Hi guys, I have been lurking for quite a while and have gained a lot of answers by doing many searches. I am now finally about to lay my first floor and need a little advice. My house is roughly 100 years old and the subfloor is very dry and brittle. I was planning on laying an additional subfloor over the existing one. I am going to use 5/8 t&g. I would like to screw the existing subfloor down and then screw the new subfloor. The old subfloor is so old that it seems to crack in all the places I attempt to screw down especially near the ends.

1. Should I continue doing what I am doing and hope some screws hold?
2. Should I forget about screwing down the original subfloor and just lay the new t&g and use extra screws.
3. Will this take care of the anticipated squeaks?
4. Should I bite the bullet and remove the old subfloor and sister in new joist to remoce a little sag and be done with it?

The room is 12 x 16 so not a huge room but I know I really only have one shot at this so i want to get it right.

Ang

Well it's now almost June of 2011 and you posted this in Nov. 2010. What did you do and how did it go?
I'd have said if your existing sub-floor cracks and breaks when you screw or nail it tear it out.