How a condominium tower can look like 400 development sites
Finding underused properties requires reliable data on what is already built and what the zoning allows. Condominium records are one of many challenges in preparing that data. For example, an individual unit can be mistaken for a separate development site.
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One tower can arrive as hundreds of property records
A county may give every apartment in a condominium its own property record. For example, a tower with 400 apartments can arrive as 400 records and 400 stacked geometries. A search that treats each geometry as a separate parcel could return 400 development sites.
Some counties repeat the same land outline for every unit. Others draw each unit as a smaller shape within the property's boundary.
Two common ways counties represent condominium units: repeated outlines on the same land, or smaller unit outlines within the property.
One apartment can make the whole property look almost empty
In one case, every apartment had a map outline covering the same 89-acre lot, with the outlines stacked on top of one another. If the search used just one apartment's record, it would mistake that apartment's 1,500 sq ft for the total floor area of the entire 89-acre property.
The property's total existing floor area was 938,424 sq ft. A search using only 1,500 sq ft would leave almost all of the property's existing floor area out of the comparison. The property could look almost empty.
The search needs the condominium property as a whole, with the existing floor area of all its units, to compare with what zoning allows. That means linking the units to the property they belong to.
In Delray Beach, 254 condominium properties were missing
Palm Beach County links condominium units through a shared parent parcel number. In Delray Beach, those numbers group 15,375 units into 254 condominium properties. Many of those properties contain several buildings, so 254 is a property count, not a building count.
Parcel-finder prepares the property and zoning data behind our development searches. It should list each condominium property once. In Delray Beach, we had removed the 15,375 individual unit records from that list, but had not created entries for the properties they belonged to. Without those property entries, a development search would miss all 254 condominium properties.
Our automated condominium check scored 100%, even though it failed to detect that all 254 properties were missing.
We fixed the infrastructure to include these properties and prevent the same omission from recurring. We then found another error: all 254 were mislabelled as not being condominiums. We corrected the infrastructure so these properties are recognised as condominiums each time the city's data is prepared.
One of the runs Delray Beach went through: 254 condominium properties had been added, but every site was still marked as not a condominium.
Ann Arbor's unit records have no shared parent number
The Washtenaw County unit records do not have the shared parent parcel number used in Palm Beach County. We use repeated map outlines, regional building identifiers and the city's building footprints to establish which units belong together.
At Tower Plaza, nearly 300 units appear across 67 map shapes. A building identifier from the Southeast Michigan Council of Governments links the unit records. The city's building outline also connects the ground-floor shops on Maynard Street to the tower. We checked those connections against street view.
A unit with its own house and lot stays a separate property, even if the county records it as a condominium.
We also do not label a condominium unit vacant merely because no building appears on the map. In one case, street view showed a house that the map had missed. This is not a straightforward process, and we are just talking condominiums.
The whole condominium property has to remain searchable
We now require a condominium property to appear once, identified as a condominium. Units inside a shared building must not appear as separate development sites. If we cannot interpret a county's records, preparing the city's data stops rather than leaving the property out.
In Delray Beach, 31 of the 254 properties still have no total floor area because the county supplies no areas for their individual units. We publish those totals as unknown, rather than zero. Until those areas are available, we cannot compare the properties' total existing floor area with what zoning allows.
It would be easier to remove every condominium from the search, but that would hide real development opportunities. A condominium's buildings may use much less than today's zoning allows. A developer could pursue such a property by buying its units individually.
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