Here is the partially completed floor. Take a close look at the original, 101 year old plank floor. These planks are old-growth wood, which is incredibly strong and has shown great rot and mold resistance. These planks are 7/8" thick. The old subfloor rests on joists that are spaced 18" apart. I put in >5000 new ring shank nails to tighten this down in order to prepare for the installation of the new subfloor. I chose to use Advantech 23/32" OSB. It has an increased moisture and water resistance. This is important since the basement is a "fieldstone basement" and is a wet basement. This means that the basement is not (and will never be), water-tight.
Here is another view. Note my tool room. This has steadily filled up as I've gotten further into the renovation project. The halogen light is for when I work at night. Also note my shop-vac. I've filled and emptied this several hundred times in the past 6 months.
Each sheet of OSB / Advantech is glued and screwed down. As well, it is "tongue and groove", meaning that the edges of the sheets fit together like Lego, increasing the rigidity of the final floor.
Liquid Nails! This is the glue I'm using to hold down the flooring. After this, I lay down the sheet, then use a laser and pen to mark screw holes along the joists. This has to be exact, or else the screws will not have anything to bite into and the floor will exhibit play / movement and will likely develop squeaks.
Several sheets further along. Starting to look much nicer!
Here is a close up. OSB joints are offset, which improves rigidity. Note the screws. Each one is aligned by laser, then hand-marked. Next I pre-drill each hole. Then I switch to an "impact driver" and drive in 3" composite deck screws one-by-one. This floor is not going anywhere!
Each sheet is cut to line up with the new 2x6 framing. I'm done about 80% of the first floor now, and will try to finish it early this week. This will lay the right foundation to install my Noritz combi-boiler and baseboard hydronic heaters. With the recent New England snowstorm, some heat in this house would be very welcome. I'll take photos tomorrow and post them to show how much snow we've gotten... it looks like a lot!