Last weekend, I had to have the floor pulled up to fix structural problems resulting from a whole ton of rotten wood. It was pretty bad - I lost about a quarter of the "free" wood out of the scrap pile (one way or another I'm paying for it, so why not take some?) to rot. Either it was super brittle (healthy wood doesn't crack across the grain when pressure is applied), or it had tiny cracks across the grain when I picked it out, or it just crumbled with the tiniest pressure.

The areas around the fasteners was usually black. I'd assume this is from something leaching into the wood, or some sort of chemical reaction going on. Given that it happened the same with newer (less than 2 years old) wood from an earlier repair in the same section of floor (the contractor either had no idea what he was looking at, or it wasn't nearly as bad then) for a different reason the same as it did for wood that's been there likely since the house was built, I'm generally unconcerned.

More than a few boards were covered in this fine yellow powder, and one had some white fuzz on it. Reading around, I see that rot can result from fungal or bacterial colonization, and while I'd think it's pretty obvious that the latter is mold fuzz, I would think the former to be spores of some sort. Is there a product that I can use to keep whatever caused the rot from migrating to the other wood in whatever furniture I build with the stuff? The majority of it is 68 years old; it'd be a shame to have to scrap it all.

The waste (too rotten to possibly save) wood has been relegated to the firewood bin.

A photo of the yellow stuff

I am no expert at all, but I wonder if you could send them through a planer after cleaning with bleach to kill the mold or whatever. The planer would remove it all with the top layer of wood (and finish) and leave you with a "naked" smooth board.

Do wear basic PPEs, though. Gloves and a face mask at least.

 
That black stain might go pretty deep. You might be able to see on the edge, or sacrifice one board and cut into the black. If it is deep, you are never going to get that back to looking like oak, is my thought.
 

There are natural chemicals in the oak that react with the steel/iron in the nails that hold the floor in place. This causes the black staining. It may be very deep in the wood.

As for the mold, I would be tempted to let it dry in a hot barn loft kind of area for 6-12 months, then sand it and seal all sides with a penetrating sealer.

IMHO, bleach to kill anything. Wood bleach to normalize color where possible, maybe. Plane. Work with results as part of design.

Coloring can work to your advantage as part of a design, such as rustic low tables.

quote:

Originally posted by Chris42:
There are natural chemicals in the oak that react with the steel/iron in the nails that hold the floor in place. This causes the black staining. It may be very deep in the wood.

As for the mold, I would be tempted to let it dry in a hot barn loft kind of area for 6-12 months, then sand it and seal all sides with a penetrating sealer.

Like I said, I'm not worried about the black marks in the side/bottom. The coloring works well for the coffee table I have planned for it, and it's not visible on the top (other flat side). That's also what I thought was the case regarding what causes it to happen in the first place. The black stuff on the back there is either from the moisture barrier breaking down or contact with the subfloor, which was pretty gross looking and black.

Unfortunately, I don't have a hot barn loft area. I have a sorta-warm garage in an area that gets pretty humid in the summer. I do plan on sitting on the wood for a while regardless, if only to dry it out some.

Bleach does seem like a good idea. I'm thinking about setting the whole lot aside for about 3 months, perhaps with a monthly spray-down. I've got enough I can do in the meantime with my desk build still unfinished. I was simply wondering if there's a better product out there. Some places I've seen recommend polyethylene glycol, others say boric acid, and a few say ethylene glycol antifreeze (a suggestion that I reject flat out because of health risks). Some have suggested bleach as well. Regardless, it doesn't seem like a terrible idea to bleach it at least once to clean it up some.

Thanks for the suggestions, guys.