Black spots on floorboards

[pwillems]

Hi all. Actively shopping for our cruiser, and have come across one that looks like it has potential. Looking at the photos, it appears to have a whole lot of black spots on the floorboards.




Is this a cause for concern? What causes this and how can it be corrected?

[Haylands]

A total guess, I could be miles out but they look similar to stiletto heal marks, where the wood gets bruised... could be damp spots though.... I suppose a strip and refinish would sort them, but you do need to find out what they are....

Rest looks lovely....

[HappyMdRSailor]

Can't tell from the pics, but nothing a refinish won't take care of...

[a64pilot]

I can't tell from the pics either, but they are just dark spots, not black?
Not mold is it?

[GordMay]

Originally Posted by a64pilot

I can't tell from the pics either, but they are just dark spots, not black?
Not mold is it?

Black spots are typically caused by humidity in the wood that is developing into mold or mildew.

[a64pilot]

I'm thinking dark spots may be bruises and you may can refinish and take care of that, but black is different and could be mold, but how to deal with mold inside the sole?

[Snore]

If the marks are surface mold, then before you go crazy try Chlorox spray, spray and wipe. Done.


What is odd is that you are only reporting spots on the flooring. This may indicate that the problem is in the bilges. Before getting a surveyor, I would pop some inspection points and see what is going on. Also look at the joinery where anything vertical meets the flooring, does the joinery show signs of water damage? If so that may indicate the boat had some standing water in it.

Recognizing that 98.75% of all brokers tend to misstate facts, ask the broker. Or have him/her ask the PO.

All that said, the cabin look nice! Although having the main display mounted perpendicular to the nav seat seems odd.

[GordMay]

Originally Posted by Snore

If the marks are surface mold, then before you go crazy try Chlorox spray, spray and wipe. Done ...

Clean the teak with a detergent, bleach and water solution.
Mix 1/4 cup of bleach with 2/3 cup of laundry detergent in a gallon of water.
Apply the cleaner to the wood with a bristle brush, and scrub affected areas in the direction of the grain to remove the dirt and mildew.
Then, rinse the floor with fresh water to remove any remaining cleaning solution.

[a64pilot]

Originally Posted by GordMay

Black spots are typically caused by humidity in the wood that is developing into mold or mildew.

Yes, but how do you deal with this? Mold on the outside of the finish would be easy, but mold inside of the wood?
I'm not saying the OP's problem is mold, but the title is Black spots on floorboards and black sets off my alarm.
For some reason I want to think chlorine (bleach) isn't really what you want to use on mold, I don't know why not and I don't know what you do want to use, but I seem to remember that chlorine isn't that effective?

[GordMay]

Originally Posted by a64pilot

Yes, but how do you deal with this? Mold on the outside of the finish would be easy, but mold inside of the wood?

Take an 8-penny nail with a sharp tip, and see if you can push it into the wood with just your hand. If you meet immediate resistance, the wood is fine. If the nail, using hand pressure, penetrates deeper than one-quarter inch, then you could have wood rot (mold In the wood). In this unlikely event, it will likely require replacement.

If you don’t like chlorine (or doubt it's efficacy), you also can use oxygen bleach. It's a commonly available powder you mix with water.
Stir until the powder is dissolved in warm or hot water. Pour this solution in a hand-pump garden sprayer and spray the black areas on the wood. Allow the solution to work. Keep the wood wet with the solution for up to an hour.
Stubborn mildew and mold stains may require some scrubbing. Rinse all the wood once it's clean, squeegee the floor, and set up fans to air dry the wood as rapidly as possible.

[bsurvey]

strip off the varnish then teka teak bleach, 2 part with bronze wool pad is the only thing that will take it out. be careful if this is veneer as it will eat right through

[tdoster]

First you have to know if the wood is solid or veneer. Many are just 1/4" ply with a very small layer of actual veneer. I have found that when this is the case, it is far easier for water to be trapped between the ply and the veneer causing the discoloration. This is compounded on older yachts when refinishing and sanding an already thin layer even further.

Dark discolorations are normally water in the substrate material or plywood below it if veneer. If solid, it would just be dimples from years of abuse that accumulate dirt and moisture and easy enough to refinish. Still a big job to refinish a solid cabin sole, but still less than replacing veneer and floor boards, though I have seen some boats where replacing was easier than refinishing when the sole is flat and cabinets not built over the sole.

[Terra Nova]

It is highly likely that the floorboards have been submerged from a partial sinking.

[Snore]

Originally Posted by a64pilot

...For some reason I want to think chlorine (bleach) isn't really what you want to use on mold, I don't know why not and I don't know what you do want to use, but I seem to remember that chlorine isn't that effective?

When I got my boat about 3 years ago, the overhead was disgusting; mold spots speckled the top like a mad case of measles.

I used clorox spray and only that to clean it. Spray, let set and wipe. Then spray, go sailing, spray and wipe. It killed all the mold. I still use Clorox to control mold. It is cheap, and requires little effort. Currently the overhead looks as good as the day Tartan delivered the boat.

While other concoctions may be effective, they require effort better spent sailing.

PS Practical Sailor dos a study a few months back that reached the same conclusion.

Terra Nova, doubt she sank but the source of the moisture is a riddle.

Sent from my iPhone- please forgive autocorrect errors.

[roverhi]

We must have a different definition of BLACK. Don't see any black spots on the floor just what look like what may be bruise marks from stuff dropped on the floor over the years. Can't be sure exactly what they are from the pictures but don't see any black at all. In any case, stripping and refinishing the floor may take care of the spots but not guaranteed. May require wood bleach like Oxalic Acid to blend them in.