If you are undertaking a DIY home renovation project and notice a strong stink of rotten eggs coming from your wall plaster, you are probably wondering if there is something wrong. Believe it or not, this is perfectly normal. But,

Why Does Wall Plaster Smell Of Rotten Eggs?

If your wall plaster smells of rotten eggs, the most likely culprit is hydrogen sulfide gas. The presence of sulfide molecules in hardwall plaster is more common than many people realize, and it can be caused by a number of different reasons.

I’m going to briefly touch upon the potential sources of hydrogen sulfide gas in your wall plaster, and some easy but effective methods of addressing it.

What is Hydrogen Sulfide Gas?

Before we get into the details of why and how your wall plaster ends up smelling like rotten eggs, let’s start by answering what hydrogen sulfide gas is in the first place.

Hydrogen sulfide gas is a chemical compound that is made up of 2 hydrogen atoms and 1 sulfur atom. Known for its H2S formula, hydrogen sulfide gas is the resulting byproduct of the bacterial breakdown of organic matter.

In other words, under normal circumstances, the presence of the gas’s rotten egg smell is a sign of bacteria.

Contaminated water mixed in with wallplaster

Should You Worry About Hydrogen Sulfide Gas?

Hydrogen sulfide gas is toxic and can be harmful to humans if inhaled directly and in high concentrations.

If you ever smell hydrogen sulfide remember that it can irritate the eyes and respiratory tract. As the concentration gets higher and higher you may start to experience dizziness, headaches, and eventually loss of consciousness and death.

However, at low concentrations, such as those likely to cause a smell of rotten eggs in wall plaster, it should not pose any serious threat to your health.

Reasons Why Your Wall Plaster Might Have Hydrogen Sulfide Gas

Surprisingly there are several reasons why hydrogen sulfide gas could develop in your wall plaster. The first, and most common cause is the use of contaminated water when mixing the plaster.

If the water you use to mix your plaster contains bacteria, these tiny microorganisms will continue to reproduce inside the plaster mix and release hydrogen sulfide gas.

The second most common cause of hydrogen sulfide levels in your hard wall plaster is the use of sulfuric materials, such as gypsum, etc.

Gypsum, a sulfide mineral, is one extremely popular ingredient in wall plaster, and it has the capacity of releasing residual levels of hydrogen sulfide gas. This process is accelerated by the presence of moisture, which means it’s likely to happen when mixing wall plaster.

Additionally, the following factors can also contribute to the production of hydrogen sulfide gas in wall plaster, resulting in a distinct rotten eggs smell.

  • Poor Ventilation: If the work area where you apply your wall plaster is not ventilated well, an environment conducive to bacterial growth can develop. Once this happens, the probability of hydrogen sulfide gas appearing increases exponentially.
  • High Humidity: High humidity levels in the area where the plaster was applied will also contribute to the presence of microscopic organisms. If you smell rotten eggs in your wall plaster, look out for wet sources of high humidity, such as a leaky roof or bad plumbing.
Removing Rotten Egg Smell from Your Wall Plaster

How Do You Deal With Rotten Egg Smell In Your Wall Plaster?

Since the presence of a rotten egg smell in your wall plaster can represent a health hazard, albeit a minor one under normal circumstances, it is important to address it as soon as possible. Moreover, hydrogen sulfide gas can weaken the structural integrity of your project.

The simplest way to resolve the problem is to completely remove any plaster with the offensive rotten egg smell, and replace it with a fresh batch of plaster.

If you catch a whiff of rotten eggs as you mix your plaster, dispose of it right away. Additionally, think about ways to address the root problem, such as identifying the source of contaminated water, the reason for poor ventilation, etc.

Remember that freshly mixed and applied wall plaster should not have a particularly strong smell, and it should not smell like rotten eggs. The presence of such a smell should be taken as a sign that something is amiss.