I've finished pine planks that were a subfloor before, and also have laid plywood ripped down to 24in wide and then finished it. Its a different look and not something i would put in my own house, but job turned out pretty well

I'm not a pro, but when we discovered tongue-and-groove pine under the original 70+ year old linoleum, we had it refinished and it turned out well.

On the flip side, I've seen clients who finished their subfloor with floor paint or urethane/polyurethane (I've seen this done with both concrete and plywood/OSB) to save money - and then try to put down a new floor a few years later (spend money they now have).

Each and everyone of them was devastated to learn that their "cheap and cheerful" paint job (which stood up well and had done the job they wanted) was now hindering their efforts to put in a permanent floor - such as glue down cork, vinyl, linoleum or mortared tiles such as porcelain/ceramic/stone.

The only thing they could do was float a floor over it. Which is exactly what they DIDN'T want to do. They also did not want the hassle of adding a layer of new plywood (because they had all the floors relatively level at that point) nor did they want to remove the layer of painted subfloor (some forgot they needed 2 layers of subfloor before they painted...so they had painted the subfloor layer that was directly attached to the joists = dangerous to remove and relay over open joists).

Painted or finished subfloors - so long as they are the required 2 layers as per Best Building Practices - are fine. They work. They get the job done. But they can HINDER the next step in the evolutionary process of a home. They can cost MUCH MORE then originally planned because of the "fix" needed to deal with them later.

I recommend that clients plan, plan, plan ahead. I would offer a word of caution: Realize what you are DOING to yourself - not just for today but for tomorrow as well.

All that being said, there are some PRETTY COOL things you can do to finish the top layer of subfloor/underlayment. Good luck with your article.

There is a difference between using the actual laid subfloor and using subflooring materials as the finished floor. Very few sub floors are even paint grade without seeing through in spots to the lower floors.

Why would you promote in fancy well staged pics how great your dolled up subfloor looks from 10' away? Its a subfloor and it is not installed in a manner that would allow it to function as a finished floor. Nails, cheap wood, spacing, etc, etc.

Stop promoting half done nonsense that looks good in pictures.

I have done this for several clients... all came out great. One was particularly challenging, as the subfloor was not T&G and I had to figure out how to fill the gaps to prevent air from coming up from below and stuff dropped on the floor from falling through to the space below. I chose a flexible brown caulk that would be compatible with the waterborne polyurethane. I first shoved polyurethane backer rod between each plank and then topped that with the brown flexible adhesive acrylic caulk. It worked. The floor was finished natural and had this great contrasting brown line separating each plank.

Another one was an attic floor that the client wanted stained green and finished. She loved her green Pergo floor in her kitchen and wanted the attic planks to resemble it. The attic floor surpassed the Pergo floor in final appearance.

Unfortunately I never photographed those jobs.