Bathroom easily develops mildew / fungus spots

sunhux used Ask the Experts™
My bathroom tends to develop dark patches/spots of mildews/fungus
on the edges, toothbrushes, towels (that are hang in the bathroom),
shampoo caps,  practically anywhere in the bathroom.

I've thought of mopping the room dry but it's frequently used so this
is not practical.

These dark patches can't be scrubbed off & will need fungus gels to
be applied (& after a few hours, they can be removed).  They can
form in a matter of a day or two on towels.

Would a ventilator help?

Is there any chemical or how can I identify the source of the issue?
My old house's bathroom didn't have this issue.

What  else can I do to minimize these fungal formations?
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JohnBusiness Consultant (Owner)
Most Valuable Expert 2012
Expert of the Year 2018
1. Get an anti fungal solution (Hardware Store) and clean thoroughly and wipe with the anti fungal solution. Buy new toothbrushes and personal stuff like that.

2. Clean the walls and floor and tub/toilet and wipe with anti fungal solution

3. Put in a small de-humidifier in the room to keep it dry.
Stacy RichardDirector of Member Experience  
Bleach works to kill the fungus.   Make sure you wear a mask so that you are not inhaling when you clean.

Make sure you have a ventilation  fan and leave it on 30 minutes after you shower

Use a mildew-resistant shower curtain and wash or replace frequently.  

Do not keep the shampoos shower gels or loofahs in the shower as they can provide places for the mold to grow.


After the warm shower in the old house, the 'steam' just escapes through the windows
while in this new place, the windows is always closed.  Yes, bleach works, just don't want
to get to the skin accidentally or the skin will 'crumple & ..."
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JohnBusiness Consultant (Owner)
Most Valuable Expert 2012
Expert of the Year 2018

You need to ventilate your house.  We keep a window open a crack in our bathroom to improve ventilation.
Stacy RichardDirector of Member Experience  
Agree with John ventilation is a must.   Also, you want to always wear gloves this will protect your skin.

Also can use a daily shower spray like Method this will reduce mildew
The mildew and mould form because of the persistent moisture in the bathroom. Remove the moisture and you'll remove the problem.

is there any reason why the bathroom window is always closed? Does it have a summer setting, which allows it to be locked in a slightly open position? If there are reasons for keeping the window permanently closed (easy access by petty criminals, strong smells from adjacent properties, etc.) then fitting a substantial extractor that runs for at least fifteen minutes after the bathroom is vacated will go some way towards alleviating the problem and will also reduce expenditure on chemicals and treatments for dealing with the mildew that does appear.


> is there any reason why the bathroom window is always closed?
The air that comes in from that window is very dusty: guess will
need a ventilator that pushes air out (ie air doesn't come in but
goes out.  This is the bathroom that's inside the master  bedroom.
I keep the its door closed almost all the time as don't want to warm
& humid air to get into the master bedroom (& caused moulds to
form in the bedroom as well).

Come to think of it, the common bathroom doesn't have this
issue as it's door is open most of the time when not in use as
it leads to the big living room with plenty of air movement
(the only window of the common bathroom is always open
 too as the air that comes from the outside is on the same
 side as the master bathroom & the air is dusty too)


(the only window of the common bathroom is always open
  should read
(the only window of the common bathroom is always closed
An extractor fan is designed to push air from the inside of a room to somewhere outside that room; in your case that somewhere is literally outside! Such fans are also commonly described as ventilator fans, so the terms can be interchangeable.

Have you considered installing an allergen screen on the window in question? These are intended for people who suffer from breathing problems and so are specifically designed to filter out dust particles, pollen, and other irritants while allowing air flow and air movement. Here's a link to a UK website offering this type of product:

As Singapore is very densely populated and urbanised I don't doubt that similar products are available there, but the link just illustrates a possible alternative solution to the problem.
I agree with what Perarduaadastra has been saying.  You need to install an extractor fan.  In the UK an extractor fan is compulsory in all bathrooms in new houses and if you are adding a bathroom or en-suite (in the bedroom) shower enclosure or room to any house the building regulations require you to have an extractor fan.

Extractor fans come in different types and formats.  Some are wall mounted and require a hole to be bored through the wall for the vent duct. There are also ceiling mounted fans where you need to cut a hole up into the ceiling and then have a duct that goes to the outside of the house somewhere.  This could be up through the roof or through a hole in the wall or out through the eaves (for example a hole in the soffit board).  A ceiling fan can be a surface mounted unit or the actual electric motor can be hidden up inside the ceiling void and all you see is the flush mounted grillecovering the hole in the ceiling.

Where the duct emerges to the outside of the house you will usually have a square plate with flaps that stay in the closed position by gravity and open as air is being blown through - a non-return "shutter".  Extractor fans that use ducting can have this non-return shutter installed in-line as part of the duct.  Wall mounted extractor fans usually use an electrically controlled non-return shutter that opens when the fan is turned on.

There are various things that you need to know about when installing an extractor fan.  Firstly you have axial and centrifugal.  An axial fan just sucks air straight through the fan (impeller) and is the type usually found for small domestic bathrooms where the vent goes straight through the wall.  They usually use 4 inch ducts or occasionally 6 inch ones for the more powerful versions.  A centrifugal fan pulls the air in and deflects it sideways into a chamber leading to the duct.  This allows it to build up more pressure than an axial fan to force air through a longer ducting pipe in cases where it is not possible to bore a hole right through the wall where the fan unit is mounted on the inside wall.  If the duct has to be quite long you usually need a centrifugal fan or a more powerful axial or centrifugal fan that is mounted inside the ceiling void.  Domestic centrifugal extractor fans are usually more expensive than axial ones.

Domestic axial extractor fans can be either mains (230/240 volts) or low voltage (12 volts) and are usually available with different switching options such as a manual pull cord, a timer switch that allows it to run on, a humidistat that senses moisture and automatically turns on, and sometimes even a PIR sensor that detects somebody in the room or cubicle and turns on.  They can usually be wired to turn on when the light in the bath/shower room is turned on, and if you have an electric shower with a pull switch you could have this switch the fan on and off.

The large extractor fans that you mount in the ceiling void are usually mains powered and are not pretty because they are not seen.  They are usually quite large and have black plastic casings.  I have one of these (a Manrose) inline units up in my loft/attic above the bathroom.  The duct is connected at the intake side to a simple flush-mounted ceiling grille above the bath which has a wall-mounted electric shower, and the output duct goes across the ceiling above the bedroom to a flush-mount grille fitted to my soffit board under the eaves of the roof.  There is an in-line circular non-return flap that works by gravity to close off the duct when no air is being pushed through it.   I installed this kind because I did not want to bore a hole through the outside wall of my bathroom and because it gets cold and windy here in Scotland and it is not practical to leave the bathroom window slightly open while showering.  I needed the powerful fan type vecause of the length of flexi-pipe duct.  The unit produces more noise and vibration than the shiny white plastic ones that mount on the inside wall of bathrooms, so I mounted it on rubber washers to reduce the noise.

Noise is an important consideration.  Most extractor fans will show the db level and those that are designed to be quiet often use the word like silent or whisper in their model names.

Ducts come in different types.  You can use round flexi-hose (wire coil covered with plastic that stretches out and bends) similar to the type used to duct moist air from a tumble dryer.  There is also rigid round or rectangular ducting with various adapter joints to accommodate bends and corners and allows you to connect rectangular ducting to a fan that has a round duct on it and vice versa.  The outside wall grilles and non-return flaps come in different shapes and sizes.  Some are brown and are the size of a standard building brick to make them less obvious.

The most important aspect you would need to know is the extraction rate.  This is usually measured in cubic metres per hour or litres per second.  UK Building refulations actually specify the minimum extraction rate for bathrooms, but any decent online retailer or knowledgeable DIY advisor would be able to tell you what fans would be best suited to an en-suite shower room or cubicle.  A cheap four inch axial fan will extract 70m3/hour or less, but the better 4 inch versions will extract around 95m3/hour or more.  Any extractor fan that is mounted on an inside wall or where the motor is part of the ceiling mounted unit should be rated as being IP45 or IP46 ( so that it is protected against spraying water and can be mounted anywhere in a bathroom or shower enclosure.  An inline extractor motor that is mounted in a ceiling void and water cannot spray into the motor from the bathroom doesn't have to have the same "water ingress rating".

The lower powered wall mounted extractor fans can normally be connected to an existing lighting circuit and you would install a fused isolation switch somewhere away from potential water splashes and insert the correct fuse to match that needed by the fan.  This is something that I would not recommend as a do-it-yourself job unless you have experience with connecting domestic electrical appliances to mains cabling and you know whether this is a job that does not require a certified electrician by law.

I thought it would be easy to find standard bathroom extractor fans by looking at DIY stores in Singapore, but all I am seeing is "ventilation" fans for circulating air and cooling, and not "extractor" fans.  Popular brand names here are Vent-Axia, Xpelair and Manrose.  These may be international names, but perhaps not.  You might be able to get what you need on Amazon, but I have a feeling that shipping could be expensive.  I think that if you decide to get an extractor fan installed you will need to contact an electrician who has experience in this field and get a quote.

Other options would be using a glass cutter to cut a round hole in your bedroom window and installing a "ventilation" fan, then just leave the door to your shower room open.

Another option would be an electical dehumidifier that extracts moisture from the air in your bedroom and drips it into a container that you empty when full.  That doesn't solve the problem with mildew inside your shower room or cubicle.  You would have to leave the door open to the bedroom.  If the silicone sealant around tiles and shower tray have black mould growing inside the sealant, then you need to peel it out and reseal with mould resistant silicone sealand. Mould can also grow on the grout between ceramic wall tiles.  This can be scrubbed out with mould killing compound and you can buy solutions to waterproof the grout.  I don't recommend using the aerosol grout waterproofer in an unventilated room though.


Certainly, I've considerred an extractor fan which I've installed in the
kitchen which is extremely warm with only a very small windows of
2ft x 6in  (that slides open) when the gas stoves are on & I don't want
the cooking fumes to spill into living room: as the air outside the
kitchen can be dusty, I blocked 1 ft of the kitchen window with the
sliding window & DIYed (using sticky tapes) 2 x 6" square extractor
fans: it certainly reduce the heat & fumes in the kitchen.

Thing about the master bathroom is the window is not the sliding
type but "open out" of 3 ft x 2ft : I can't think of how to DIY other
than getting a contractor to take away the window panel & put in
a large extractor: this bathroom window also open out to an open
& dangerous heights (yes, I live in high-rise), unlike the kitchen
which opens out to a balcony that has metal grills that prevent
kids from falling out of the balcony: yes, I have an intellectually-
disabled teen boy & a self-harming teen girl so currently that
windows panel is locked to prevent any untoward incident.

Currently not prepared to invest in a costly renovation for that
master bathroom window.
In view of the particular difficulties of your situation then perhaps the allergen screen approach might be the best fit. It shouldn't be too difficult to devise a method of firmly fixing the window in a set position with a gap wide enough to allow adequate air movement but small enough to prevent even a determined teenager from fitting into or through it. As you live in a high-rise the risk of unwelcome intruders is negligible so security isn't an issue, and the screen itself would prevent the ingress of rain when the weather was inclement.
Thank you sunhux

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