Is my house at risk for mould? How do I reduce my mould risk?

Mould is the insidious, ever looming that every homeowner or every office worker fears. Every single house has mould spores, but it’s only an issue if the mould spores grow to a large enough number to start causing visible issues.

For those with already existing respiratory or immune issues, they fear it even more. Mould raises the risk of a variety of respiratory and asthma-related health outcomes by 30 to 50 percent, so it’s especially important not to let mould get out of control.

Hence, we here at Zenith Lab decided to put together this checklist of mould risk factors for your home, and we hope you’ll find it helpful.

1) An older house

If you’ve been living in your current place for a while or bought it second hand, your house may actually be predisposed to mould. At 22 years or more, your house is more likely to fall victim to mould. This is due to outdated insulation/poorer quality materials being used in the construction of your building.

How to fix this: Unless you’re due for a house upgrade soon, all you can do is keep a frequent eye on possible mould danger spots and call a mould professional if needed.

2. Previous water damage/frequent spills

Do frequent spills occur in your house? If not cleaned up quickly and thoroughly, they can quickly become not just a safety hazard, but a perfect habitat for mould spores to land and thrive. Cleaning up spills ensures that you won’t be greeted with unsightly mould stains on your floors.

Water damage generally refers to damage caused by flooding. While we generally do not suffer from floods or other natural disasters here in Singapore, flash floods (floods that come and go very quickly) are still a potential concern, as are water leaks that have gone unchecked.

How to fix this:

Conduct frequent spot checks on the ceiling and taps of your house, and have them fixed as soon as possible. It may not be cheap, but it saves you the even higher cost of hiring a mould removal professional or fixing extensive water damage.

For comparison, the cost of just drying out your property with little to no damage = $2500.

The cost of drying out your home and repairing the damage done to areas like drywall and carpeting = $7500!!

That’s three times the cost, which is really quite alarming.

3. Having a darkly lit house

If your house (especially HDB houses) tends to not get much sunlight through your windows, this may increase your house’s exposure to mould, especially in the darker rooms. Mould actually grows in both light and dark environments, but dark areas most often provide the ideal growing conditions for mould. According to the University of Illions, mould also tends to grow best in warm, humid environments Because of this, darkly lit areas are more often suitable for mould growth and expansion in part due to their lower temperature.

How to fix this:

Figure out which areas of your house tend to be the darkest or rarely lit. Common ones are storerooms (discussed in the next point), heavily curtained rooms, and kitchens.

4. You own a storeroom.

Unlike most rooms, you probably only visit your storeroom/ storage room when you’re looking for something older and decidedly dustier. That probably means that your storeroom is kept in pitch-black darkness 90% of the time, and is only opened once every few months, if even at all. To make things even worse, storage rooms rarely have windows or other things that would increase ventilation.

This severe lack of ventilation creates an environment that means mould spores are rarely cleared out of the room or have their growth interfered with, which is pretty much ideal mould growing conditions. It is dusty, humid, warm, and dark. That’s all mould really needs to thrive!

How to fix this:

Make the effort to open your storeroom door at least once a week and inspect the items inside. If something is obviously dusty and no longer wanted, don’t extend it’s stay and let it become a mould breeding haven.

5. Damp clothes or towels are a mainstay in your home.

If you’re the sort who tends to come home all sweaty after work or a jog and toss your clothes on the ground, you’re definitely not the only one who does this.

However, your laissez faire attitude when it comes to your laundry may actually be ruining their shelf life. Ever picked a shirt up off the floor and instantly noticed that nasty, mildewy smell? That is the beginning of mould..on your clothes. Nasty!

While it may not get to the point where you’re seeing actual mould stains on your clothes, that mildew smell should be enough to turn you away.

Before you ask, air freshener is not a viable solution to that nasty smell, nor is just living with it. Clothes with mildew may be causing your allergy symptoms (red eyes, cough, runny nose that won’t quit).

Besides, no one wants to be friends or coworkers with someone whose clothes smell terrible and make them cough.

How to fix this:

Wash all your laundry a tad more frequently than you currently do. If you want exact numbers, check out The Fashion Shop’s comprehensive guide on when to wash to prevent mildew smell on your clothes.

6. You neglect your bathroom.


You’ve probably heard more than enough about the likes of cleaning your room when you were younger from your parents, but not much on the bathroom.

Did you know that your dirty bathroom is one of the most common culprits when it comes to growing mould?

There’s a permanent water source (your toilet bowl and damp floors) in the bathroom, a below-average amount of light, and lots of humidity from using the shower. Not to mention, your shower curtain is a great place for all those mould spores to cling onto and breed.

How to fix this:

Clean your bathroom at least twice a week. While we all hate cleaning our bathrooms (the no.1 most hated core in America!), the ideal is cleaning the bathroom every single day. We think that cleaning the bathroom two times a week is a good compromise.

Spray down your toilet seat with a vinegar or bleach solution, and take a toothbrush to it to remove any visible mould or dirt. Also, replace your shower curtain every 9 months, more so if it starts looking visibly green or black.

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