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What Are The Common Mold Types Found In Homes And Offices?


What Are The Common Mold Types Found In Homes And Offices?

Last Updated on July 23, 2015

Many of us presume that the molds we see accumulating in our homes and offices are the same. They only differ in colour with black, green, grey, brown and even white types emerging from one damp corner to another. Whilst we often distinguish mold according to their colours, the colour does not actually tell you whether the mold is harmful or not. For that reason alone, it is best to look closer and see how the mold grows or spreads over the surface before you can conclude that it is harmful. To help you with, it will also be good to be familiar with the most common mold types that may emerge in your homes or in your place of work.

Mold types according to hazard classes


Many countries all over the world have already used the hazard class system when classifying molds into different categories. The hazard classification actually categorises a mold according to the health risks they bring.

The first category is the Hazard Class A, where the molds are classified as directly hazardous to your health. These molds commonly expose you to a higher risk of infection and likewise the creation of toxic elements. These types of molds should be removed immediately from the home or workplace right after they have been found.

Then there is the Hazard Class B mold or those molds that commonly cause allergic reactions to anyone exposed to them. Prolonged exposure to such molds will worsen your situation thus like with Hazard Class A molds, they should also be removed right away.

One last type of mold in the hazard class system is the Hazard Class C. This mold type is not known to result to any health reaction but even though that is the case, there is still reason for you to have it removed from your homes or workplaces when discovered. This is for the reason that this type can still cause structural damage.


Apart from the hazard class system, molds can also be classified in different species with some classified as dangerous and others non-harmful. For one, there is the cladosporium mold, one which belongs to either Hazard Class B or C. This common indoor mold can be black, grey, brown or green in color. This type of mold causes allergic reactions and thrives in different places from your structure’s walls to your insulation. They can also mix with dust and grow on wood.


Aspergillus, another type of indoor mold is one that can look black, white, green, yellow, brown or grey. This mold type has many other mold species and is commonly classified under Hazard Class A or B. Aspergillus basically results to infection most especially in people who are exposed to the mold and have weak immune systems. They can also create toxins in specific situations thus causing allergic reaction to some extent. They grow in the same spots where cladosporium grow but can also be found in paper products, clothing and soil.


Another common indoor mold, penicillium is that mold type that can look white, green or blue and is categorised either under Hazard Class B or C. This mold, whilst also seen in insulation, walls and in any part of a structure, can also be found in foods like fruit and cheese.


An indoor mold type that typically is grey or black in colour, Ulocladium is classified under Hazard Class B and C mold. If there is any difference this type of mold has with all other previously mentioned indoor mold types then that will be the fact that they are associated with damp places and dusty areas.


When placed under a microscope, Alternaria looks quite similar to that of Ulocladium with the grey and black colour appearing on surfaces where it thrives. Since this type of mold has been noted to cause allergic reactions, it has been classified further under the Hazard Class B mold. They thrive anywhere from soils to plants to indoor damp and dusty areas.


With either a grey or brown or white colour, Acremonium is that type of indoor mold that is often seen in drywall or sheetrock and insulation. Like Ulocladium, this mold type grows in damp areas too. What makes acremonium quite an alarming type of mold is the fact that it falls in any of the three hazard classes for molds.


If there is one characteristic that best describes this type of mold then that will be the fact that it looks black on any damp surface where it grows. Years ago, this type of mold is said to have made headlines after it has been associated with ill effects on human beings. Because of its danger, it has been classified under Hazard Class A molds. It can also create toxins that can result to more serious illnesses.

Whilst you might be familiar with the different types of indoor molds right now, we want to warn you that it will not be easy to know which type affects you just by merely looking at them. Hiring experts like us will help when it comes to mold inspection, removal and remediation.