A tenant improvement HVAC scope should state which work is tenant-side and which belongs to the base building, what the landlord must approve before work starts, and when work is allowed. It should list duct, diffuser, VAV box, zoning and thermostat changes by location, name who handles electrical, ceilings and permits, and define after-hours access, so the bid matches what the building will actually permit.
- A TI scope starts with a boundary: what is the tenant's mechanical system, and what is the landlord's base-building system you are only connecting to.
- Landlord approval is a scope item. Plans, equipment changes and work on shared systems usually need written sign-off before ordering anything.
- VAV box adds and relocations are only as good as the air available upstream. The scope should say who confirms supply capacity.
- Thermostat and zone changes need a defined point of control, otherwise a new zone gets built that nobody can adjust.
- After-hours work is normal in occupied buildings. The scope should name hours, access, freight and noise rules rather than leave them for later.
Draw the line between tenant work and base building
Almost every TI dispute traces back to one question: whose system is it? In a leased suite, the landlord typically owns the central plant, main risers, rooftop equipment serving the floor and the primary supply duct. The tenant's work usually starts at a connection point downstream of that, but leases differ, so the scope should not guess.
Put the boundary in writing, floor by floor if needed. A one-line statement such as "work begins at the base-building branch connection shown on sheet M-2" removes a large category of argument later. If the lease or work letter defines the split, reference it by name in the scope.
| Item | Usually tenant scope | Usually base-building scope |
|---|---|---|
| Branch ductwork and diffusers inside the suite | Yes | No |
| Main supply and return trunks, risers | Connect to only | Yes |
| VAV boxes serving the suite | Often yes when added or moved | Sometimes owned by landlord even inside the suite |
| Rooftop or central equipment | Only if the TI adds a dedicated unit | Yes |
| Controls tied to the building system | Suite-level devices | Head-end, graphics, network |
| Fire dampers, smoke detection interface | Coordinate | Often landlord-controlled |
What the mechanical scope should list
A good TI scope reads like a marked-up floor plan in words. Each item has a location, an action and a result. Vague lines such as "modify ductwork as needed" are where change orders come from. See how to write a commercial HVAC scope of work for the general structure.
- Demolition of existing branch duct, diffusers and controls in the affected area, with a note on what is reused versus discarded.
- New or relocated branch duct, flex runs, diffusers and returns, by room or zone.
- VAV boxes added, relocated or reheated, with the reheat type stated.
- New thermostats or sensors, with mounting height and location coordinated to the architectural plan.
- Connection to the base-building control system, if one exists, and who programs it.
- Air balancing of the altered zones and who performs it.
- Permit, inspection and closeout items that belong to the mechanical trade.
Duct and diffuser changes
Ceiling grid and layout
Diffusers sit in a ceiling the ceiling contractor and lighting contractor are also working in. The scope should say who sets the grid openings and who supplies the ceiling tile cut. Mechanical typically supplies and connects the diffuser, but a flat statement removes doubt.
Reuse of existing duct
Reusing old duct saves material but carries risk. Existing flex may be sagging, torn or insulated with deteriorated wrap. If reuse is assumed, the scope should say whether the contractor inspects it, cleans it or accepts it as found. Add a line on how hidden conditions above the ceiling are handled, since they are a classic trigger for HVAC change orders.
Return air path
New walls that reach the deck can strangle a return. If the plan adds a full-height partition, the scope should require a transfer duct, a return grille or a plenum path, and name it.
VAV boxes, zoning and thermostat changes
Adding a VAV box is rarely just hanging a box. It adds airflow demand to a trunk that was sized for the old layout. The scope should state whether the contractor is responsible for verifying available supply air, or whether the design engineer provides the airflow schedule and the contractor installs to it.
- Confirm the airflow schedule for each new or relocated box, and who issued it.
- State the box type, inlet size, reheat and control sequence expected.
- Identify the controller and who supplies and programs it.
- Define upstream work: duct resizing, balancing dampers, static pressure reset.
- Define the thermostat or sensor served by each box and where it mounts.
Zoning changes deserve their own line. Combining three offices on one thermostat is a design decision, and splitting a conference room onto its own zone is another. The scope should record which zones exist after the work, so occupants have a way to ask for adjustments. Controls tied to the base building are covered in more depth in building automation controls upgrade scope of work.
Landlord approval and coordination sequence
Treat approval as a sequence the schedule depends on. Order equipment only after the steps that gate it are done.
- Submit mechanical drawings and equipment data to the landlord or property manager for review.
- Receive written approval, including any conditions on riser access, roof access or shutdown windows.
- Confirm insurance certificates and any contractor registration the building requires.
- Schedule shutdowns or tie-ins to base-building systems with building engineering.
- Confirm permit status with the authority having jurisdiction before starting concealed work.
- After completion, deliver as-built markups and balance reports to the landlord if the lease requires them.
A TI mechanical scope touches electrical service to new boxes, ceiling patching, fire-life-safety interfaces and structural support. Davinci's mechanical, refrigeration and controls work is performed by its own UA Local 250 crew. The scope should name who performs electrical, ceiling and any structural work, and the owner or general contractor should confirm the responsible licensed party for each.
After-hours work and occupied-building constraints
Office towers and medical suites often restrict noisy work, shutdowns and freight use to nights or weekends. If the work is after hours, say so in the scope and define what that means in your building: allowed hours, freight elevator reservation, loading dock access, security escort and whether the building charges for after-hours HVAC.
- Hours of permitted work and any blackout days such as month-end or tenant events.
- Dust, noise and odor controls near neighboring tenants.
- Protection of finished corridors, lobbies and elevators.
- Temporary cooling or heating if a zone is down during occupied hours.
- Refrigerant, solvent or brazing restrictions if the building prohibits hot work near occupants.
Phasing in occupied space is a larger topic; the same logic is covered in phasing an HVAC conversion in an occupied office.
Contractor shall furnish and install branch duct, diffusers, returns and VAV boxes in the areas shown on the mechanical drawings, beginning at the base-building connection points identified by Owner. Work requiring shutdown of base-building systems or use of freight elevators shall be performed during the hours approved in writing by building management. Contractor shall not order equipment until Owner confirms landlord approval of submittals. Electrical service, ceiling work and fire-life-safety modifications are excluded unless listed.