CRE glossary
Demising wall
A demising wall is the wall separating one tenant's premises from another tenant's premises or from a common-area corridor. It defines the legal boundary of the leased space. Demising walls must meet specific construction standards (fire rating, sound rating, slab-to-deck) to satisfy code and provide privacy between tenants.
Demising walls are typically 1-hour fire-rated and built slab-to-deck (full-height, not just to drop ceiling) to meet most building codes. They include sound-attenuation insulation to prevent voice carry between tenants, a real concern for law firms, therapy practices, and other privacy-sensitive uses. Substandard demising walls (drywall to drop-ceiling only) are common in older Class B/C buildings and create real operational issues.
When a tenant takes a partial floor, the demising-wall location is negotiated at LOI. The tenant typically wants more space at the same rent; the landlord wants to maximize leasable area. Demising-wall placement also affects the tenant's HVAC zone, electrical service, and life-safety access, all of which can be downstream costs.
Demising-wall construction is usually a landlord obligation (part of the build-out delivery) and the cost is included in TI or absorbed by the landlord directly. Confirm at LOI: who pays for the demising wall, what the wall specifications are, and when the wall must be complete (typically before the fixturing period begins).
Example
- Standard office demising wall
- 1-hour fire rated, slab-to-deck, R-19 sound batt
- Sub-standard demising wall
- Drywall to drop ceiling only
- Premium demising wall
- STC-50+ acoustic rating for noise-sensitive uses
- Cost (typical)
- $50–$120/linear foot
Broker perspective
Tenants assume demising walls are 'just there', they're not. In a multi-tenant suite or partial floor, getting full slab-to-deck construction with proper sound attenuation is non-trivial. Sub-standard demising walls cost the tenant in operational privacy for the full lease term. Specify 1-hour fire-rated, slab-to-deck, with R-19 sound batt or better at LOI.
Frequently asked
People also ask
Who pays for the demising wall?
Usually the landlord, as part of the space delivery / build-out. Confirm in the LOI.
Does the demising wall affect the rent?
Yes indirectly, its placement defines the leased SF. Rent is calculated on the SF inside the demising wall.
What's a 'common-area' vs 'demising' wall?
Common-area wall separates tenant space from corridors/lobbies. Demising wall separates tenant from tenant. Both are 'demising' walls in casual usage.
Can I move a demising wall mid-term?
Only with landlord consent and at the tenant's cost. Demising-wall changes affect leased SF, so they typically require lease amendment.
Related terms
Build-out (fit-out)
The construction work to customize a leased space for the tenant, paid via TI allowance, tenant cash, or both.
Tenant improvements (TI / TIA)
Money the landlord contributes toward customizing the space for the tenant, usually expressed as $/SF.
Letter of intent (LOI)
A non-binding outline of the major business terms, rent, term, TI, options, that becomes the basis for the binding lease.
Rentable vs usable square feet (RSF / USF)
USF is the floor area you can actually use; RSF adds your share of common areas. The ratio between them is the load factor.
See demising wall extracted from a real lease.
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