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Getting sick from Mould in Apartments: What can be done?

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Mould in an apartment can be an incredibly complex problem for a tenant to deal with.  A great number of tenants call me to say that they are suffering serious health problems from Mould and that they can not get their landlord to fix the problem.  So what can be done? The presence of mold in a
rental unit is a relatively easy problem for a tenant to solve.  Getting compensated for injuries (health problems) that are caused by the presence and exposure to mould is much more difficult.  This article will focus on what a tenant can do to get mould problems fixed and deal only peripherally with the issues involved in proving a claim for injuries sustained due to the exposure to mould.  If I get enough questions about asserting mould claims for health problems I will tackle another article on that issue then.

When trying to fix a mould problem it is useful to understand the circumstances under which mould will typically grow.  In order for mould growth to thrive it needs moisture and high humidity, a medium to grow on (it likes porous materials), food,  heat and optimal temperatures (warm), and typically stagnant air.  Though mould will grow even in cool temperatures it is my experience that the majority of mould problems that trouble tenants arise in circumstances where warmth is a contributing factor to growth.   If you combine all of these factors it is quite likely that mould will not only begin to grow but flourish.  What kind of mould (from relatively harmless to toxic) will grow really depends on a great number of factors and specifically what kind of spores are in the environment.  However, in the presence of these factors you may reasonably expect that mould will grow as mould spores are all around us both inside and outdoors.  If the "right" conditions are created then mold will grow as the spores are around us.

The ability of a tenant to get rid of mould that is growing in a rental unit is tied to the ability to disrupt the moisture, growth medium, temperature and stagnant air that is encouraging the mold growth.  If these factors are disrupted it is entirely likely that mould growth will stop.  Unfortunately this does not mean that all of the mold that has grown will disappear from items that were covered in mould.  Mould likes to grow on pourous materials and these materials---including clothing, couches, beds, flooring, are sometimes impossible to clean of the mould that has already grown on them.  Often enough, these items simply have to be disposed of as it is impossible to clean them or too costly to do so.

Mould does not grow well in locations where there is a lot of air movement, where the relative humidity is low (under 50%), where the temperatures are cooler and nearer to regular room temperature and where the things that it would grow on are cleaned regularly. Changing one or all of these factors can have a dramatic impact on stopping mould growth.


Some of the things that encourage mould growth are typically within the control of a tenant.  Where a thermostat is adjustable the temperature can be kept in a range that does not encourage mould to grow.  Where the environment within a rental unit is conducive to mould growth because of the tenant's lifestyle choices--such as lots of hot showers, not wiping down walls and floors, cooking a lot things that puts humidity in the air then the tenant needs to try to take steps to deal with those choices in such a way as to disrupt the mould friendly environment.  What can a tenant do?  Suggestions that I have seen in the past include: appropriately opening windows, turning down thermostats, wiping and drying walls and wiping places where mould grows with vinegar water, installing dehumidifiers, ceasing activities that encourage mould growth and using fans to circulate the air.  Where mould is growing in cupboards or closets or along the back walls of storage areas the primary culprit seems to be the lack of air circulation.  Getting items away from walls, opening the doors or even installing vents can help move air around thereby impeding mould growth.


What can a tenant do if the things within the control of the tenant are "normal" and the mould still grows?  In these circumstances the responsibility for dealing with mould growth needs to be shifted to the landlord.  One would hope that a simple phone call or filling out a work order would result in the landlord attending the unit, figuring out the source of the problem, and addressing it.  Unfortunately, it is not always so simple.

Sometimes mould grows because the factors that encourage its growth (moisture, food, heat, stagnant air) are present because of a breakdown of a building system.  What does this mean?  Examples would include water infiltration through foundation walls due to a crack occurring, or water entering the structure through a failing/leaking roof, blocked eavestroughs, leaky pipes and plumbing.  Sometimes, the problem lies in a breakdown of the HVAC system and parts of the system are broken.  The point is that the occurrence of mould can be the result of a breakdown (rotting wood in basements, exposure to the ground) in the building structure or in the mechanical systems in the building.  Unfortunately, these breakdowns can be incredibly expensive to fix and therefore the landlord may resist doing the necessary repair.

If a foundation has cracked and it is allowing water to enter the building the landlord may be faced with excavating the foundation to effect a repair or perhaps undoing a finished basement to get at the walls.  Roofing can be expensive to replace or repair and sometimes the trick lies in finding the source of leaks.  As anyone who has watched Holmes on Homes knows, and you have likely seen those scenarios where the source of the problem is an improperly constructed home in the first place, sometime the only answer is an extensive re-engineering and rebuilding of the premises.

Repairing or fixing the things that cause mould growth can be so expensive that a landlord would prefer for the tenant to simply live with it.  The solution that a landlord may propose is that the tenant wipe the walls more frequently and open a window notwithstanding that the mould continues to grow and the tenants begin to feel like the mould is affecting their health.  How do you force a landlord to deal with mould when they really don't want to do it?


The first step that I always recommend to tenants is to speak with the landlord.  If that does not work, then a tenant should start writing letters to the landlord setting out the complaint, explain exactly what the problem is, and attach pictures if possible.  These complaints should be delivered in writing via email or fax or in such a way that delivery can be proven.

Once the complaints have been made, and presumably no response has been received, a tenant should call the Property Standards Department of their city, town, or township and ask them to come to the property to inspect the unit.   The Property Standards Officer will typically state that they do not have any specific mandate with respect to mould from a health perspective.  While that may or may not be true, the Property Standards Officer does have a mandate to ensure that a building complies with the Property Standards By-law of the city/town/township.  Note that for unorganized areas the RTA has a regulation that imposes a property standards type of standard for rental units (O.Reg 517/06).

Every Property Standards By-law that I have ever seen provides sufficient tools for a Property Standards Officer to query and require the rectification of problems that give rise to the growth of mould.  A Property Standards Officer can make orders with respect to water infiltration and moisture presence in a rental unit (where that moisture is not the result of tenant lifestyle).  A Property Standards Officer can deal with ventilation, cleaning of walls, repair of roofs, foundations, etc..  The point is that the things which encourage the growth of mould are things that fall within the purview of a properly constructed and maintained property and as such the tools to deal with these issues are available to the Property Standards Officer.

You may expect that a Property Standards Officer, when responding to an issue about mould will conduct an inspection of the premises looking for these kinds of things:  roof failure, penetration of roof, roof drainage system (pooling etc.), gutters (eavestroughs), downspouts being blocked, inspect vents, flashing, skylights, chimneys and anything else penetrating the roof.  The Officer will also look at cladding, flashing and trim on the walls of the building, exterior doors, windows, decks, stoops, steps, stairs, porches, railings, eaves, soffits and fascia to see if any of these things are failing or damaged and allowing water infiltration.  Of further interest will be the grading of the land around the property and any features that are directing or keeping water close to the building.

With respect to the basement and foundation that Officer will inspect all visible portions for damage (cracks) and signs of water infiltration and in crawl spaces the officer will look for adequate ventilation.  Ventilation is of general concern as well and the officer may look at the HVAC system including the air handler, circulating fan, air filters and any duct work in the premises.

Plumbing is also an obvious source of moisture so the officer will likely inspect any visible water lines, supply lines, waste lines and drains, the hot water source and the fixtures including the toilets, faucets, showers, and tubs.  There are other parts of the building (attic) that may be inspected and often it is simply the officers experience and the nature of the problem that will guide and direct the officer to the likely problems.  Where no problem is apparent, but mould exists, the officer may consider ordering a landlord to open walls to inspect for problems if the officer is satisfied that all other reasonable steps have been taken to control the mould.

It has been my experience that most Property Standards Officers, especially the experienced ones, tend to be practical about things.  They are solution oriented and before making orders requiring destructive testing or expensive renovations they will inquire whether the more traditional things have been tried---i.e., ventilation, opening windows, dehumidifiers, adjusting temperature.  Especially in rental units where there hasn't been a history of mould problems a Property Standards Officer is going to be cautious about making "expensive" orders unless of course the reason for mold growth is obvious and apparent (i.e. something broken and needing repair).


A tenant is entitled to file an application to the Ontario Landlord and Tenant Board requiring a landlord to fix or repair a rental unit.  Those repairs or maintenance are required to bring the rental unit up to the standard where the unit is fit for habitation.  The standard is reflected in section 20 of the RTA which provides as follows:

20. LANDLORDS RESPONSIBILITY TO REPAIR---(1) A landlord is responsible for providing and maintaining a residential complex, including the rental units in it, in a good state of repair and fit for habitation and for complying with health, safety, housing and maintenance standards.

(2)  SAME---Subsection (1) applies even if the tenant was aware of a state of non-repair or a contravention of a standard before entering in the tenancy agreement.

This section of the RTA imposes the legal duty on the landlord which is the basis for an application to the Landlord and Tenant Board under section 29 & 30 RTA.

There are certain assumptions that I assume will be adopted by any adjudicator hearing a case.  That assumption is that the presence of significant mould (readily visible) in a rental unit, on the walls, flooring, ceilings, etc. is contrary to the requirement that a rental unit be "fit for habitation".   It is generally accepted that a rental unit in Ontario is not fit for habitation if it has uncontrolled and significant mould growth within the unit.

Proving the presence of mould is also fairly easily done by taking photographs of the walls, floors, ceilings, or wherever the mould is located.  Some people will argue that black marks on the walls, floors, ceilings are not proof of the presence of mould as one can only know that it is mould if it is tested by a certified lab.  While that may be technically true, I have never known the argument to carry much weight when a tenant testifies that the mould has recently appeared, can be wiped off with a rag, and that it grows back again seemingly out of thin air.  The argument is that whether it is mould or not, anything that grows on a wall and re-appears after being cleaned, is something that is not "normal" and therefore is inconsistent with a rental unit that is "fit for habitation".

The value of having approached the Property Standards Department about mould is that the reports of a Property Standards Officer, along with any Orders, are extremely useful as evidence of the condition of a rental unit.  The "fit for habitation" standard certainly includes compliance with the requirements of the Property Standards By-Law and therefore, any Order directing that repairs be made in relation to mould will be evidence of the Landlord's breach of its duty to maintain a rental unit.

While getting a Property Standards Order is very useful it is still possible to proceed without such an Order or without even trying to get Property Standards involved.    However, without this very useful evidence from Property Standards the tenant will have a higher burden in proving that the rental unit is not fit for habitation and that certain work needs to be done to fix the unit.   This burden may be discharged by hiring experts, contractors, mould remediators, to prepare reports describing what is observed, what the problems are, and what needs to be done to fix the problem.  These reports will need to be backed up with oral testimony at a hearing.  Further, as the old saying goes, a picture is worth a thousand words and no hearing would be complete without high resolution photographs and perhaps video of the problems---including the mould and repair issues that are allowing the mould to grow (i.e. water infiltration, etc.).

An important point to note is that getting the Board to order the fixing of issues that are allowing mould to grow does not require the tenant to prove that the mould is causing health problems.  The mere presence of significant mould in the unit is unacceptable and in my experience the Board will Order it to be removed, cleaned, and the issue that is allowing the mould to grow to be repaired.

In my experience, the reason that tenants have difficulty winning mould cases is that not enough thought is given to discharging the burden of proof.  Many tenants are so disgusted by the presence of mould, and having a picture in hand, that they think showing the picture of mould is enough to win their case.  They think that by showing a picture of mould on a wall and saying that this has been there for months that this will be enough to win an Order requiring a Landlord to fix/remove the mould and for an abatement of rent.  The fact is, this is not sufficient to discharge the burden.


A tenant must demonstrate that they tried to deal with the mould.  They must demonstrate that they tried to adjust their lifestyle (reasonably) to address mould growth.  It is reasonable to expect that a tenant would try to wash walls, open windows, install a dehumidifier and operate a fan.  Be ready to prove that these things were tried.  Then, be ready to prove that the landlord was given notice of the problem, repeatedly, and that the landlord had specific knowledge of what the complaints were and the impact of the presence of this mould on your use and enjoyment of the property.  Then, be prepared to prove to the extent possible the reason for why the mould is in the rental unit.  While this should not be your obligation, it is indeed necessary as the Landlord will likely try blame you for the presence of the mould if no explanation for the presence is provided----so, show the broken pipe, hole in the wall, curling shingles, hole in roof.  If you have lost property as a result of the mould be prepared to show that property in pictures, provide the cost of acquisition (receipts) and estimates for repair or replacement.  Depending on what the item is, it may be important to get an appraisal from a recognized appraiser of the value of the item at the time of loss.

If you do these things--which is a lot more than just showing a picture of mould, you should have success at the Landlord and Tenant Board in getting an order fixing your mould problem.

Michael K. E. Thiele 


This post first appeared on Ontario Landlord And Tenant Law, please read the originial post: here

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Getting sick from Mould in Apartments: What can be done?


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