Persistently wet conditions, high moisture and dark and damp areas can quickly lead to yellow mould build-up. Yellow mould can have negative effects on air quality and can do structural damage to wood. To avoid these problems, identify a yellow mould infestation quickly and clean it up immediately.
Identify yellow mould. Often, yellow build-up on walls, floors or structures can be mistaken for yellow mould when it is actually something else. Visible mushrooms or thick-fruiting body growth is a telltale sign of severe yellow mould growth. However, other discolouration, such as water damage, pollen, household dust, pet urine, mineral deposits and sprayed foam insulation can often be mistaken for mould. While you can test the surface by attempting to wipe it away with a small amount of bleach, the only way to definitively determine whether a substance is mould or not is to send it to a lab.
Mix a solution of warm water and a bit of mild hand dish washing detergent in a spray bottle. You can also use a solution of 3 parts water and 1 part bleach.
Spray the area with cleaning solution and allow to stand for 10 to 15 minutes.
Scrub the area with a sponge to remove the mould.
Wipe the area clean with a wet rag and dry the surface thoroughly. Discard mouldy rags and cleaning material.
Ventilate the area and keep the relative humidity below 55% to prevent future yellow mould accumulation.
Place one or more dehumidifiers in the room to reduce the relative humidity.
Another yellow mould, known as "dog vomit slime mould" appears in gardens, particularly on mulch. This yellow mould is not harmful to plants or animals and can be temporarily removed with a hose, garden rake or shovel. Always wear protective goggles, gloves and a mask when dealing with mould. Testing possible mould samples can be costly. For smaller jobs, it suffices to simply clean it up without testing. According to the Center for Disease Control, mould can exacerbate asthma and allergies and cause hay fever-like symptoms. Severe yellow mould infestation can weaken wood. You may wish to simply replace a wooden support or structure.