Unit Demising Permit Design
Permit drawings for dividing one commercial unit into multiple tenant spaces or combining adjacent units, with coordination of demising walls, exits, fire/life-safety and affected base-building systems.
What a unit-demising permit package can include
Depending on the building and project:
- existing and proposed unit plans
- new demising-wall locations and construction details
- exit access and tenant entrance information
- fire/life-safety coordination relevant to the new unit boundaries
- HVAC/mechanical, plumbing and other base-building coordination within applicable scope
- permit submission support and landlord/municipal coordination where included
What we review before drawing the demising wall
The new property/lease line on paper must work as a real code-compliant tenant boundary.
- existing unit boundaries and base-building drawings
- exit access for each resulting tenant unit
- fire separation and continuity at ceiling/roof/floor interfaces
- washroom and accessibility implications for each unit
- HVAC/mechanical zoning, electrical/service and plumbing impacts
- whether future tenant uses are known or the permit is only creating shell units
Shell demising versus tenant fit-out
A landlord may divide space before the future tenants are known, or the demising work may be submitted together with a specific tenant renovation. The permit scope should make that distinction clear so future tenant-use requirements are not accidentally represented as already approved.
Common unit-demising questions
Do I need a permit just to divide one commercial unit into two?
Yes where new demising construction and related regulated changes are being created.
Can both new units share the same exit?
That depends on the building/layout and applicable exit requirements. Each resulting unit’s exit path has to be reviewed.
Does the demising wall need a fire rating?
The required wall construction depends on the building, occupancy, separations and life-safety design. We do not assign a generic rating without project review.
What happens to HVAC when a unit is divided?
The existing system may need to be separated, balanced or redesigned so each resulting tenant space is properly served.
Can I combine two units by simply cutting an opening in the demising wall?
The opening can affect fire separation, structure, exits and services and should be reviewed before construction.
Does demising approval mean any future tenant can occupy the new units?
No. Future tenant use and fit-out still need their own zoning/permit review as applicable.
Document the final unit boundaries
Landlord and future tenant drawings should use the same approved unit configuration. Field changes to demising walls, doors or service distribution should be reviewed before being treated as the new base building.
What to send for a quote
- property address and affected unit numbers
- existing base-building or lease plans
- proposed number and approximate areas of resulting units
- future tenant uses if known
- photos of existing demising walls, ceilings and service areas
- landlord criteria and any municipal comments
Related commercial / industrial permit services
Commercial Renovation & Tenant Improvement · Office Permit · Retail Permit · Change of Use Permit & Occupancy Review
828 Design Inc. — BCIN building design & permit services. Content reviewed for current Ontario permit context: August 2026. Zoning, licensing, occupancy and permit requirements are confirmed for the actual property, municipality and written project scope. Qualifications & responsibility →
Dividing or combining commercial tenant units?
Send the base-building plan and proposed unit boundaries. We can identify the demising, exit and building-service coordination needed for permit.