I have a 125 year old house in mo and found on the third floor there is 1 inch thick x 3 and 1/4 tongue and groove (oak???) under the carpet that I removed in one room. I assume this runs throughout the third floor under the carpet. The floor runs the opposite way as the joists and is nailed directly into the joists with old square head long nails. I have to replace a couple broken boards but otherwise the flooring would look good after a sanding. Since its on the third floor and I don't have the moisture or temp issues, am I ok with refinishing it or could it just be an old subfloor?j

Hello forum, I've been searching the web for quite some time now, looking for the most consensus on how we should go about replacing our old flooring. I have settled on this forum as many of the threads seemed relevant and I liked the specific advice given! Please advise on our situation (I will be taking measurements and photos tonight so as to include additional information) We bought our first home, and it's 104 years old. We've started remodeling the kitchen. We've ripped out every appliance, cupboard, as well as 3-5 layers of old flooring. We're down to the original floor/subfloor that is tongue & groove planks. This is over a basement, and when you leave the lights on in the basement, the kitchen floor lights up like the night sky from the nail holes. I have purchased 5/16" bamboo flooring and now I'm debating how thick of a plywood I have to get? I was pretty set on 1/2" until I read some more about possibly using 5/8" or 3/4" even if our joists are too far apart. Once I have measured the distance of the joists (which I think will be far given other threads/house age) Can someone confirm if it's honestly ok to use the 1/2" plywood over the old planks? I'm on a really tight budget, so if at all possible I want to stick to 1/2" but I don't want to redo the floors in 2 years.