Leasehold improvements, the work that turns a leased unit into a custom office, shop or plant, need more than a contractor and a start date. The lease, the size and use of the building, the fire protection systems and each trade bring their own approvals, and most take time. This guide walks through them in the order you will meet them in Toronto, from landlord consent to the final inspection, with tips for working in a building that stays open.
1. Start with the lease and the landlord
The lease sets the first rules. Read its alterations clause before any design work, and get the landlord’s written approval of the drawings before you apply for permits. Questions to settle early:
- Which work needs consent, and how long the landlord takes to review drawings.
- Who may work on base-building systems such as the sprinklers, fire alarm, HVAC and electrical service.
- Insurance, permitted work hours, elevator and loading dock bookings, and noise rules.
- Who pays for which improvements, and what must be removed or restored when the lease ends.
If the lease is still being negotiated, these points are easier to settle before it is signed.
2. Work out which rules apply to your building
Ontario’s Building Code sorts buildings into two groups, and the test is the whole building, not your unit. Part 9 covers buildings of up to three storeys with a building area (footprint) of 600 m² or less, used for offices and personal services, retail, or medium- and low-hazard industry. Part 3 covers larger buildings, and any building with an assembly, care or detention use or high-hazard industry, whatever its size. A small suite in an office tower is a Part 3 project.
Size and use also decide who prepares the drawings. Under the Architects Act, alterations in an office, personal services or retail building over 600 m² in gross area (all floors above grade) or over three storeys, and in any assembly or institutional building, need an architect, with a professional engineer for the engineering. In an industrial building past those limits, an architect or an engineer may prepare the design.
Within the limits, the Act does not require an architect, and the drawings can come from a designer registered under the Building Code, who must show their registration number on them. The two tests measure differently: the code split uses footprint, the Architects Act uses total floor area above grade, so a two-storey office building can be Part 9 and still need an architect. Interior design alone (finishes, furniture and partitions) is exempt from the architect requirement only if it does not affect the structure, a fire safety system or fire separation, a main entrance, a public corridor, an exit or an exterior wall, and does not add floor space such as a mezzanine.
Where an architect or engineer is required, they also carry out general review during construction, and Toronto asks for a signed commitment to general reviews with the application.
3. Get the building permit
Under the Building Code Act, a material alteration needs a building permit. In Toronto that includes adding or removing walls and installing or modifying heating or plumbing, while cabinetry and millwork alone do not. The City’s application for interior alterations to a non-residential building asks for:
- A site plan and key plan showing where the work is.
- Floor plans showing existing and proposed uses of every space and all plumbing fixtures, a reflected ceiling plan, wall assemblies and fire separations.
- Sections, construction details, guard details, and door and finish schedules.
- Information on the building’s existing life safety systems, on the City’s form or an OBC matrix.
Fees are charged on the area receiving work. In 2026 the rate is $12.45 per m² for assembly, institutional and office space and $11.53 per m² for retail and industrial space, with a $214.79 minimum.
Check two more triggers. A change of use, such as office to retail, retail to office, or either to a restaurant with more than 30 seats, is a change of major occupancy that needs a permit even if nothing is built, although the fit-out’s building permit can cover it.
Accessibility can be triggered too. Under Part 11 of the code, new interior walls or floors in a suite larger than 300 m² must generally meet the barrier-free requirements of Section 3.8 when the suite is on a floor within 200 mm of the outside ground level, or reachable by passenger elevator from such an entrance. Other suites with new walls must still meet a shorter list of barrier-free provisions.
4. Sprinklers, fire alarm and Toronto Fire
When walls and ceilings change, fire protection such as sprinkler heads and fire alarm devices may have to move or be added. In Toronto, relocating heads or alarm components as part of an interior alteration adds no extra permit fee, while replacing or extensively modifying them is charged at the applicable rate. In a Part 3 building, the City refers the life safety rough-in inspection to Toronto Fire Prevention, and the final interior inspection waits until the life safety systems and every fire separation are complete.
During construction, Ontario’s Fire Code applies. The Chief Fire Official must be notified when alterations will interrupt a sprinkler system, and the fire department, occupants and the building’s supervisory staff must be told whenever a sprinkler or fire alarm system is shut down. The contractor has to plan sprinkler work so the system is back in service as quickly as possible, so agree the shutdown schedule with the property manager in advance.
5. Mechanical, plumbing and electrical permits
HVAC and plumbing changes need permits as well. In a Part 3 building they are inspected at rough-in: HVAC before insulation, fire dampers and equipment go in, and plumbing when the piping is ready for testing. In Toronto, a plumbing business must hold a City Plumbing Contractor licence.
Electrical work runs on a separate track. The Electrical Safety Authority (ESA) is clear that a building permit is not an electrical permit and you may need both: most electrical work must be reported to ESA with a notification of work before it starts, and an inspection must be requested before wiring is concealed. Almost all electrical work must be done by a Licensed Electrical Contractor, and general contractors and electricians may not do it unless they are an LEC themselves or employed by one. When the review is complete, ESA issues a Certificate of Acceptance, which it describes as important for resale and insurance.
6. Review times, inspections and moving in
Toronto reviews complete applications within 15 business days for Part 9 buildings other than houses, 20 for large Part 3 buildings and 30 for complex ones. An application only counts as complete once a Zoning Applicable Law Certificate has been issued, so apply for that first. Office and retail alterations up to 600 m², and assembly or industrial alterations up to 300 m², with no change of use or patron area can go through Express Services, which aims to review them within 3 business days.
Signs are separate: a sign fixed to a building or set into the ground needs both a sign permit and a building permit, and the standard turnaround is 10 business days.
Once work starts, call for each inspection as you reach it. Toronto inspects within two business days of the date you request, and anything covered before it passes has to be opened up. For a Part 3 fit-out the stages include fire separations before finishes and ceiling tiles, HVAC and plumbing rough-ins, the life safety rough-in and a final interior inspection, and a final inspection closes the permit. To occupy part of the space before everything is finished, you need a permit to occupy first, and the code requires, among other things, that exits, fire separations, sprinklers and the fire alarm serving that area are complete and working.
7. Scheduling work in an occupied building
If the building stays open during the fit-out, a few rules shape the schedule:
- Noise. Toronto’s noise by-law prohibits clearly audible construction noise from 7 p.m. to 7 a.m. on weekdays, before 9 a.m. and after 7 p.m. on Saturdays, and all day on Sundays and statutory holidays, unless you hold a noise exemption permit. Plan loud work such as demolition and coring for permitted hours, or apply for an exemption.
- Phasing. Toronto notes that phased projects may need additional inspections, so agree the phases with your inspector at the start.
- Shutdowns. Group sprinkler and fire alarm work into short, planned windows, since every shutdown needs notice.
- Occupied areas. Keep the exits and fire separations serving any area still in use intact while the work moves around it.
How MKC can help
MKC Group’s commercial and engineering teams work under one roof, and we act as general contractor and project manager, so one team takes a fit-out from the first drawing to the final walkthrough. Our engineering department prepares the drawings and engineering letters and applies for the permits, and we use ECRA/ESA-licensed electrical contractors for the electrical work. Call (647) 637-6052 or request a free estimate.