The right conditions
There are many things that can cause the right conditions for mold to begin to grow in your home. To grow mold needs to have a food source, darkness, heat source, oxygen, water and very little time.
It only takes a few days of humid weather to cause mold to begin to grow in as little as 2 days! Rain fall on all kinds of surfaces including walls and fencing can lead to mold growth and of course spores which can easily be transferred to the home.
If you dry your clothing indoors using clothes horses or similar then the damp from the clothing gets into the air leading to humidity. Using a dehumidifier can reduce the chance of mold forming to keep the humidity lower than 55%.
Even the smallest leaks can cause mold to grow, which usually goes unnoticed until items are disturbed or the mold becomes so bad it is clearly visible on walls, floors or furnishings.
Floors made of concrete can become extremely cold even if carpet has been laid on top of them, the same goes for walls. When the house is warmed up again condensation can form which is an ideal breeding ground for mold.
Not having enough ventilation will make the air flow poor and even create stagnant areas. When water evaporates into steam it makes it humid and another ideal place for mold spores to grow and spread. In places where water is commonly used such as the bathroom and kitchen ventilation is extremely important.
If you have ever left your swimming costume or trunks in a bag and forgotten about it, you may have noticed mold starting to grow on the item. The same can happen if clothes are washed and perfectly cleaned but left in their wet state for just a few days, so ensure laundry is completed before going away for the weekend.
Floods can cause some of the most dangerous forms of mold, especially if the flood has been caused by outside influences such as sewerage or even the washing machine dirty water. This is because the water contains contaminants that can grow with the mold and be breathed in or accidentally ingested.
Under house water
Water can easily collect under the house, in basements and even in the houses foundations. Think about the layout of your garden and see if it slopes towards the house, if it does then you may need to rethink the landscaping to prevent water collecting around and eventually inside of the walls and house allowing mold to grow. Check regularly for holes in the structure of your home to prevent water from entering and keep an eye on guttering for cracks and blockages to keep water away from the house as much as possible.
If you have a basement check regularly to ensure that it is not damp down there and where possible keep a humidifier down there to keep the air fresh, especially if there is no ventilation by way of windows.
For more home maintenance advice, visit http://sandiego.housingcollaborative.org/maintenance/