Mould Remediation and Removal in Toronto: A Commercial Property Guide

Updated July 30, 2026. Prepared by Impact Restore, commercial and industrial restoration, 21 Goodrich Rd Unit 10, Etobicoke, ON M8Z 6A3. Emergency line 647-951-0906.

Direct Answer

Mould remediation in Toronto is the standards-based removal of mould contamination and correction of the moisture source that caused it. Ontario has no mould-specific regulation, so commercial obligations flow from the Occupational Health and Safety Act, and the work is classified by contaminated area into three remediation levels.

TL;DR

• Ontario has no mould-specific statute or regulation. Employer duties come from the Occupational Health and Safety Act, primarily section 25(2)(h), which requires every precaution reasonable in the circumstances [1][2].
• Ontario’s own guidance states that sustained or extensive visible mould growth on interior building surfaces is unacceptable and needs remediation [1].
• Work is classified by contaminated area into Level 1, Level 2, and Level 3 under the Environmental Abatement Council of Ontario guidelines, the framework the City of Toronto adopted for its own buildings [3][4].
• Air testing is not a prerequisite. The City of Toronto’s own policy states that sampling is not required to begin remediation or to determine the remediation level [3], and Health Canada does not recommend mould testing in offices, schools, or other non-industrial buildings [5].
• Mould can begin growing on wet building materials within 24 to 48 hours, so the drying response window matters more than the testing schedule [3].
• Clearance testing is meaningful when an independent third party performs it. Under the 2024 edition of the ANSI/IICRC S520 standard, verification counts as verification only when an independent indoor environmental professional carries it out [6].

One liner: In a Toronto commercial building, what protects you is not a mould law, because there isn’t one, but a documented process built on the OHSA duty of care, correct level classification, and independent clearance.

Key Numbers

Figure	What it means	Source
1 m2 (10 sq ft)	Upper bound of a Level 1 small isolated area of contaminated building material	City of Toronto policy, based on EACO Edition 3 [3][4]
1 to 10 m2 (10 to 100 sq ft)	Level 2 medium area	City of Toronto policy [3]
Over 10 m2 (over 100 sq ft)	Level 3 large area	City of Toronto policy [3]
1 m2 in HVAC	Threshold that pushes ventilation-system contamination to Level 3	City of Toronto policy [3]
4 m2	Toronto referral line where mould complaints move from Municipal Licensing and Standards to Toronto Public Health	City of Toronto 311 guidance [7]
24 to 48 hours	Response window for drying wet materials before mould growth takes hold	City of Toronto policy [3]
Below 60%	Relative humidity target that inhibits mould growth indoors	City of Toronto policy [3]
No numeric limit	Health Canada has no health-based exposure limit for indoor mould	Health Canada [5][8]
2024	Current edition of ANSI/IICRC S520, superseding the 2015 third edition	IICRC [6]
2 hours or less	Impact Restore’s on-site response commitment across the GTA	Impact Restore [9]

Why Toronto Commercial Buildings Get Mould

In short: Mould in a Toronto commercial building is almost always a symptom of a water problem, not a cleaning problem, and the building’s age and envelope determine where it shows up first.

Every mould problem starts with water. Ontario’s workplace guidance is blunt about this: all moulds need water to grow, and growth happens wherever there is water damage, high humidity, or dampness [1]. Buildings carrying a history of leaks, floods, fires, or poor humidity control sit at higher risk than buildings that do not [1].

Toronto’s commercial stock gives mould several reliable openings. Flat roof assemblies on warehouses and distribution centres hold standing water when drains block. Below-grade office and retail levels sit against foundation walls that sweat through humid summers. Older brick-and-block buildings across the downtown core and the inner suburbs were built before continuous air barriers were standard, so warm interior air meets cold exterior assemblies and condenses inside the wall.

The materials matter as much as the water. Water-damaged drywall, wood, jute, wallpaper, and cardboard are all prone to fungal growth [1]. That list describes the interior of a typical office fit-out and the contents of a typical storage room.

The moisture sources that produce the most commercial calls

• Roof leaks and blocked roof drains on flat commercial roofs
• Slow supply-line or drain leaks inside washroom and kitchenette walls
• Condensation on uninsulated cold-water lines and ductwork above ceiling tiles
• Foundation seepage and hydrostatic pressure in below-grade levels
• Sprinkler discharges and fire-suppression system failures
• Humidification and dehumidification faults in the building’s air handling systems
• Sewer backups, which introduce contaminated water and change the remediation approach entirely

What Ontario Law Actually Requires

In short: Ontario has no mould regulation. Commercial obligations rest on the Occupational Health and Safety Act’s general duty and on sector regulations, which is why a documented process matters more than a compliance certificate.

This is the single most misreported point in this market. There is no Ontario regulation devoted to mould. Ontario Regulation 278/05 is frequently cited as if it governed mould work, but it governs asbestos on construction projects and in buildings and repair operations [10]. Applying its Type 1, Type 2, and Type 3 language to mould is a category error.

What does apply is the Occupational Health and Safety Act. Section 25(2)(h) requires employers to take every precaution reasonable in the circumstances for the protection of workers [1][2]. The Act places duties on constructors under section 23, employers under section 25, and supervisors under section 27, and Ontario’s guidance confirms those duties extend to protecting workers from mould in workplace buildings [1]. Sections of the Industrial, Construction, Mining, and Health Care regulations may also apply to the maintenance and remediation activity itself [1].

Ontario’s guidance also sets a plain standard for when action is needed. Sustained or extensive growth of visible mould on interior building surfaces is unacceptable, and that growth is treated as a risk factor for health problems [1].

Duties that surprise property managers

Two obligations catch commercial operators off guard. First, occupants of a contaminated building should be told the mould is present and given information on its health effects [1]. Silence while a contractor works behind poly sheeting is not a defensible posture. Second, before remediation begins, someone has to consider whether other hazards sit in the same work area. The designated substances or hazardous materials inventory needs review, because asbestos or lead in the same wall cavity changes the entire scope [3]. Cutting into a 1970s office partition to chase mould without an asbestos check creates a far larger problem than the one being solved.

The Toronto property standards angle

Alongside worker protection, Toronto’s property standards regime touches mould. City guidance directs mould complaints under 4 square metres to Municipal Licensing and Standards, addressed as marks and stains under Chapter 629 of the Toronto Municipal Code, while complaints above 4 square metres go to Toronto Public Health [7]. Note that this 4 square metre referral line is a municipal enforcement threshold and does not match the remediation level thresholds below. Two different systems, two different numbers, and confusing them produces the wrong scope.

The Three Levels of Mould Remediation

In short: Ontario practice classifies mould work into three levels by contaminated area, and the level drives containment, protective equipment, oversight, and cost far more than the mould species does.

The framework Ontario relies on comes from the Environmental Abatement Council of Ontario’s Mould Abatement Guidelines, Edition 3, published in 2015 [4]. It is guidance rather than law, which is exactly why competent contractors follow it. The City of Toronto adopted it for its own owned and leased facilities, and Ontario’s workplace guidance points employers toward the same body of work [1][3].

Levels are set by the size of the affected area, and that extent is usually established by visual inspection [3].

Level	Description	Affected area
Level 1	Small isolated area	1 m2 (10 sq ft) or less of building materials, or under 1 m2 of growth in HVAC systems in non-occupied areas
Level 2	Medium area	1 to 10 m2 (10 to 100 sq ft), or under 1 m2 in HVAC systems in occupied areas
Level 3	Large area, or more than 1 m2 in HVAC	Over 10 m2 (over 100 sq ft), or over 1 m2 in HVAC systems

Source: City of Toronto Mould Management policy, based on EACO Mould Abatement Guidelines 2015 Edition 3 [3][4].

Two details in that table carry real weight for commercial buildings. The HVAC thresholds are far tighter than the building-material thresholds, because ventilation systems distribute spores through occupied space. One square metre of growth inside an air handler moves a project to Level 3, the same tier as over 100 square feet of contaminated drywall [3]. And occupancy changes the classification: the same small patch in HVAC serving an occupied area lands at Level 2 rather than Level 1 [3].

The City’s own policy sets an oversight expectation worth borrowing. Qualified consultants are retained to inspect and monitor projects classified Level 2 or higher, and air sampling follows Level 2 or higher abatement to check whether the procedures worked [3]. If Toronto applies that standard to its own buildings, a private commercial owner has a reasonable benchmark to hold a contractor to.

Signs of Mould in a Commercial Building

In short: Visible growth is the obvious signal, but in commercial buildings the earlier signals are usually a smell, a stain, or a cluster of occupant complaints from one zone.

Most mould in a commercial building is found late, because the places it starts are the places nobody looks. Mould is most often confined to areas near the water source [1], which means the search starts with the leak history rather than with the complaint.

Signals that warrant a look:

• A persistent musty or earthy odour, strongest near return air grilles or in a specific zone
• Water stains or discolouration on ceiling tiles, drywall, or below window sills
• Peeling paint, bubbling wall coverings, or drywall paper that separates when pressed
• Efflorescence or dampness on below-grade walls and slab edges
• Warped baseboards, lifting vinyl tile, or soft spots in subfloor
• Indoor air quality complaints concentrated in one part of the floor plate
• Any water episode from the past several months that was never logged or verified as dry

Hidden mould and how it gets found

Behind drywall, above ceiling tiles, inside wall cavities, and within duct interiors are the four places commercial mould hides. Finding it is a moisture-mapping exercise: thermal imaging to locate temperature anomalies, pin and pinless moisture meters on suspect assemblies, borescope inspection of cavities, and relative humidity readings across zones. None of that requires a lab.

One practical control the City of Toronto builds into its own program is a water episode log, a running record of every leak, spill, seepage, and flood, with corrective action tracked against each entry [3]. Commercial operators who keep one find hidden mould earlier and defend their diligence better.

Does Your Building Need Mould Testing First?

In short: Usually not. Ontario’s own municipal policy states sampling is not required to start remediation or set the level, and Health Canada does not recommend mould testing in office buildings and schools.

This section corrects the most expensive myth in this market. Many Toronto providers position air or surface testing as the mandatory first step, and quote the remediation only after the lab report comes back. The authorities say otherwise.

The City of Toronto’s Mould Management policy states directly that air and surface sampling are not required to undertake remediation or to determine the mould remediation level, and that the extent of contamination is usually based on a visual inspection [3].

Health Canada goes further. It has no numerical health-based exposure limit for indoor mould, because the number of mould species and the variation in how individuals respond rule out deriving one [5][8]. As a consequence, neither Health Canada nor the US National Institute for Occupational Safety and Health recommends testing for mould in offices, schools, or non-industrial buildings [5]. Health Canada also notes that interpreting air sampling results takes considerable expertise, that the results may not reflect whether a problem exists, and that they are typically of little to no value when building a remediation plan [5].

There is a related point about species. Health Canada’s recommendations to control humidity, repair water damage, and clean visible or concealed growth apply regardless of which mould species is found [8]. Colour does not identify species, and species identification does not change the response. A lab report naming an organism rarely changes what has to come out of the wall.

When testing does earn its place

Testing is not useless. It is misplaced as a gate at the front of the job. It has genuine value:

• As post-remediation verification after Level 2 or higher work, which the City of Toronto builds into its own program [3]
• When an insurer, a tenant dispute, or a real estate transaction requires third-party documentation
• In healthcare, long-term care, or research settings with immunocompromised occupants, where a qualified consultant sets a project-specific protocol
• When occupant complaints persist after remediation and the cause is unresolved

The Commercial Mould Remediation Process

In short: Every credible commercial remediation runs the same arc: assess and map moisture, contain, remove and clean, filter the air, fix the water source, then verify and document.

Impact Restore runs a six-step process on commercial and industrial sites [9]. Each step below maps to the guidance in Ontario’s adopted framework.

• Site assessment and moisture mapping. Establish the extent of contamination visually, trace the water source, and set the remediation level [3].
• Containment setup and PPE protocol. Isolate the work area, and shut down the HVAC system serving the floor or area being remediated so the system does not distribute spores [3]. Notify affected occupants of the work plan, timeline, and precautions [3].
• Mould removal and HEPA vacuuming. Porous materials such as ceiling tiles, insulation, and wallboard affected by unsanitary water are removed and discarded. Non-porous and semi-porous materials that are structurally sound can be cleaned with a mild detergent solution and reused [3]. Dry sweeping is not permitted, and only HEPA-filtered vacuums may be used [3].
• Air filtration and decontamination. HEPA air scrubbers capture airborne spores while the work proceeds. Work stops if containment is breached, and barriers are resealed before restarting [3].
• Moisture source correction and material replacement. This is the step that determines whether the mould comes back. If the underlying moisture is not rectified, growth recurs [3]. Where elevated humidity is the driver, relative humidity is brought below 60% [3].
• Final testing and clearance documentation. Evaluate the work, and issue the record the building owner needs.

The biocide question

A point worth raising before signing any quote. Toronto’s policy advises against applying disinfectant to mould-damaged materials except in cases of extensive microbial contamination such as sewage backflow [3]. The reasoning is specific: biocides in that role pose health concerns for workers and for people in adjacent occupied spaces, they do not address the health concerns from remaining non-viable mould, and liquid application can leave moisture in porous materials that seeds new growth [3]. The policy also advises avoiding unnecessary sealants and coatings that may affect occupants [3].

So when a quote leads with fogging, antimicrobial treatment, or a mould-resistant encapsulating coating in place of physical removal, that is worth a direct question. Removal and drying do the work. Chemistry is a supporting act with a narrow indication.

Clearance, Documentation, and the PRE Versus PRV Distinction

In short: A contractor checking its own work is an evaluation, not a verification. Verification means an independent third party signed off, and that difference is where most clearance documentation falls apart.

The 2024 fourth edition of the ANSI/IICRC S520 Standard for Professional Mold Remediation, which superseded the 2015 third edition, draws a line that commercial buyers should know [6]. Post-remediation evaluation is the remediator’s own internal quality-control check that the work is complete and effective. Post-remediation verification is a verification only when an independent third-party indoor environmental professional performs it [6].

Both have a place. Only one of them is independent. When a Toronto commercial building needs documentation that will survive an insurance review, a tenant challenge, or a regulator’s question, the independent version is the one that carries weight. The City of Toronto’s practice of retaining qualified consultants to inspect and monitor Level 2 and higher projects reflects the same logic [3].

A complete commercial clearance package should include the moisture readings taken at assessment and at completion, photographic documentation of containment and removal, drying logs, the scope of work performed, disposal records, the corrective action taken on the water source, and any post-remediation sampling results with the name of the party who collected them.

What Drives the Cost of Commercial Mould Remediation in Toronto

In short: Published per-square-foot figures for Toronto are mostly residential and range so widely that they are not a planning basis for a commercial building. Scope drivers give a better estimate than any single number.

An honest answer here is more useful than a fabricated one. Published 2026 cost guides for the Toronto area quote figures that disagree with each other by roughly a factor of eight on a per-square-foot basis, and nearly all of them price residential attics, basements, and bathrooms. None of that transfers to a 40,000 square foot warehouse with a contaminated air handler, and no primary source publishes commercial remediation pricing for this market. Any Toronto page quoting one confident commercial number is guessing.

What can be described accurately is what moves the number. In rough order of impact:

• Remediation level. Level 1, Level 2, and Level 3 differ in containment, negative air equipment, protective equipment, worker numbers, and oversight [3].
• HVAC involvement. Contamination inside air handling systems escalates the level quickly and adds duct access, cleaning, and component replacement [3].
• Whether the water was clean or contaminated. Sewage or other unsanitary water means porous materials must be discarded rather than cleaned [3].
• Designated substances in the work area. Asbestos or lead in the same assembly triggers a separate regulated scope before mould work proceeds [3][10].
• Occupancy and access. Phased work, after-hours scheduling, and keeping adjacent tenant space open all cost more than an empty building.
• The moisture source repair. Roof work, foundation work, plumbing, or air handling repairs are separate from remediation and are frequently omitted from the low quote.
• Reconstruction. Putting the wall, ceiling, and finishes back is a construction cost, not a remediation cost, and it is often the larger half.
• Independent verification. Third-party consultant fees for Level 2 and higher work [3][6].

The practical move is to get scope-specified quotes at a defined level with the moisture repair and reconstruction priced separately, so the comparison is like for like.

How Long Commercial Mould Remediation Takes

In short: Emergency response should be same-day, but total duration depends on the level, the drying time for wet structure, and whether reconstruction follows.

The response clock matters more than the total clock. Mould begins growing on wet building materials within 24 to 48 hours, so drying that starts on day one prevents work that would otherwise take weeks [3]. Toronto’s own policy targets drying initiation within 24 to 48 hours of a leak, flood, or water intrusion [3].

Impact Restore commits to arriving on site within two hours or less across the GTA, with published bands of 30 to 60 minutes for the Toronto downtown core, 45 to 75 minutes for North York, Etobicoke, Scarborough, and York, 60 to 90 minutes for Mississauga, Vaughan, Brampton, Markham, and Richmond Hill, and 90 to 120 minutes for the extended GTA [9].

After that, the honest framing is a sequence rather than a fixed number. Assessment and level classification happens on the first visit. Containment goes up next. Removal duration scales with the level. Structural drying continues until moisture content targets are met, which equipment cannot rush past the physics of the material. Independent verification is scheduled after removal and drying are complete. Reconstruction follows, on a construction schedule. A Level 1 patch can finish inside a day. A Level 3 project with a wet structure and reconstruction runs on a multi-week schedule, and any contractor promising a fixed date before assessing the moisture has not looked closely enough.

Mould in Commercial HVAC Systems

In short: Ventilation systems get the tightest thresholds in the entire framework, because they move spores through occupied space faster than any other pathway.

The numbers make the priority clear. Under 1 square metre of growth in HVAC in a non-occupied area is Level 1. The same amount in an occupied area is Level 2. Over 1 square metre anywhere in HVAC is Level 3, alongside contamination over 10 square metres of building material [3]. A patch small enough to be trivial on a wall is a major project inside an air handler.

Where it starts: cooling coils and drain pans that stay wet, humidifier sections, filter racks running past their change interval, insulated duct liner that got wet, and any duct downstream of a roof leak. Toronto’s own program calls for periodic routine inspections of HVAC equipment by a qualified person [3], which is a reasonable standard for any commercial operator to adopt.

Two operational notes. Shut the affected system down during remediation so it stops distributing spores [3]. And in long-term care settings, Ontario’s Health Care and Residential Facilities regulation requires inspections at least once every six months, with results provided to the joint health and safety committee [3].

Preventing Recurrence

In short: Prevention is a moisture control program, not a cleaning program: keep relative humidity under 60%, dry water episodes inside 48 hours, log everything, and inspect on a schedule.

Remediation that does not fix the water is a deferred repeat. Ontario’s framework is unambiguous that the underlying cause of the moisture intrusion must be rectified or growth recurs [3].

A workable commercial program has five parts:

• Humidity control. Hold indoor relative humidity below 60% [3]. Watch below-grade levels and shoulder seasons, when air handling systems are neither heating nor cooling much.
• A 48-hour drying rule. Treat every leak, spill, seepage, and flood as a clock that starts immediately, with drying initiated within 24 to 48 hours [3].
• A water episode log. Record each event, the corrective action, and the verification that the assembly dried. Toronto runs its own facilities this way [3].
• Scheduled inspection. Periodic inspections by a qualified person, covering signs of water intrusion, damp or damaged materials, visible growth, and HVAC equipment [3]. Increase the frequency after any mould incident to confirm the fix held [3].
• Envelope maintenance. Roof drains and flashing, foundation grading and waterproofing, window and curtain wall seals, and insulation on cold lines.

Choosing a Mould Remediation Company in Toronto

In short: Ontario does not license mould remediators, so credentials, standards fluency, and documentation practice are the only real screening tools.

Start with a correction. Ontario has no licensing regime for mould remediation contractors, so any firm advertising itself as a licensed mould remediator in Ontario is using a word that does not describe a real provincial credential. The verifiable credential in this trade is certification, and the recognized body is the Institute of Inspection, Cleaning and Restoration Certification. Impact Restore states that all of its technicians hold IICRC certification [9].

Questions that separate serious commercial contractors from the rest:

• What remediation level are you classifying this project at, and what is the basis for that classification?
• Which standard or guideline are you working to? An Ontario commercial contractor should reference the EACO or EACC guideline and the current 2024 edition of ANSI/IICRC S520 without prompting.
• Are you performing your own post-remediation evaluation, or arranging independent third-party verification? [6]
• Have you reviewed the designated substances inventory for this work area? [3]
• What is your plan for correcting the moisture source, and is it priced in this quote or excluded?
• How will occupants be notified, and what will they be told? [1]
• What documentation will I hold at the end: moisture logs, photos, disposal records, clearance report?

Watch for three patterns. A quote that requires lab testing before it will price the work runs against Ontario’s own municipal policy and Health Canada guidance [3][5]. A scope built around fogging or antimicrobial coating in place of physical removal runs against Toronto’s biocide guidance [3]. And a US-framed pitch citing EPA approvals or OSHA rules signals a contractor who has not read the Ontario material, since disinfectants used in Canada carry Health Canada registration and the governing statute here is the OHSA.

Frequently Asked Questions

Is mould remediation regulated in Ontario?

There is no mould-specific regulation in Ontario. Employer obligations come from the Occupational Health and Safety Act, including the section 25(2)(h) duty to take every precaution reasonable in the circumstances, with duties also placed on constructors and supervisors [1][2]. Ontario Regulation 278/05 covers asbestos, not mould [10].

Do I need mould testing before remediation in Toronto?

Generally no. The City of Toronto’s Mould Management policy states that air and surface sampling are not required to undertake remediation or to determine the remediation level, since the extent is usually established by visual inspection [3]. Health Canada does not recommend mould testing in offices, schools, or non-industrial buildings [5].

How is the size of a mould problem classified?

By contaminated area. Level 1 covers 1 square metre (10 square feet) or less, Level 2 covers 1 to 10 square metres (10 to 100 square feet), and Level 3 covers more than 10 square metres, or more than 1 square metre inside HVAC systems [3][4].

Is black mould more dangerous than other mould?

Colour does not identify a mould species, and species identification does not change the required response. Health Canada’s recommendations to control humidity, repair water damage, and clean visible or concealed growth apply regardless of the species found [8]. Ontario’s guidance notes that the most common moulds are generally not hazardous to healthy individuals, while some moulds may be hazardous to certain individuals [1].

What are the reported health effects of mould exposure at work?

Ontario’s workplace guidance lists runny nose, eye irritation, skin rash, cough, congestion, and aggravation of asthma as the most common effects, notes that they usually resolve after exposure stops, and states that in most cases workplace mould exposure does not result in long-term health consequences [1]. People with asthma, bronchitis, hay fever, other allergies, or a condition affecting the immune system are more likely to experience effects [1]. Anyone concerned about their own health should speak with a health care professional.

How much does commercial mould remediation cost in Toronto?

No primary source publishes commercial mould remediation pricing for this market, and the published Toronto guides are mostly residential and disagree with each other by a wide margin. Cost is driven by remediation level, HVAC involvement, whether the water was clean or contaminated, designated substances in the work area, occupancy constraints, the moisture source repair, reconstruction, and independent verification [3][6]. Ask for a scope-specified quote at a defined level with the repair and reconstruction priced separately.

How quickly should we respond to a leak to avoid mould?

Mould can begin growing on wet building materials within 24 to 48 hours, and Toronto’s own facilities policy targets initiating drying inside that window after a leak, flood, or water intrusion [3]. Impact Restore’s commercial teams arrive on site within two hours or less across the GTA [9].

What is the difference between post-remediation evaluation and verification?

Under the 2024 fourth edition of ANSI/IICRC S520, post-remediation evaluation is the remediator’s own internal quality-control check, while post-remediation verification counts as verification only when an independent third-party indoor environmental professional performs it [6].

Should the contractor spray an antimicrobial or apply a mould-resistant coating?

Toronto’s policy advises against applying disinfectant to mould-damaged materials except in cases of extensive microbial contamination such as sewage backflow, because biocides used that way raise health concerns for workers and adjacent occupants, do not address remaining non-viable mould, and can leave moisture that seeds new growth [3]. The policy also advises avoiding unnecessary sealants and coatings [3].

Do we have to tell tenants and staff about the mould?

Ontario’s guidance states that occupants of buildings contaminated with mould should be advised of its presence and given information on the health effects of mould [1]. The City of Toronto’s policy also calls for notifying occupants of the remediation work plan, timeline, and required precautions [3].

Does mould in HVAC get treated differently?

Yes, and the thresholds are tighter. Under 1 square metre in HVAC in a non-occupied area is Level 1, the same amount in an occupied area is Level 2, and more than 1 square metre anywhere in HVAC is Level 3 [3]. The affected system should be shut down during remediation [3].

Can we keep operating while remediation is underway?

Often yes, depending on the level and the containment plan. Toronto’s own approach is to perform remediation after hours where feasible and to isolate the work area so adjacent space stays usable [3]. Impact Restore sets up containment zones designed to keep other areas of a facility open where possible [9].

Are mould remediation contractors licensed in Ontario?

No. Ontario has no licensing regime for mould remediation contractors, so certification rather than licensure is the credential to verify. The recognized certifying body in this trade is the IICRC, publisher of the S520 standard [6].

What documentation should we receive at the end of the project?

A complete commercial package covers moisture readings at assessment and completion, photographic documentation, drying logs, the scope of work performed, disposal records, the corrective action taken on the moisture source, and any post-remediation sampling results identifying who collected them.