Multi-Tenant Floor Measurement
BOMA measurement rules for floors with multiple tenants, including floor common area identification, allocation methods, and the relationship between usable and rentable area.
Methodology
On a multi-tenant floor, areas outside any tenant's demised premises but within the floor's boundaries (excluding vertical penetrations) are classified as floor common areas. These include corridors, shared restrooms, electrical/telecom closets, and shared pantries. Floor common areas are allocated to each tenant using Method A or Method B, increasing their usable area to arrive at floor usable area. The building common area load factor is then applied to arrive at rentable area.
BOMA 2017 vs 2024
BOMA 2024 strengthens the guidance on floor common area identification, particularly for floors where one tenant occupies the majority of the space. The 2024 standard clarifies that even when one tenant has 80%+ of a floor, if there is more than one tenant, multi-tenant floor measurement rules apply (unless the minority tenant's space is classified differently).
Worked Example
A 20,000 SF floor (after deducting 1,500 SF vertical penetrations = 18,500 SF floor area) has three tenants: A (8,000 SF usable), B (5,000 SF usable), C (3,000 SF usable), plus 2,500 SF floor common area. Under Method B: A's allocation = 8,000/16,000 × 2,500 = 1,250 SF. A's floor rentable = (8,000 + 1,250) × building load factor 1.12 = 10,360 SF.
Financial Impact
Floor common area allocation typically adds 10-18% to a tenant's usable area on a multi-tenant floor. Choosing Method A vs Method B can shift 2-5% of rentable area between tenants on the same floor, creating winners and losers among co-tenants.
Lease Implications
Multi-tenant floor leases must specify the BOMA method (A or B) used for floor common area allocation. The lease should also address what happens when the floor configuration changes — if a tenant expands or a new tenant is added, will the remaining tenants' areas be remeasured?
Common Errors
- Omitting floor common areas from the allocation (understating tenant rentable areas)
- Using inconsistent methods (A vs B) across different floors
- Failing to reclassify floor common areas when a tenant expands or vacates
- Including vertical penetrations in the floor common area pool
Additional Context
Multi-tenant floor measurement is where most BOMA disputes originate. The interaction between floor common area allocation (Method A/B) and building common area allocation (load factor) creates a two-tier system that many property managers and tenants find confusing.
Related Resources
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