Industrial Paint & Coatings Since 1916

Ask The Expert: The Matter of Mold, A Battle Against Decay

By Stacy Durr Albert

There’s nothing that ruins the look of beautiful wood more than unsightly stains caused by mildew or mold. Excess moisture, damp conditions and a lack of sunlight can all contribute to the fungal growth, which can lead to permanent wood damage if left untreated.


The good news is that by following a few simple guidelines, you can combat this common problem. We talked with Continental Products, Ltd., to find out what to do when mold rears its ugly head.


How can homeowners prevent mildew or mold on exterior wood?

Controlling moisture is the key. The worst mold and mildew attacks often occur where moisture levels are highest and sun/heat penetration is lowest. Airflow is also important-making sure that air is allowed to flow through otherwise inaccessible spaces such as under porches, behind walls, and under eaves and soffits so that any trapped water has a chance to dry out.


Are there any products that homeowners can apply to their wood to prevent mildew/mold from forming?

The use of a quality wood finish product will help combat many forms of decay. Continental’s WeatherSeal™ wood finish is a premium, oil-based stain, and sealant fortified with borates to help kill mold and mildew before it has a chance to take root. It’s also important to make sure all door and window joints are sealed with a high-performance sealant that helps keep water outside where it belongs.


If mold or mildew is present on wood, what should a homeowner do?

Washing works wonders-a mild detergent solution and a good scrubbing with a stiff bristle brush can make a huge difference, regardless of whether the damage is on your deck, furniture, or side of your home. A power washer can also be a good tool but should be used with caution. Overly aggressive power washing can do more harm than good to wood surfaces, so carefully check the pressure and flow settings. There are several do-it-yourself mold cleaner recipes online; most are a combination of water and bleach, or a bleach alternative like sodium per-carbonate.


What are some of the best fixes if a very large amount of mold or mildew is present on wood?

Try not to get overwhelmed. Even large amounts of mold or mildew are still manageable to clean. It may be time-consuming, but the job can usually be tackled in a single weekend with the right tools and a bit of know-how. With damage spread across a larger surface area, it’s probably best to use a pressure washer to shorten the length of the job, but even a long-handled stiff bristle brush can do the trick. Enlisting the help of some friends will also speed up the process.


Is there a certain time of year that is best to address mold/mildew repairs? Mold and mildew do not like heat or ultraviolet light, so the  best time to  tackle the remediation of mold and mildew is during warmer, sunnier months.  Doing your mold removal project during the summer also ensures that you’ll  have plenty of sunshine to dry out your wood before you apply stain. Try to plan any mold/mildew remediation projects around a two to three-day dry spell to make sure you’re not interrupted by rain showers.


How can a homeowner determine if mold/mildew issues are simply on the surface of the wood, or deeper?

If the surface of the wood has been treated with a quality stain or sealant, chances are pretty good that the mold is only on the surface. If the wood in question is in severe disrepair or has no noticeable finishing product on the surface, the mold may have penetrated more deeply into the wood structure.


There are a few simple ways to test the depth of mold penetration. One is to apply a strip of masking tape to the moldy surface, allowing it to set for about five minutes and then removing the tape. If the mold is present only on the surface, the mold will easily come up with the tape. Another method involves lightly sanding the surface with a medium-grit sandpaper. If the mold is surface only, light sanding pressure will typically remove it completely. If the mold has penetrated deeply into the wood, it may be necessary to media blast the surface to completely remove the mold prior to staining.