and the primary residence for many families. Plan A is positioned on the exact opposite side of the island from the causeway entrance. The island is surrounded by Biscayne Bay, and the bay is about 2-4 feet deep within a half mile of the island perimeter except where dredging was performed to approximately eight feet many decades ago in the marina area.
Preparation phase: During the preparation phase space for the trucks, supplies, workers’ parking will be reserved and secured. Presumably, chain linked fencing and lighting will be installed to minimize theft and vandalism of construction materials. There will be signage for resident traffic detours, placement of construction trailers, and the need to reserve a large area for outgoing debris and incoming building materials. Given that 4 Grove Isle covers about 40% of the circumference of the island, all of these activities will necessarily be in close proximity of 1, 2 and 3 Grove Isle.
Demolition phase: During the demolition phase, the existing hotel, club building, spa, roadways, parking structures and other related structures will be demolished, and the debris, asphalt, concrete, glass and metal removed. As a crude estimate, our consultant suggests that this will involve the removal off-island of about 15,000 tons of debris. Given the 15 ton limit of the causeway, approximately 1000 dump truck runs will be required if removal is by land. If removal is by sea, standard dump barges would be used. These barges, which hold about 2400 tons of debris, draw 14 feet of water. Six or seven barges would be required. However, nowhere in Biscayne Bay is the water depth 14 feet. Either a channel would need to be dredged from the ocean to approximately 16 feet deep or many more but much smaller barges that draw considerably less water could be used. Nonetheless, there is currently no channel to the island to support even medium size barges. See the image of the government chart of Biscayne Bay below. Grove Isle is shown within the large red circle. A number of the depth readings, also circled in red, are indicated in feet.
Construction phase: In this phase, the 18 story tower (Plan A) or multiple lower sized buildings (Plan B) will be constructed on the development site. This involves the building of the foundation, preparation of elevator shafts, and assembly of the steel framework. Next, concrete is poured for floors, and exterior windows and facades installed. When tight to weather, the interior walls are built, and the plumbing, electrical and HVAC installed. Finally, interior walls are tiled or painted, appliances and cabinetry installed, and floors laid with wood, carpet or stone. Modern construction techniques usually perform many of these activities in parallel, from the lower floors to the top floors, in sequence. This entails the delivery to the island and to the construction site specifically of about 30,000 tons of materials, including cement, steel, glass, mechanicals, HVAC, etc. Again, from the analysis above, this will require over 2000 trailer trucks and cement trucks or many specialty barges to accomplish importation of these materials. Furthermore, new roads and parking areas will need to be built.
Completion phase: There will be a “clean up and furnishings phase” where all the construction infrastructure will be removed and the luxury property prepared for sale. Many of these apartments will be custom designed by new owners working with their own group of decorators, contractors and subcontractors. The windows, glass walls, mechanicals, railings, paint and all the interior common furnishings are loaded at this phase. Depending on how well these new units sell, this period could be relatively short (six months) to multiple years. All new residents will need to move in and load their personal furniture and furnishings.
Duration: The duration of this development can be approximated using a construction “time line.” The estimate for a project of this scope, with its attendant logistical issues, is at best 2.5 to 3 years for preparation and building construction. This assumes NO legal or unexpected events, unforeseen environmental issues, and the absence of labor strikes. Custom design and modifications of each unit by their owner could take at least an additional year. If the developer were to obtain all permits necessary to begin construction in early 2016—one and a half years from now—the project would be completed by 2020. In the interim, much of the island would be a construction site. The effect on sales of existing condos is uncertain but there is no reason to believe that construction on this scale would enhance valuations. More likely, turnover of condos during this period would be decreased and price per square foot would diminish. After 2020, valuations become more difficult to predict.
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Note: All values and statements cited above are based on our opinions and estimates