10 ways to avoid mould/water damaged buildings when hunting for a property

Keen to avoid mould/water damage in your next rental or purchase? While it’s not entirely possible short of inviting a mould technician, building biologist and remediator to the inspection to guarantee that you’re going to be getting a , there ARE a few signs something isn’t quite right. Naturally, you have more time on your side if you’re considering buying, but that’s absolutely not to say there aren’t some quick visual/smell cues you can’t look out for as a renter.

Being someone hit by mould illness myself –  (more on this here where I chronicle my entire story) I understand the importance of spotting these homes early, now, instead of living in one for a year and another for 8 years before realising the damage that a water-damaged building can cause to someone’s health! I’ve put together 10 things to look for when renting a house so you can work to minimise the chance of exposure to mould through a water-damaged building. 

But first, what is mould?

Mould is part of a group of very common organisms called fungi, including mushrooms and yeast. It is virtually everywhere, indoors and outdoors, but thrives in damp areas and water-damaged homes lacking adequate ventilation, including walls/ wallpaper, ceilings, bathroom tiles, carpets (especially those with jute backing), insulation material and wood. There are different species, and over time, science has discovered that the different types can impact us in different ways, from allergies to systemic inflammation to neurotoxicity to infection to carcinogenic impact. If you’re familiar with the basics on gut health and knowing that some pathogens exist happily in the gut and can even be useful in small colony size, but it’s when they proliferate and take over from the ‘good guys’ that they cause havoc, it’s essentially the same with mould. At low levels, kept in check by healthy environments, most species are part of a healthy functioning ecosystem, but allowed to proliferate, through damage to building materials, excess indoor humidity or poorly maintainted air conditioning ducting or reverse cycle units, they can cause havoc on human health – specifically a group of moulds that thrive in water-damaged buildings. My “So You Think You’ve Got Mould” has lots more on Mould, along with all the podcasts, blogs, and resources I’ve pulled together over the years, if you want to deep-dive on the illness front. 

Why should we be avoiding mould and water damage?

Water damage and dampness occur in buildings when a pipe or roof is leaking and/or a building has not been built with the correct ‘wet area’ foundations to enable optimal ventilation and drying. Or maybe it’s an old place, and the waterproofing at the base has broken down, and rising dampness is kicking in. Or maybe it’s excess humidity that isn’t being managed well with dehumidification – this is common when there are La Niña weather cycles or in coastal living or the tropics. Did you know, for example, that the East Coast of QLD/NSW is on average over 60% humidity for 4-8 months of the year, depending, and that 60%+ humidity + dust or natural/porous materials = perfect conditions for mould to grow? 

Recurrent water dripping or leaking in one place results in an excessively damp area, often hidden behind paint or foundation walls, under furniture, or in nooks and crannies of a building. If you’re fortunate – or unfortunate – enough to discover the actual site, it can be a pretty shocking and menacing-looking thing, and for our health, it often is. 

Once this icky, toxic mould is growing, it produces tiny particles called spores. Spores are carried through the air and may cause health problems if inhaled by people who are sensitive or allergic to them. Common symptoms look like an unexplained running or blocked nose, irritation of the eyes and skin, and sometimes wheezing. If you’re one of the unlucky folk who is highly susceptible to mould illness, your symptoms might be far more severe, like a racing heart, diarrhoea, nervous system issues, electric shock, migraines, mood swings, depression, joint and muscle aches and twitching and chronic unexplained illness… just to name a few. These more systemic, inflammatory symptoms stem from the mycotoxins and bacteria that the spores ‘cough’ into the air and it is thought by some scientists and doctors that a percentage of the population have immune function glitches that can’t see these as toxins and mount the appropriate response to them to bind and remove them from the body. 

10 things to look for when renting a house 

So now that you have a general understanding of why landing a good home is important, the bad news is, not everyone knows how to build a healthy home, maintain a healthy home, nor property manage to prevent damage. In fact, sometimes people actively seem to do the opposite and it can cause heart ache, grief, illness and financial stress. That’s a big fight to fight but at least to start we can all get better at knowing what we need to know to increase our chances of success.

Here are 10 key signs you want to look for when inspecting your next rental or potential home purchase. If you’re purchasing, you have a longer lead time, and in addition to a building report, I strongly recommend that a building biologist or mould technician review the prospective home and provide a report of their findings. This will cost 800-1500 for thorough sampling and inspection, usually, but could save you many thousands in repair, or worse, illness!

I should also add that if you live in a humid climate, mould prevention by keeping indoor humidity below 60% is very important, regardless of where you live or whether you’re buying or renting. Humidity management protects your possessions, your indoor building materials and prevents small problems from getting worse. I did a solo podcast on that very thing here. I also did a 10-part series on humidity management how-tos on Instagram if you scroll down a little to see the solid block of white-background tiles to help you learn how to be a humidity ninja, given that this is 50% of the mould issues out there, it’s estimated. That’s good news to me, because that is within our control. Getting a climate gauge is one of the best ways to monitor and understand the climate, and then back it up with a dehumidifier to reduce humidity. You have 10% off with AusClimate if you need either for your home. CODE: LOWTOXLIFE. That 10% code works across their whole site for Air Purifiers and their energy-efficient heating range, too.

1. Visible mould. Seems obvious, but it’s definitely the first red flag – if mould is visible, then chances are there’s far more hidden under the surface. Look behind cupboards, shine your phone torch into air vents/air conditioners, curtains (back and front), blinds, in the corners of rooms, in built-in wardrobes, around the edges of the bathroom, under all kitchen and bathroom sinks, behind couches, on windows and along window frames. Leave no stone unturned! Mould can appear as black, green, brown, or white spots, or as furry patches. Some people even find the odd mushroom – Run, don’t walk the other way! 

2. Broken pipes and downpipes around the building, under the sink or in the laundry area/bathroom/kitchen areas.  While you can’t see pipes behind walls, there is the opportunity to assess the health of visible ones on an inspection. The most common offender of these is plastic water supply lines to sinks and toilets, which newer buildings tend to use more. (Tip: Copper, which older buildings tend to use, almost never leaks. Galvanized steel is another sturdy material in this regard.)

3. Mildew (a surface fungus) is typically a grey or white colour – that can become black as the fungus grows. It’s commonly found in bathrooms and laundry areas as a result of poor ventilation.

4. Condensation, much like mildew, is an indicator of dampness. It looks like water running down walls, windows, or laundry surfaces. Condensation equals poor ventilation and means the building isn’t “breathing” properly. You’re left with a significantly increased chance of a damp indoor environment, especially if you’re going to be unable to leave windows open for long periods of time due to either weather or security.

5. Peeling or bubbling paint on walls. This commonly occurs as moisture is seeping between the hard wall surface and the paint. If you see this, it’s a cause for concern and definitely an indication that there is either rising damp or a broken pipe leaking behind the wall – check the walls on the other side of any bathrooms or laundry for this. Typically, the area above or below the paint will have a leak. 

6. A musty smell. Most moulds have a pungent, musty odour. If there is a strong smell in the property, it likely indicates mould, coupled with poor ventilation and dampness in the room. Go into the wardrobes and built-in drawers and have a good sniff around. If there is synthetically perfumed clothing in the wardrobe that could mask your mould-detecting nose, remove a drawer from the built-ins and sniff behind it (or get someone who isn’t prone to becoming ill to do so – my husband is our sniffer dog these days!). 

7. You experience allergy-like symptoms or a pounding heart or – I know it might sound weird – a tense tongue. A good indicator is your body’s physical response when you enter a room. If you have sinus issues, coughing, wheezing, a tight chest, asthma triggers, irritated eyes, metallic taste, shortness of breath or a racing heart – to name a few, then this is a sure-fire sign that this is not the home for you. Be calm, take a few deep breaths if you can so that you rule out any fear and anxiety being the culprit, and if you tune in and feel these symptoms without a shadow of a doubt, then walk on out and into the next inspection. 

8. Water stains on the exterior. If you notice that the exterior of the building has water patches or stains dripping down the wall, look for the root cause and question the real estate to find the source. Sometimes it’s just from rain or another tenant, but if it’s a continuous dripping stream of water, this is the ideal home for mould and damp to grow (especially if you live in a humid city or high rainfall area). Avoid!

9. Moss growing on outdoor or porous surfaces. If you can see visible moss growing from brickwork, this may not indicate that the building has a leak, but it definitely highlights that the house is in a damp location. Be very discerning here – if the home feels musty inside too – ie, if you bring a climate gauge and the indoor humidity is high or higher than the outdoor humidity, then you might have a mould risk here. 

10. Poor drainage. Check the gutters around the property – are they clogged, dirty or mouldy – or, always fun to see, is a plant growing out of the gutter? Clogged gutters mean drainage is not adequate and a cause for concern. If they can be cleared out, you might be ok; however, if the overall state of the home is not in good condition, AND the gutters are full, this is a red flag.  It’s a sign that the upkeep is poor and not prioritised, and you’ll face uphill challenges getting things that aren’t in good condition attended to. It can be a great idea to do a drive-by if there’s rain during the time you’re considering the home – water pooling around the base of the home or bogging the front garden, if there is one, is another big red flag that things get damp and stay damp there, thus mould is more likely to grow. 

Also worth considering… orientation and topography

Another bonus trick I’ve employed when searching for a new mould-free home is to avoid any apartments or houses at the base of a large hill, or in a part of a suburb shaped like the base of a valley, with hills rising from the area on all sides. Homes on slopes tend to be bigger traps for foundation issues and rising damp and/or homes that are shadowed in large bushland/trees overhead. Typically, these places experience higher water runoff during storm events, increasing the risk of pooling and water damage. I’m now living in a location that is raised from the ground, free of tropical-humidity-trapping trees and less susceptible to the weather with good guttering and drainage. It can be done! 

Aside from the visual cues you can look for at inspections, I highly recommend you arm yourself with some tools that you can take to do your own sneaky analysis when the real estate agent isn’t looking! 

I use the Hygrometer/climate gauge for testing humidity in the air space and the moisture meter for testing damp in walls. Both will give you a near-instant answer if you’re still unsure about a place. When we moved to one apartment years ago, hilariously, my husband distracted the agent talking cars in the living room, while I went on a full Mission Impossible inspection of the rooms. 

If you want to hear about my mould story you can listen to this podcast where I talk through the whole experience of moving from a water-damaged building a couple of years ago and how/what we cleaned and what we had to get rid of, sadly. There’s also my big aggregated post “So You Think You’ve got Mould” with lo9ts of resources and links.

If you’ve struggled with mould illness, you might like to check out my course, Inflammation Ninja, which I developed with 2 naturopaths, as a result of experiencing chronic inflammation after mould exposure, which has now helped hundreds of people who have lived with many different types of inflammatory conditions and illnesses. I know the feeling of feeling like it’s not possible that it will ever get better and everything hurts and there are scary symptoms in the mix. I also know the debilitating cost of testing and scanning everything and bouncing around on a million protocols, supplements, and trying medications because, hey, I’m open to anything that will move the needle for someone in SOS mode – I just don’t think finding answers and a path forward should be expensive for people. This was a huge part of my motivation in creating this one. If it’s found you at the right time, then yay!

Has this list helped? I’d love for you to share your experience of finding a healthy home below! 

If you’re buying a house and there’s one you’re really serious about? I’d test it with a Mould Technician or Building Biologist – get them to take a couple of samples – a mix of dust/air/swap in any room you’re not sure about, and test, don’t guess!

Low Tox. Healthy People. Happy Planet