Combatting paint odours

June 12th, 2020

When it comes to decorating, one consideration with using paint can be the smell it produces.

Whether you are working in a public area, such as a school or hospital, where you need to consider the sensitivities of others, or in an enclosed space at home, it can be important to keep odours to a minimum.

To tackle the issue, you must first go to the source. 

There are usually two potential causes of paint-related odours: one is predictable while the other is not.

Predictable: Solvents

We are all familiar with the smell of fresh paint. Unfortunately, though, the smell of solvent-based paints can be quite noticeable. And this is sometimes enough to outweigh the benefits of using a solvent-based product: the attractive gloss finish and good ‘levelling’ (i.e. brush strokes fill themselves in to create a smooth surface).

In this instance, the odour is caused by the evaporation of solvents that are mixed in with the paint to thin it. This ‘gassing off’ is referred to as a paint’s VOC level (Volatile Organic Compound), which is relatively high for solvent-based mediums.

The solution is simple: switch to water-based paint. With recent advances in technology, the drawbacks of using water-based paint are few and far between. And the benefits include easy cleanup with water and—most importantly for odours—low VOCs. There are significantly less of those nasty-smelling solvents.

One particular product that gives you the best of both worlds is Mythic. This non-toxic paint offers the same durability and coverage that you would expect from premium paint, but without the offensive smell. It is ideal for delicate noses.

If, however, the use of solvent-based paint is unavoidable, please note that good ventilation is very important—not just to fight those odours, but for health reasons too.

Unpredictable: ‘Wall odour phenomenon’

In some very rare instances, once the paint is dry, you can be left with an unusual smell that is unlike the normal smell of paint. And it can be accentuated by the warmth of direct sunlight or by draughts disturbing the air.

Research has shown that this happens in areas that are prone to bacterial growth because the odour is caused by microbes that pre-exist on the wall surface. And the reason this is such a difficult problem to predict is that those microbes are invisible to the naked eye.

The smell comes as a combined result of the fresh paint not only reacting with the bacteria but also sealing it in behind the new coat and the microbes continue to give off an unpleasant whiff from beneath that new coat.

This problem is not brand-specific; it has been known to happen with a wide range of paints. And while the likelihood of experiencing the ‘wall odour phenomenon’ is about 1 in 100,000, there have been a growing number of reports. This is most likely due to the lower solvent content of paints in general, as companies now face pressure to reduce their VOC levels. Hence, they no longer contain the active ingredients that would conceal those smells.

So, while there are no associated health and safety risks, the problem begs a solution. You will be glad to know there are a few things you can do to combat ‘wall odour phenomenon’. For starters, we advise that you wash down walls prior to painting them. Neglecting to do so has meant that this problem is common among homeowners who move into a property whose previous occupants have not kept their walls clean.

After that, you can use a solvent-based primer to create an odour proof seal. Or, better yet, ensure that any remaining bacteria are eliminated by utilising paints that contain anti-bacterial elements. In this instance, we recommend that you use an alkali resistant sealer. Application is incredibly simple, and your normal paint can be applied straight over the top

However, alkali resistant sealers can be a little tricky to come by because this is not a common problem. So please contact your local Brewers to ask about availability and we will be able to help.