Black mold on teak deck what to do?

My boats thick teak deck has black mold on areas that probably held dampness. How to kill the mold and clean up the teak. The wood is raw without varnise or sealer.
So what should I do? Will house hold bleach kill the mold?

Use as mild a cleaner as you can.

I'd try oxalic acid crystals first. Scrub across the grain as much as possible.

But with imbedded mold you may have to scrub with the grain to get it out. If so, use as soft a bristle brush as you can.

Once you get it clean you can keep it clean with regular wash downs with a mild teak cleaner.

You can also keep mold at bay by washing you decks with clean salt water and not rinsing it off but letting it dry out so the salt and other minerals stay in/on the wood.

If you're in a wet and rainy area fighting mold can be a very on going battle.

Use hydrogen peroxide, baking soda and apple cider vinigar. My wife took our cap rails back to beautiful warm teak. There is a thread on it. The black dosn't just disapear ... some work is required. Look for the thread.

But the baking soda in a container and slowly add ACV. use the tall cottage cheeze tubs. It will foam up some. Then add the HP. This is a very short blurb and you need to be careful as it's fairly strong stuff. Then a good ballance of agression re scraping. Do small areas at a time. She's talking to meand I'm pecking it down. Good luck.

Rebecca Whitman who wrote the bible on varnishing does not recomend the commercial chemicals.

TSP - trisodium phosphate

I used Concrobium mold control at home on wooden windows frame where some mold started to appear due to condensation in winter. At the beginning I was more than sceptical but I must admit I am greatly surprised. Cleaned the mold and for 2 years now no mold anymore.
Here is the description from a local store:

https://www.renodepot.com/en/mold-control-spray-4232001

Greetings,
...and here's the MSDS for the product in post #5 http://www.concrobium.com/wp-content/uploads/2012/05/Concrobium-Mold-Control-MSDS-US-2011.pdf
I was curious as to the makeup but it seems there's not much in it????

Hi, This product BORACOL 10 is good, is this the U.S.? In Europe, the popular stuff!






https://acslimited.co.uk/boracol


Halsberg rassy say:
"In the long run the best way to treat the teak deck against
mildew is to use Boracol. Boracol is a liquid that is uncoloured and thin like water. It is sold in normal
chemist shops and hardware dealers. It is marketed as a treatment against mildew for garden furniture.
Use a normal paintbrush and paint the deck with Boracol. Never use a normal brush on the teak! Do
the work on a dry dray. If it rains too much Boracol will be washed away. It does not matter if it is
drizzling the next day but if it rains the complete day or over splashing waves washes over the deck, the
Boracol will make no effect. That would flush the Boracol way too early. If it does not rain, spray the
deck a little with water. This little amount of water only helps the Boracol to penetrate into the teak.
After three to seven days you wash the deck with a sponge and cleaner, for example green soap. Please
do not be afraid if you do not see any positive result immediately. On the contrary, the deck looks
worse than it did before the treatment. After about ten days things will start to happen. The mildew has
disappeared and the deck is clean. The mildew will not recur for some time. Do not be afraid to repeat
the treatment now and then."

RT Firefly said:

Greetings,
...and here's the MSDS for the product in post #5 http://www.concrobium.com/wp-content/uploads/2012/05/Concrobium-Mold-Control-MSDS-US-2011.pdf
I was curious as to the makeup but it seems there's not much in it????

Click to expand...

I confirm, no odor, no vapour or cov of any kind and it is mentionned that it is safe for human and even to use in places like kitchens. The only thing they mention is to be careful when first cleaning the mold to not inhale it as spore may be dangerous. Usage is simply clean the apparent mold with a rag, spray this stuff wipe, spray again and let dry.

You forum members are great and thank you so much for the helpful info.
Enjoy each day.

alormaria said:

TSP - trisodium phosphate

Click to expand...

Ouch! Only as a last resort.

And it will darken the wood so you'll have to bleach it out.