How can I effectively remove black mold from my picnic table before restaining it?
Asked by Jacqueline Ford 
2 months ago
Last Updated: July 31, 2024
What’s the best way to get rid of this black ‘mold’ on my picnic table? I’ve tried sanding it down multiple times but I really want to restain it. Just need to figure out how to get rid of the black gunk first. Appreciate any advice!
Mix 1/2 cup of vinegar per gallon of water. Use a sponge to apply it, leave it for 15-20 minutes, and then pressure wash to clean
You must not have sanded it too many times if you can still see the previous finish. Maybe try hitting it with a 40 grit belt on a belt sander next time. Just make sure you hold on tight.
I totally get where you’re coming from. I personally used an orbital sander with 60 grit and went over the area multiple times. The thought of replacing the wood crossed my mind, but I wasn’t too keen on spending $50 on that.
It seems like you might have to take off more material than you initially thought, the damage appears to be quite deep. Have you looked into using wood bleach? Although, considering the cost and time involved, you might be better off just replacing the boards.
Make sure to sand down to the bare wood. If you don’t remove enough of the top layer, spray with mold killer and let it dry. I’d recommend spraying 24 hours before sanding as well
Mix bleach with water
Just a heads up, bleach doesn’t eliminate mold on porous surfaces
Well, it’s always done the trick for me. 🤷
You know, I wasn’t stating my opinion or experience. Bleach simply removes the appearance of mold on porous surfaces.
https://www.healthline.com/health/does-bleach-kill-mold
It may not completely resolve the issue. However, it can eliminate mold on the surface temporarily until you can address the root cause
Vinegar has the ability to seep into surfaces that are porous
There’s a deck cleaner called Mold Armor that works really well. I actually got a gallon on clearance at lowes for only $3
Try using a deck wash that includes mold and fungus remover, follow the instructions on the container, and use a stiff nylon scrub brush. Instead of a pressure washer, consider using a garden hose with a stream head sprayer to avoid damaging the wood. Allow the boards to dry for a few days, ideally a week, before sanding the surfaces smooth and removing any remaining old paint or stain. After that, you can repaint or restain the table. Best of luck!
So I work on refinishing decks and fences, and I have to say this is quite accurate. If it’s a sunny day, you might want to wait for about 24 to 48 hours. If not, just ensure the boards are completely dry before you put on the stain.
Thanks for confirming, ! 👍 I’ve learned through trial and error and fixing others’ mistakes. Pressure washers can be risky in inexperienced hands. But traditional washing and scrubbing are usually safer. I’m sure, being in the business, you’ve seen people cause damage by being too aggressive with cleaning.
And I see eye to eye on this. I prefer using an electric pressure washer with a lower psi rating and sticking to the 40° tip at a consistent distance to avoid damaging the wood fibers. It may not ruin the wood, but it definitely calls for some sanding afterward. I follow up with a stiff bristle deck brush after applying the solution, keeping the surface moist while it does its job. Then it’s rinse off, rinse off again, and rinse off one more time.
When wood is subjected to high pressure, it can cause the softer cellulose to be blasted out of the wood structure, leaving behind just the lattice structure. This can lead to trapping water and dirt, resulting in more rot, mildew, and fungus. I’ve witnessed decks that were pressure washed incorrectly failing within a couple of years due to this issue. That’s why I prefer using an electric pressure washer with a fan tip to avoid damaging the wood. I would caution against using a pressure washer to clean wood, especially for those who are new to it.
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If you have black mold on your basement walls, they say using a solution of vinegar and borax is the way to go. I read that bleach might not always do the trick in killing black mold, but it can at least change the color of the spores.
I heard that mixing liquid pool chlorine half and half with water works well.
You could power wash it and then apply deck stain to finish.
How was it sanded? I mean, did you use a belt sander with coarse grit to take off 1/8″ in no time?
Check out Lowe’s or Home Depot. Look for a fungicide specifically for MOLD.
Avoid using bleach. If you do, the mold will return even with the sealant.
Put a sealant on top. It looks good.
Just paint or stain it, and the issue will be barely noticeable.
I appreciate all the helpful responses. I think I’ll give vinegar a shot and maybe consider using a pressure washer.
A few days of direct sunlight will do the trick in killing it.
Can you believe it gets direct sunlight every single day? I never expected that kind of exposure to the sun.
I came across a video suggesting the use of a wood wash to eliminate mold and moss from wood before staining or painting. I found a DIY that recommended using “oxygen bleach” – similar to oxiclean. I gave it a try (making sure to mix it in hot water), scrubbed it onto the wood, rinsed it off, and voila! The wood looked brand new without any discoloration. It was also exposed to the sun which may have helped. The whole process took less than an hour.
It’s probably mildew, not black mold. Home Depot has various products for this – I used one from the paint aisle called Mold Armor. It’s great for cleaning and killing mold on different surfaces.
Steel wool