Hello,

I'm try to clean up the shoddy work from the previous owner of my house. I currently have a plank floor (diagonal to the beams), on top of that I have a 1/4" plywood (not secured very good) which had tile that was cracked and really crappy. I want to install some 0.60" engineered bamboo hardwood, from what I read I should use 1/2" plywood over top of the plank. I was thinking about ripping out the 1/4" plywood, then screwing the planks down with some 8 x 2 1/2" decks screws. After I would glue and screw the 1/2" plywood to the planks. Does this sound okay? Also what direction should I install the 1/2" plywood and should I screw it into the planks or just to the beams, if so what size screws should I use.

And after all that work your going to install bamboo? Don't get me wrong, I love the look. As long as it's in someone elses house. I've put in a ton of it, and see plenty of problems. The problems aminly exist because of poor maintenance issues.

I'm pretty meticulous with my home (hence trying to do correctly, even if it is more work). What issues have you seen? What kind of flooring would you suggest? I have already bought the bamboo, but it can be returned. Do you think my process in regard to the sub-floor preparation is correct?

Nothing wrong with your planned preparation work. Once you have secured the planking to the joists there really is no need to fasten the plywood also to the joists. I would probably just staple the ply to the subfloor. No need to be overly concerned about which direction the plywood sheeting is installed either. Once you have removed the existing 1/4 inch plywood, this is a perfect opportunity to do any levelling required such as packing low areas or grinding down high spots before installing the new 1/2 inch plywood.

Thank you for the response, couple more questions. Do you think my screw selection for the planks are okay? Also what would you suggest use to build up certain areas before I put the ½” plywood down? I have read roofing shingles is okay. Lastly using this method would I be able to run the hardwood parallel to the floor joists?

#8 by 2 1/2 inch screws are fine. Try to avoid splitting the subfloor boards as you are screwing them down. If they are very dry and brittle with age perhaps a pilot hole for each one would be advisable.
One of the keys to a sucessful refit of a subfloor is often overlooked; hammering down all the existing nails prior to installing the new plywood.
Not sure about the code where you are but I think 1/2 inch plywood over conventional 3/4 inch diagonal board subfloor shoud be fine for parallel to joist installation, provided centrelines are 16 inch or less.

Sorry forgot the part of your question of what to use for leveling. Yes roofing shingles can be used, as well as any other non-compressible, non-degradable product you might have at hand, that will allow for through-nailing. Even multiple layers of flat cardboard (not corrugated) will do if not to bad an irregularity.

Thank you for answering my questions, i will have to see if the joists are 16" on center. With this strange house I hope it is.