adding finish does nothing to protect moisture from between boards. Flooring expands and contracts and gaps will occur between seasons. This is normal. There is no miracle product that will give you a seamless floor. You'd have to have a substantial 'leak' to do long term damage and if that were to happen you just need to replace the board or two that was damaged.

Boxers, Would it work, for extra protection, to take the pieces that will be around the wet areas and finish all their raw edges with wax, tung oil, polyurethane, or such, before installing them?

Evamommy, In my two kitchens with hardwood, the problem was not so much getting between the cracks but sitting on the finish. Family members who don't wipe up splashes, dogs drinking water, etc. After ten years we had a couple of these boards replaced, as boxers says, and it was fine. The finish of the new board was brand new and that fact did show up in the color of the wood and the fact of a brand new vs. a ten year old finish, but that didn't bother me, after all this is wood, a natural product. Finally, when it got too bad, we just had someone come over and distress it, and the distressing covered the bad spots. It was engineered with nothing really to re-sand so he did not strip it down, he just put a coat of stain over it, and a couple coats of poly over that. Then we sold the house and moved!

Kahrs, one manufacturer of prefinished hardwood, did recommend adding a coat of finish to seal the edges of water sensitive species after the installation was complete. I did that a few times.

Coating these new factory applied finishes requires special preparation with the correct chemicals and synthetic abrasive pads and then the application of a finish that will bond to the factory coat.

Probably best to just not let water spills and events sit on the flooring for a long length of time.

I would trust Glens recommendations. I've worked for Bruce, Hartco and Robbins so was sort of indoctrinated by the factory finish guys. There just is a lot of misinformation out there on flooring.

What Boxers says is also true. Wood does expand and contract and that is why sealing only works "to a certain point"...and shouldn't be relied upon as a cure-all to the fact that any wood floor has hundreds of seams, any one of which can allow water to seep down between the boards.

Boxers gives good advice and I value his comments. I don't want anyone, especially Boxers, to think I meant any disrespect.

Is there any reason I can't use prefinished hardwood on a covered porch (outside)? I can get this for a fraction of the cost of the T&G pine that they normally use. Any thoughts?

I sealed my prefinished floors. Here’s a link for prefinished hardwood floors check out what I did here https://youtu.be/M67ZF2exWQc

If you are going to all that trouble to use filler in every single bevel between each and every plank on your floor (?thousands of bevels to fill?) you might as well go with site finished flooring rather than factory finished floors with the beveled edge.

But then again I'm lazy...and would never have the need to "seal" the edges of a wood floor. If I had that need, I would probably work with tile.

Did anyone notice my tile to wood transitions?