Mould and dampness


Love the new forum!:)

Tenants are moving out of ex NSW commission house, fibro and iron. It has always had mould problems and i want to fix them this time once and for all.
Mould is on the cornices in bedrooms and in the lounge room.

It is in a very cold climate - consistently -6 to - 10 overnight for a few weeks in July so lots of condensation. Appears to have sufficient underfloor ventilation - maybe not enough - how do I tell?

Any suggestions on what to do?


1. Insulate the roof space
2. If heating with gas advise tennants to ventilate a little during heating. The combustion process produces mainly water vapour, and when it hits COLD gyprock it condenses feeding those love;y mould spores.
3. 5 % chlorine bleach, apply with roller or brush but be careful not to get onto carpet or other materials before painting
4. Before painting theres an anti mould additive for the paint cant remember its name
5. Use a good quality ceiling paint that can take a bit of washing because then you can just do the bleach thing every couple of years.

No responisbility taken :O)


The anti-mould additive to paint and grout that I have used is called 'VC175 Mould Killer", they also do an anti-mould treatment for use prior to painting. Contact tthe Flood Company on 1800 226 113 for stockists.
G'day Cathy et al

By 'flued' oil fired heating, do you mean (a) the heater is in one spot flued to outside, or (b) that it warms air which is then recirculated throughout the house, as ducted heating with a return air vent?

If (a), then ventilation, that is, circulation of air, is the problem. The warm, moist (people cook, wash & breathe) air rises to the ceiling, condenses as Rolf mentioned, then has nowhere to go.

Consider installing ceiling fans if the budget doesn't extend to ducted heating. The fans themselves can be bought from KMart for less than $50 each, plus electrician's fee, and can be fitted as close to the ceiling as possible. They don't have to be set to push the air down , as this can cause uncomfortable draughts, but will circulate the air within the room, balancing out the room temperature, and reducing heating bills. And if left switched on permanently on the lowest setting, will certainly dry out the plasterboards and keep the room fresh.

As a side benefit, if the fan is set to blow down, place the clothes horse / drying frame underneath, and the washing will get dry in an amazingly short time!!


Thanks Kristine

The heater is one unit in one position flued to outside. The house has ceiling fans in one bedroom and the lounge. But I have never talked to the tenants about using them in winter. So perhaps this could be some way to solving the problem ..... maybe that's why the Dept of Housing installed them.

Thanks for that


This is a 'cut & paste' from 'Our House', a TV article on Mould Solutions.

The gadget solutions seem a great idea, however, providing one means you are responsible for its safety & maintenance etc.

My vote would be the fans. - Just as a matter of interest, have you ever 'taken the temperature' of a room at different heights? I rented a small house for a time, and no matter the efforts of the wall furnace, I was forever 'walking' through hot and cold spots throughout the house.

I was amazed to find that the air at floor level was ten degrees !!! colder than the air just under the ceiling. And with no ceiling fan, there was no way of circulating that expensive heat back to where I was sitting with a blanket over my knees.
Should your tenants decide to turn the fans on, they may notice a significant improvement in comfort, with noticeably lower heating costs for the remainder of the winter. And no more mould!!

Good luck


Damp clothes, rotting floorboards and curling photographs are all signs of mould and mildew in the house. It is a common problem with some very simple solutions. Just choose the mould-buster that best suits your home.

Wardrobes, walls, ceilings, curtains and furniture are the most common victims of mould and mildew. It can also cause condensation on windows and ruin books, papers and clothing. Not only is mould an eyesore, but it can also be unhealthy, particularly for allergy and asthma sufferers.

Combined with natural humidity, the steam and moisture created by cooking, showering, bathing and washing can result in mould. It is particularly common in tropical and sub-tropical parts of Australia where the air is damp and hot.

There are two common ways for stopping mould — above or below the floor. Sub floor ventilation includes wind powered turbos, electrical fans and vents. Above the floor preventative treatments include dehumidifiers and wardrobe heaters.

Start by having the sub floor ventilation in your home checked. Many houses suffer from inadequate ventilation due to poor sub floor venting, but aren't aware they have a problem. Make sure you get professional advice — too much sub floor ventilation can be just as bad as too little.

Mould often grows under houses with inadequate ventilation. You can prevent mould by installing extra vents (passive vents) or force fan ventilation (wind turbo).

Wind powered turbo ventilation systems can be installed in situations where it is not practical to install Anti-Damp vents, such as areas with high soil levels or homes with little access (semis or terrace houses). They are mounted on a 100mm or 150mm pipe and often used in conjunction with Anti-Damp vents. Fans are also available, however they have a limited life span.

Anti-Damp vents help remove musty smells, mould, fungi and rotting floorboards in the sub-floor area.

The advantages of good sub floor ventilation:
Prevents fungi, mould, rotting boards, musty smells, bowing timber and lifting lino or vinyl tiles.
Discourages termites by creating an airy, light environment.
Eight times the air flow of standard terracotta vents.
Promotes a healthy living environment for people with respiratory conditions.
No running costs and minimal maintenance required.


Wardrobe Heaters:
Wardrobe heaters fight persistent mould and mildew in the closet. We looked at Dampp-Chaser Closet DeHumidifiers that warm, dry and circulate wardrobe air, effectively stopping mildew, mould, musty odours and rust. As an added bonus, they are simple to operate — just set them and forget them.

Dampp-Chaser Closet DeHumidifiers are mounted on the baseboard (or the wall above the baseboard) with brackets and plug into the nearest power point. Don't use staples on the electrical cord and make sure you keep the heater horizontal. The DeHumidifier circulates the air in the closet 150 times a day and can be left on during most seasons (it uses very little energy).

Dry home DeHumidifiers quietly remove large amounts of water from the air. They are portable and can be easily rolled from room to room. When the DeHumidifier's four litre water container is full, it will automatically shut down.

DeHumidifiers have non-corroding parts, fan motors, adjustable dryness control and a two year guarantee. There are three Dry Home models to choose from, all with varied powers.

Above Floor Treatments:
Dry Home sell a range of dehumidifiers, air purifiers and wardrobe heaters. Wardrobe heaters cost between $70 and $100 (plus delivery). Dehumidifiers cost between $700 and $1000.