By Networx

The last thing that you want to deal with when buying, selling or living in a house is mold, especially in the visible areas like the bathroom. 


As a green contractor, our clients expect us to build in such a way so mold never appears, however some houses already have a mold problem before we even start the project.

Not only are our clients concerned about mold, members on home improvement forums such as have the same question:  “How do I kill the mold in my bathroom?” 


Unfortunately, the “knee jerk” response that most people offer as a suggestion is to try to kill the mold with bleach.  This common perception of dealing with mold can cause it to spread and also does not deal with the cause of the problem.


What is mold and why is mold growing on the walls and other surfaces of the bathroom in the first place?  Mold is a fungus and is nature’s way of breaking organic matter down so new like can emerge.

Mold grows on the surfaces of the bathroom only if you have several conditions occurring at the same time.  Let’s explore the causes of mold growth, then discuss some of the solutions for dealing with current mold growth and ways to prevent mold from growing in the first place.


Mold likes to eat

The first thing you need is a food source and most bathrooms have many potential food sources for mold.  In showers and bathtub surrounds, you might see mold and/or mildew growing in the grout lines or in the corners where the moisture builds up.   The mold is not eating the grout itself; it is eating deposits of organic material that is coming off of us when we shower.  When you rinse, the water splashes on the walls and the grout collects some of the dirt and organic materials that you have just washed off your body.


Mold also likes to eat the materials that are used to construct the bathroom.  Most wall coverings in the US are now some sort of drywall.  The newest building codes require that they come with asphalt in the outer layer which would inhibit mold growth, however if you have an older home or your contractor installed the wrong type you could have an ongoing mold problem.  


The outer layer of typical drywall is usually some sort of paper material.  This paper is an excellent food source for mold and when introduced to a moist climate such as a bathroom, it can start to mold.  We have seen houses where they accidentally installed the incorrect type of sheetrock near the shower and it starts to mold within a few months of exposure to the steam from the shower.


Solution:  Starve the mold

Clean your tile more often so the mold does not have a chance to start eating the residue.  Prevention allows you to avoid harmful chemicals that are necessary to kill the mold.  If you only clean the shower once a year, you will have to wear safety goggle and a respirator and a harsh chemical.  However, if you use a safe cleaner approved by organizations like GreenSeal  and clean more frequently, you will be able to prevent mold and avoid harmful chemicals that can pollute your indoor air.


When constructing the bathroom, you should also use products that are mold resistant (also known as "inorganic").  One of the products that our company uses on both basements and bathrooms is a type of drywall called “paperless” drywall.  Instead of using paper to hold together the drywall, materials such as fiberglass are used instead.  Georgia Pacific started promoting their DensArmor plus line several years ago as an excellent alternative to standard drywall in damp locations such as bathrooms, basements and garages.  By using this product, we can sleep at night knowing that our clients are not going to have a mold problem that can potential make them sick and open us up to liability lawsuits.


Mold likes moisture

Like us, mold cannot live on food alone; it also needs a water source.  When you take a shower or a hot bath the steam collects on the tile, on the walls and also on the ceiling.  The tiles start to grow mold because of the organic residue and the moisture.   You could have a dirty shower and no moisture and the mold would not grow.