Don’t just paint it! Five steps for killing mold safely and impressing clients

Unless you only ever paint new surfaces, you’ll certainly come across moldy indoor conditions sometimes as you work. But it’s how you deal with mold that says a lot about the quality of your skills as a painter and the way clients perceive you as a professional. That’s why mold control skills are something you should take seriously. It’s really a diligence issue. The laziest option out there is to just push the roller over mold and forget about it, but that’s wasted opportunity  on two counts. Besides the fact that live mold will almost certainly come back soon, you’ve missed an opportunity to gain repeat business through word of mouth.


Most people are scared of mold because it can present a health hazard. And while not all mold is harmful, it’s not practical to figure out whether or not a particular growth is the so-called “toxic mold” Stachybotrys Chartarum. That’s why dealing with all mold effectively and in an ecologically sound way is not only the best approach, it’ll make you look like a hero, too. So let your clients know that you’re applying the following simple but effective five step mold control process to their project and it could lead to your next jobs.


1. Assess the situation

While the mold you find as you size up jobs is probably no secret to your clients, full disclosure with them of what you find is still the best policy. It lets clients know that you’re on the ball and it gives you a chance to explain how you’ll be dealing with their mold issue and why it’s important. From a practical point of view, the main thing is to figure out how big and bad the mold growth is. If it’s the usual sort of black or grey mold you sometimes find on walls, ceilings and floors, then you can safely use the  techniques you’ll learn about here. If the mold is associated with a sewage leak, or if it covers an area larger than a few sheets of plywood, then recommend that your client call a mold abatement professional.


2. Get rid of the moisture

Mold always grows in the presence of moisture, so full mold control always begins by
making an area drier than it was. Liquid water leaks are easy enough to spot, but the majority of indoor mold is caused by chronically high humidity conditions. Under-ventilated bathrooms are an extremely common example, but so is higher-than-ideal wintertime indoor humidity levels. Inadequately sealed or insulated walls and ceilings are also a common cause of condensation and mold growth. Fixing these  underlying causes is more than you can do as a painter, but it’s important to recognize and point them out to your clients anyway. While the mold-killing techniques you’ll learn about here do offer some residual mold control effects,  there’s no substitute for reliably dry conditions year-round. Whatever you do, don’t rush ahead and prematurely begin mold-prep steps just because it suits your painting schedule. Instead, use heat and fans to dry any damp and moldy situations before tackling the next step.


3. Kill the mold

For years bleach and water solutions have been the go-to option for killing mold on
surfaces, but there are two reasons it’s not the best idea. One of these is indoor air quality. How much sense does it make to use low VOC coatings and green painting techniques if you’re going to turn around and fumigate a client’s house with sodium hypochlorite fumes from bleach? Besides, bleach isn’t even all that effective at killing mold on the kind of porous surfaces you often run into as a painter. Lab analysis done at Oregon State University concludes that “while bleach is often recommended for remediation of surface mold on wood, our results illustrate that the treatment does not eliminate the surface microflora.” Bleach doesn’t always have the ability to penetrate deeply enough into porous surfaces to kill all hidden mold roots reliably. This explains why improperly killed mold often comes back quicker than it took to start growing in the first place.

All this is why it makes sense to use a registered, non-toxic, bleach-free fungicide for killing mold on surfaces before painting. The most widely available product I’ve tested is Concrobium Mold Control (; 866.811.4148). It’s an odourless liquid that you spray or fog onto surfaces, and it’s the same stuff used by many mold abatement professionals. Mold and mold spores are killed by mechanical crushing action as the liquid dries, not by any toxic effect. That’s why this product is harmless to everything except mold. Explain all this to your clients and you’ll let them know how much you take their safety seriously. Besides being just the decent thing to do, real care is also the best PR.


4. Discourage mold regrowth

something that kills mold and fungus, is a substance that discourages mold regrowth. Concrobium Mold Control is a proven fungistat as well as a fungicide, but you still need to recommend ways your clients can reduce the moisture conditions that led to mold growth in the first place. It’s good for their health and home, and you’ll look better because your paint jobs will last longer. See Mold Problems, Mold Solutions on page TK for details.

5. Eliminate mold staining

Dead mold still looks dark and ugly, and while this is not always a problem when new paint is going down anyway, sometimes paint covers better when the stains are gone  first. The most effective option I’ve found so far for removing mold staining is an oxygen-based product call Mold Stain Eraser. It comes as a white powder that you mix with warm water and let sit for 10 or 15 minutes. Apply the solution to moldstained
surfaces and it usually turns black and grey areas clean without any scrubbing.

Sometimes a little scrubbing is necessary, but not usually. This same product also removes grey, weathered stains on exterior wood while still preserving natural wood grain patterns. It’s an effective way to brighten exterior wood before refinishing.
Painting is like any trade. Diligence, know how and attention to detail marks the difference between bad work and great work. And while you won’t have to deal with mold on every job, it’s good to be able to handle the challenge with confidence when it does come up.

[textblock style=”3″]MOLD PROBLEMS, MOLD SOLUTIONS
Here are four typical indoor mold situations and recommendations you can offer clients for combating them:

Mold growth on inside faces of exterior walls:
Commonly caused by inadequate insulation that allows interior wall surfaces to become cold enough in winter to cause condensation. Increase ventilation by moving beds, dressers and desks further away from walls, use fans to move air and lower indoor humidity levels with a heat recovery ventilator.

Moldy bathroom:
Ventilation fans in most bathrooms are under-sized and under-used, leading to chronically high humidity levels. Encourage clients to run bathroom exhaust fans for 20 minutes after each shower and to replace existing fan with higher capacity model. Aim for a fan that moves 10x to 12x the air volume of the bathroom each hour.

Mold on window frames:
This is also caused by indoor wintertime humidity levels that are too high, so an HRV can definitely help. Most homes need a relative humidity level lower than 40% to  prevent running window condensation when outdoor temperatures are lower than -15ºC. Even still, clients should keep curtains open as much as possible during cold weather, especially at night. Lack of ventilation in front of windows during cold  naps will  cause running window condensation to develop even when indoor humidity levels are  otherwise low enough.

Moldy attic access hatch:
Most attic hatches are simply un-insulated pieces of drywall, and this means they get cold enough in winter to form condensation. Glue a 2”-thick layer of foam to the top of  the hatch to keep it warm and condensation-free.Your text[/textblock]

Sharing is caring!