• Melanie Evans

Cold Weather Mould Growth: What to Look for and How to Prevent It



Though you might not have thought so, the colder temperatures of fall and winter can easily - and quickly - increase the likelihood that mould will take hold somewhere in your home. It's a perfect storm type of both indoor and outdoor factors that lead to this less than pleasant scenario.


Mould is not something that any homeowner is happy about, but it is something that they sometimes overlook if there is not a lot of it, or if it is located in a rarely used space like an unfinished basement. Not an ideal way to think about it, but we do see it happen more often than it perhaps should.


Mould is a bigger problem if you are intending to sell your Waterloo Region home. As we mentioned, you don't want to take any chances with mould when it comes to your house, but at sale time it can become a deal killer.


Even if the mould problem is minor, would be homebuyers will be put off by unsightly spores that detract from the appearance of the house (and perhaps put its structural stability in jeopardy) and wonder about whether the mould will make them cough and sneeze once they move in.


Selling your mould-infested home will therefore necessitate that you deal with the issue head-on and make every effort to solve it, unless you want to agree to a price reduction or go through a string of buyers who ultimately back out of the transaction. Therefore, anything you can do to prevent mould in the first place is a big plus. As the colder months are coming, now seems like a great time to think about all of this, whether you are planning to sell your Waterloo Region home or not.


Mould Growth in Fall and Winter: Basic Facts


As soon as the temperatures start to drop, we all tend to start sealing up our homes and, in the interests of energy efficiency, sealing them up pretty tightly. Windows are closed and then maybe even resealed to keep the cold air out, the air conditioning goes off, and the heating goes on in its place and if anyone leaves the front door open for more than a few seconds they are likely to get (rightly) scolded for letting the cold in.


All of this is great, you and your family will be warm and happy. The problem is though that all of this creates lots of warm air that really has nowhere to 'escape' to leading to increased indoor humidity and condensation, two things that mould truly loves and thrives fantastically around.


Add this to the fact that outside mould is having a fabulous time breaking down all the dead plant matter, especially leaves, that is lying around (which is actually its real purpose in the grand scheme of nature) and so far more mould spores are in the air than at other times of the year and yes they'll find their way into your home; via shoes, that occasionally open door and even on your clothes.


Common Indoor Breeding Grounds for Mould in Fall and Winter




Mould growth in colder seasons is usually most commonly found on the exterior of drywall, sheet rock and other surfaces of rooms located in bends and corners of the home. As corner rooms are exposed to significantly colder air than their adjoining rooms, they will soon have higher relative humidity levels (RH) as well. However, the adjoining rooms have the same water vapour pressure, ultimately creating conditions that can can lead to some major mould growth in winter.


If you spot any mould growth in the colder months in such a corner room in your home, it may mean the RH of the next room’s surfaces is 70% or higher. On the other hand, if the temperature in the room is too cold, or there is a lot of moisture (high water vapour levels), the room may also have RH levels over 70%. Both the relative humidity and the temperature of the rooms’ surfaces and areas need to be balanced – neither too moist, nor too cool.


Simple Tips to Prevent Mould Growth in Winter:


Reduce Your Home's Humidity Level


Moist spaces support the growth of mould. Therefore, you need to keep your home dry to avoid this problem.


Keep an eye on the humidity levels indoors. For this purpose, you can install a hygrometer. The ideal humidity level to prevent mould growth is 60%. Make sure to look into where humidity is at its highest in a home. Bathrooms are often host to various moulds, and you should also often check for mould on windows and walls, as well as around the edges of tubs, toilets and sinks.


Wipe Down the Walls of the Bathrooms


When you take a shower or have a bath, water vapours accumulate on the walls of the bathroom, making them prone to mould infestation. After having a shower or bath, don’t forget to wipe down the walls with a clean and dry towel. It's an extra step, sure, but one that takes just a few extra minutes and can be very effective for minimal effort.


Make Sure Your Exhaust Fans are Adequate


Almost every bathroom has an exhaust fan, but often they are not quite up to the job, especially if the space is a busy family bathroom. Therefore, you should review whether yours is adequately sized to get the job done properly. There is an excellent piece here that goes through exactly how to do that.


You should also make sure that the fan is used at all times, and that other spaces, especially the kitchen, also have properly sized exhaust fans. If you cook a lot, the standard fan over the stove may not quite be enough to prevent mould growth.


Never Ignore Damp Clothes


Mould doesn’t only grow on the walls of your home, but damp clothes and furniture can also spread it. After doing laundry, never leave the wet clothes in the washing machine. As soon as you’re done washing them, move them into a dryer or dry them in your terrace or balcony.


Similarly, if you spill any liquid on a cloth, wash and dry it immediately, instead of leaving it lying around. This way, you can effectively prevent the growth of mould in your home.


Address Any Mould Issues Fast


If you do find mould in your home, whether you are selling it or not, you should address the problem immediately.


It may be tempting to remove mould on your own, for budgetary or for other reasons, but you should only make this attempt if the affected area is smaller than 10 square feet.


The do-it-yourself method involves a bleach mixture and small hand tools. There are also several ways to clean mould without harsh chemicals, including using vinegar, baking soda, and tea tree oil.


But DIY clean-up is typically not a long-term solution. This is because cleaning up mould, whether with bleach or another gentler solution, will only handle the mould growth—not the spores. After the area builds up a resistance to the homemade mixture, the mould will drink up any water you are feeding it.


Mold has a defensive reaction to remediation where it starts sending spores out when it is removed, leading to cross-contamination.


With larger jobs, the potential for cross contamination and contamination is serious. Therefore, removal is not recommended for amateurs. Removing mould is often a labor-intensive process, especially when the infestation affects the structural materials.


Additionally, having someone qualified to remediate the mould will save you money in the long run; ensuring someone will do the job correctly to preserve structural integrity.


If removed incorrectly, mould infestation can grow and become a very expensive project. Aside from the financial impact if structural damage occurs, or if a sale of your home is negatively impacted, the potential for bad health effects increase significantly when cross-contamination occurs.


Therefore, calling in a pro is a must in many instances, something that Team Pinto know all too well, as, prior to becoming one of the Waterloo Region's leading real estate agents, Aron owned and operated a remediation company that led him to see the harm mould can do far too often!






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