Lobby Area Measurement and Allocation
How building lobby areas are classified and allocated under BOMA standards, including ground-floor lobbies, elevator lobbies on upper floors, and the distinction between building common area and tenant-accessible amenity space.
Methodology
Ground-floor lobbies are classified as building common area. They serve all occupants and visitors regardless of floor. The entire lobby area (reception, security desk, elevator waiting area, circulation paths) is included in the building common area pool and allocated to all tenants through the building load factor. Upper-floor elevator lobbies on multi-tenant floors are classified as floor common area and allocated only to tenants on that floor. On single-tenant floors, the elevator lobby becomes part of the tenant's usable area.
BOMA 2017 vs 2024
BOMA 2024 provides more nuanced lobby classification. The 2017 standard treated all lobby areas as building common area. The 2024 update distinguishes between functional lobbies (reception, elevator waiting, security checkpoint) which remain building common area, and amenity lobbies (lounge seating, coffee bar, collaborative space) which may be classified differently if they serve a dual function.
Worked Example
A building has a 5,000 SF ground-floor lobby and 200 SF elevator lobbies on each of 20 upper floors (10 multi-tenant, 10 single-tenant). Building common area includes the 5,000 SF lobby. The 10 multi-tenant floors each have 200 SF of floor common area (elevator lobbies). The 10 single-tenant floors include their 200 SF elevator lobbies in tenant usable area. Total lobby-related area: 5,000 SF building common + 2,000 SF floor common + 2,000 SF in tenant usable = 9,000 SF total.
Financial Impact
Lobby size directly affects the building load factor. A 5,000 SF lobby in a 200,000 SF building contributes 2.5% to the load factor. Renovating a lobby from 3,000 SF to 6,000 SF (adding a lounge, fitness preview, etc.) increases the load factor by 1.5%, costing every tenant approximately $0.75/SF at $50/SF base rent.
Lease Implications
Leases should address lobby renovation scenarios. Many landlords include provisions allowing lobby expansion with corresponding load factor increases. Tenants should negotiate caps on building common area increases to protect against lobby expansions that increase their costs without benefiting their operations.
Common Errors
- Classifying upper-floor elevator lobbies as building common area instead of floor common area
- Including lobby retail space (cafש, newsstand) in building common area when it is separately leased
- Failing to reclassify elevator lobbies when a floor converts from multi-tenant to single-tenant
- Double-counting lobby circulation areas that also serve as building corridors
2026 Review Controls for BOMA-Driven CAM Math
BOMA measurement changes affect CAM only when the lease, rent roll, or reconciliation denominator accepts the measured area. Confirm the measurement source before changing tenant shares.
- Record the BOMA standard version used for the rent roll and lease abstract.
- Compare tenant RSF, building RSF, and load factor against the reconciliation denominator.
- Flag non-allocated tenant areas separately so they are not loaded twice.
- Keep the measurement certificate or architect worksheet with the CAM support file.
- Document whether the lease allows remeasurement to change existing tenant shares.
Additional Context
Lobby allocation has become increasingly controversial as landlords invest heavily in 'amenitized' lobbies to compete for tenants. Converting functional lobby space into hospitality-style amenity areas increases building common area and the load factor, effectively passing renovation costs to all tenants through higher rentable areas.
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