WOLLONGONG MOULD REMOVAL SERVICES
Bathroom and Ensuite Mould Removal in Wollongong
If your bathroom mould keeps coming back, your exhaust fan is probably venting steam into your roof instead of outside
Trusted Bathroom Mould Removal in the Illawarra, NSW
You’ve done the vinegar. You’ve done the bleach. You’ve stood on a chair with a toothbrush going at the grout, and for a fortnight the ceiling looked great. Then the black speckles crept back over the corner above the shower, and now they’re heading for the light fitting.
That’s not you being bad at cleaning.
In most older Illawarra bathrooms we look at, the exhaust fan isn’t sending steam outdoors. It’s pushing it up into the roof cavity, where it meets the cold underside of the roof, condenses, and comes back down through your ceiling. Twice a day, every day. You’ve been scrubbing the ceiling while the roof above it gets steamed.
Until 2022 that was allowed under the building code, as long as the roof space was ventilated. The National Construction Code changed that year, and exhaust from a bathroom now has to discharge to outdoor air rather than into the roof space. Homes built or renovated before the change were never made to catch up, and most haven’t. The Illawarra is full of those homes.
Fifteen years working on local bathrooms, and it’s the most common thing we find at Wollongong Mould Cleaning & Removal. It’s also fixable.
Sound familiar?
- Black spots on the ensuite ceiling that return within weeks of cleaning
- Mould in the grout and silicone around the shower that's gone grey or black and won't scrub out
- A musty smell in the bathroom even when it looks clean and dry
- Mould creeping past the bathroom, onto the hallway ceiling or the bedroom wall next door
- A bathroom with no window, or one you can't open in winter
- An exhaust fan that's noisy, weak, or that you're not convinced does anything
- A rental where the mould keeps returning and nobody will say whose problem it is
Send us a photo of the worst spot. We’ll tell you what’s likely driving it, and whether you even need us.
FREE INSPECTION, NO OBLIGATION
We will call you back personally to arrange a time.
When You Should Clean It Yourself, and When You Shouldn't
Most mould companies will tell you never to touch it. We’re not going to, because it isn’t true, and you’d work that out the first time you wiped a patch off and it stayed gone.
Clean it yourself when it’s a small patch of surface growth on tile, glass or painted wall, it wipes away, and it stays away for a couple of months. Gloves, a P2 mask, window open. That was a cleaning job and you’ve just done it for the price of a spray bottle.
It’s worth calling us when:
- It comes back: Recurring mould is a moisture problem wearing a cleaning problem’s clothes. You can scrub that ceiling every month for a decade and it will keep returning, because scrubbing changes nothing about what’s wetting the room.
- It’s in the silicone or the grout: Both are porous. Once mould has rooted down inside them, no cleaner reaches it. Bleach black silicone until it looks white and it will darken again in a fortnight, because the growth is still in there. That silicone has to come out and be replaced, not cleaned.
- It’s spread past the bathroom: Growth on the hallway ceiling or the wall of the next room means moisture is moving through the building, not sitting on a tile.
- It’s a big area: Scrubbing a large patch without containment throws spores through the rest of the house, and then you’re cleaning bedrooms.
If the trouble is mostly overhead, ceilings have their own quirks and we cover them on the ceiling mould removal page.
How We Remove Bathroom Mould and Stop It Returning
- We check the fan before we touch the mould
Where does it actually vent? Is it moving any air at all? The Code sets 25 litres a second as the minimum for a bathroom and plenty of older units fall well short. Almost nobody starts here, and it’s the step that decides whether you’re ringing someone again next winter. - We test for damp behind the surface
Moisture meters and thermal imaging across walls and ceiling, so a leak or failed waterproofing gets found rather than assumed to be condensation. - We contain the room
Sealed off, HEPA filtration running, so what comes off the ceiling doesn’t settle in your bedrooms.
We remove the growth properly. Surfaces treated and cleaned, not painted over. Silicone and degraded grout that’s been colonised comes out, because cleaning it buys you about two weeks. - We fix the cause
The fan, the sealing, the waterproofing, or the leak, depending on what turned up. More on that next. - We tell you how to keep it away
Specific to your bathroom, not a generic list. If you want to read ahead, it’s on our mould prevention page.
We Don't Stop at the Ceiling. We Go After the Fan
Every mould company says it finds the root cause. Almost none of them will tell you what the root cause usually is. So here it is.
The fan vents into the roof
The big one, and the reason it’s at the top of this page. Steam has to go outside. If the ducting stops short in the roof cavity, or there’s no ducting and the fan just blows into the ceiling void, you have a moisture problem that cleaning will never touch.
The fan is too weak
25 litres a second is the Code minimum for a bathroom. A tired unit from the 80s can sit well under that, which makes it roughly decorative.
The fan is choked with dust. A clogged grille moves almost no air. Plenty of people have a fan that runs and does nothing.
The fan goes off with the light
It needs about ten minutes after you’re finished to clear the humidity. Flick it off on your way out and it’s barely started. Newer installs are required to have a run-on timer for exactly this reason.
The bathroom silicone has failed
Water gets in behind it, sits in the wall, and feeds growth you can’t see from inside the room.
Here’s the part that matters. Reducting a fan to vent outside is an electrician’s job, sometimes a roofer’s as well. Most mould cleaners will write “improve ventilation” on a report and leave you to go and find those trades. We bring in the licensed tradespeople and stays your one point of contact, so the diagnosis and the fix are the same phone call. If the fan is the problem, we can get the fan sorted.
Bathroom Mould in Rentals, Units and Older Illawarra Homes
- Renting? If the mould comes from a building fault, like a fan venting into the roof, a leak, or waterproofing that’s given up, that’s generally the owner’s responsibility to fix under NSW tenancy law. If it’s from the room never being ventilated at all, it can fall to the tenant. The cause is what settles it, which is why having it identified in writing is worth something. Report it to the agent in writing with photos and dates (we ALWAYS recommend this as a minimum), and check your position with NSW Fair Trading.
- Landlords and property managers. A bathroom that gets “cleaned” every time a tenant complains is a bathroom you’ll hear about again in three months. Finding the cause once costs less than repainting a ceiling every year, and it leaves you a written record if things escalate.
- Units and apartments. An internal bathroom with no window has the fan doing all the work on its own. If it’s poorly ducted, or shared through a common riser, the moisture has nowhere to go. We’ll tell you when it looks like a building issue for strata rather than something inside your walls.
- Older homes. Small window, original fan, and a roof cavity treated as somewhere steam could go and be forgotten. If your bathroom is from the 70s or 80s and hasn’t been touched since, it’s very likely working against you.
If the mould traces back to a leak, a burst pipe or storm water rather than shower steam, that becomes water damage restoration.
How Much Does Bathroom Mould Removal Cost?
Two separate numbers here, and most companies blur them into one. There’s the cost of getting the mould out, and there’s the cost of fixing whatever caused it. You can’t understand your quote until you can see both.
The mould inspection is free either way, so finding out which bucket you’re in costs you nothing.
Removing the mould
| What you need | What it covers | Cost |
|---|---|---|
| On-site inspection | We check the fan, test for damp and tell you what’s actually causing it | Free |
| Small patch, surface only | A few tiles or one corner of ceiling. Often a job you can do yourself | $100 to $300 |
| Full bathroom treatment | Contained removal, HEPA filtration and antimicrobial treatment of the whole room | $500 to $1,000 |
| Spread beyond the bathroom | Growth into the hallway, adjoining rooms, wall cavities or the roof space above | $1,000 to $4,000+ |
| Lab testing (rarely needed here) | Samples to a NATA-accredited lab, for a dispute or a health concern | From around $120 a sample |
Notice the top row. If it’s a small surface patch, the honest answer is that you’re looking at a couple of hundred dollars, and you could probably do it yourself with a spray bottle and an afternoon. We’ll tell you that on the phone rather than send someone out.
We’re in these bathrooms every week, from the older weatherboards up the northern beaches to the brick homes through Figtree and the units near the CBD. We know what they do.
That’s why we look at the fan before we look at the ceiling.
Most single bathrooms are a one-day job. If silicone and grout have to be cut out and replaced, or the fan needs reducting, there’ll be a trade booked around it and we’ll give you the timeline up front.
| The fix | When you need it | Typical cost |
|---|---|---|
| Swap the exhaust fan | The ducting to outside is already there and the unit has just died or gone weak | $150 to $350 |
| Duct the fan to outside | The most common fix. The fan is venting into the roof and needs to discharge outdoors | $300 to $600 |
| Brand new fan installation | No fan, or no wiring. New circuit, ceiling penetration, duct run and a roof cowl or eave vent | $550 to $1,200 |
| Resilicone the shower | The silicone has gone black through and can’t be cleaned back | $500 to $900 |
| Regrout the shower | Grout is cracked, crumbling or holding mould in the joints | $650 to $1,400 |
| Reline the shower | The waterproof membrane behind the tiles has failed. Strip back, re-waterproof, retile | Several thousand |
A few things worth knowing before you get quoted.
On a regrout, labour is around three quarters of the bill, because grinding old grout out without cracking the tiles is slow work. Oddly, grout that looks worse is often cheaper to remove, since soft crumbling grout comes away easily while hard well-bonded grout that’s merely stained has to be fought for.
Watch for failed waterproofing, because it’s the one that turns a $700 job into a much bigger one. The signs: wall tiles that feel soft when you press them, water staining on the ceiling of the room below, or a leak that keeps going even after the shower’s been resealed. Regrouting the surface will not fix a membrane that’s gone.
And if the fan has been venting into your roof for fifteen years, the mould won’t have stayed in the bathroom. It’ll be on the sarking, the roof timbers and the insulation up there. That’s the honest reason a bathroom mould call can end up in the thousands, and it’s exactly why we look in the roof space before we quote.
You get the full figure, both buckets, before anything starts.
Why a Wollongong Bathroom Grows Mould Faster Than One Inland
Coastal air here carries more moisture for much of the year. That’s the backdrop to everything above. Your bathroom air starts out damper than it would an hour west, so it takes less shower steam to tip a cold surface into condensation, and everything takes longer to dry afterwards.
Now lay that over the housing stock. Plenty of Illawarra homes from the 60s through the 80s went up with a small window, a token fan, and no real thought about where the steam ended up. Add long hot showers (which I personally can’t do without during winter) with the door shut and the room never fully dries between uses.
Book Your Free Bathroom Mould Inspection
If you’re on your third round of scrubbing the same ceiling, stop scrubbing and find out why it keeps happening.
Send details in the form or call us with a description of what you’re seeing and we’ll tell you flat out whether a professional is required.
Free inspection, straight answer, no obligation. If it’s something you can sort yourself, we’ll tell you that too.
Frequently Asked Questions
Why does mould keep coming back in my bathroom?
Because the moisture never left. Cleaning removes the growth, not the conditions that grew it. The most common cause we find in older Illawarra homes is an exhaust fan discharging into the roof cavity instead of outside, so every shower sends steam above your ceiling where it condenses and comes back down. Until that moisture has somewhere to go, the mould has a reason to return.
How do I know if my exhaust fan vents outside?
Look for where it comes out. There should be a vent through an external wall, an eave, or the roof itself. If you can get into the roof space, check whether the fan has ducting attached and whether that ducting actually goes anywhere, rather than ending loose in the cavity. A fan blowing straight into the ceiling void is very common in homes built before 2022.
Can I remove bathroom mould myself?
Often, yes.
A small patch of surface mould on tile or paint wipes off and stays off. Just wear gloves and a P2 mask, ventilate the room, and you’re done. Call someone when it keeps coming back, when it’s rooted into silicone or grout, when it’s spread beyond the bathroom, or when the area is big enough that cleaning it would push spores through the house.
Does bleach kill mould in a bathroom?
Yes but with conditions.
This is one of our most frequent questions followed by “why isn’t bleach killing mould?”. On hard non-porous surfaces like tile and glass, it kills what’s sitting on top. On grout, silicone and plasterboard it doesn’t, because those are porous and the mould has roots down inside. Bleach is mostly water, so you can strip the stain while leaving the growth alive underneath. That’s why bleached silicone looks clean for a week and then darkens again.
Is bathroom mould dangerous?
It affects people differently. NSW Health links indoor mould exposure to respiratory irritation, allergic reactions and worsened asthma, and children, older people and anyone with an existing respiratory condition tend to be more sensitive.
That’s a good reason to fix a recurring problem rather than live with it. It isn’t a reason to panic about a patch you wiped off last week.
Why is the mould on the ceiling and not the walls?
The ceiling is usually the coldest surface in the room, so steam condenses there first. It’s also the surface sitting directly under the roof cavity, which matters a great deal if your fan is venting up there. Ceiling growth that keeps returning is a strong hint that the fan is the culprit.
My exhaust fan runs so why is there still mould?
Running isn’t the same as working. It might be venting into the roof, it might be underpowered, it might be clogged with dust, or it might be switching off with the light when it needs another ten minutes to clear the room. Any of those and the fan makes noise without moving the moisture out.
Whose responsibility is bathroom mould in a rental?
75% of the time it’s the owners responsibility.
Generally the owner’s, where it’s caused by a building fault such as a leak, failed waterproofing, or a fan that doesn’t vent outside. It can fall to the tenant where the room simply isn’t being ventilated. The cause decides it, which is why getting the cause identified in writing is useful. This is general information rather than legal advice, and NSW Fair Trading is the place to check your situation.
How much does it cost to remove mould from a bathroom?
A full bathroom treatment generally runs $500 to $1,000, and a small surface patch is more like $100 to $300.
The bigger variable is the cause.
Ducting a fan to vent outside is usually $300 to $600, resiliconing a shower $500 to $900, and a regrout $650 to $1,400.
If the waterproofing behind the tiles has failed, or mould has got into the roof space above, it climbs from there. The mould inspection is free, so you find out which of those you’re dealing with before you spend anything.
How long does bathroom mould removal take?
Our process is thorough so it could takea single day if it’s isolated to the ceiling and installing an exhaust fan; or if the mould has spread to nearby areas of the dwelling it could be weeks. Again, we won’t be able to tell until we do a free on-site inspection to see what we’re up against. Give us call 24/7.