I am going to replace the hardwoods in my 1930 house (current hardwoods are 1/4 inch thick and trashed!)-just moved in and checked the subfloor. It is 3/4 inch thick by 5 inches wide plank that is tongue and groved, perpendicular to the joists ( i have no idea what kind of wood it is). I plan on 3/4 inch oak solid floor.

Assuming I tear up the old hardwoods (which brings up another question-anyone have any good ideas on how to do this without tearing up the sub-floor as well?) and re-screw the planks into the joists, is my subfloor OK for installation?

Also, my current hardwoods (it is like 1 inch wide face nailed stuff) are aligned parrell to the joists. I have heard this is frowed upon, but because of the layout of the room this looks the nicest and I don't want to run into the problem of nailing where the sublfoor planks butt up if I went the same perpendicular direction of the subfloor. Is it okay to go parrell to the joists? (i'm gonna be using 3 1/4 wide oak, possible 2 1/4).

Thanks for the help!

Nick

Just pry up that old 5/16" face naile oak floor. Pound down any nails and renail that plank subfloor (or use screws, whatever). Then install a 3/8" minimum ( 1/2" is prefered ) plywood CDX underlayment over your plank subfloor by stapling well with a 16 gauge x 1/2 crown contruction stapler. If all is flat, level and sound, you are ready to install that new oak floor in any direction you wish.

Thanks for taking the time to respond Gary.

The floor looks flat, but I imagine there are going to be some areas where the home has settled over the years and is not perfectly flat. Before I put the plywood over the plank subfloor, is there any type of leveling compound (I wouldn't think shims would work) I can use to level out any uneven spots on the plank subfloor before I put the CDX on?

Nick

Don't use any leveling compounds for nail down floors or underlayments that are to be fastened with nails/staples/screws. What we use is asphalt roofing shingles; the cheap 3 tab version and 30 lb. ashalt felt layered up. However, don't go thicker than three shingles. If you need to go thicker, then you'll need to use plywood and/or wood shakes. After everything is flat and secure, lay your plywood underlayment and staple the snot out of it, or screw it down. Either way.

Gary without you this forum would not be the same!

Last round of questions for a while I promise:

#1-When using shingles or folded felt paper to level areas on the sublfoor-what should you use to secure these materials-just regular old staples?

#2- Does the plywood overlayment need to "acclimate" as well for a week or two after installation?

#1 I just use a hammer tacker. It bangs in staples 1/2" long. The brand I use is a Duo-fast the carpet installers use for carpet pad. The staples are super sharp. Hammer tackers work great if you get a good one. Since you are installing plywood over it, all you need to do is hold it down in place. No need to go bizerk here.

#2 No. Just install the plywood. HD and Lowe's store it INSIDE the store, where it should be. But moisture test it prior to laying your new floor. Should register around 10% MC, + or - 2%.

Thanks for the compliment. I do what I can. A lot of the guys here know as much or more. They just got more responsibilities than me and not as much time to type.

That may be the case Gary but thanks for taking the time and doing the typing. My project comes up next month and I am glad I am a little smarter to relate to the installer.

So I just picked up some 3 ply 1/2 CDX plywood....in many of the sheets there are knots that have fallen out of the outside ply (like some of the sheets will have 3-4 "holes" that are 2-3 inch in diamater). Some of them have them on both sides so i can't get rid of it...are these going to be a problem? Should I fill them with the felt paper?

Also, will screws every 6 inches be fine to ensure good attachment with the old subfloor?

Nick

Those knot holes in the plywood will pose no problems; just ignore them. Screws 6" OC should be fine

To what maximum height should i use shingles to level, as opposed to plywood?

It appears i have a few low joists in the middle of the 2 rooms i am doing and it causes the floor to taper into the middle where these joists are about 3/8 (possibly 1/2 in some spots) of an inch over like 4-6 feet. Should I use plywood to shim it in the middle (then feather it out using combination of shingles and felt) or should i just shingle/felt it? Damn old houses and all there "settling"!

Nick

Shimming those low spots is a major pain in the butt. With a 1/2" low spot, you need to use a wood product like plywood and keep tapering with thinner plywood and a combination of shingles and felt. You could try to glue and nail one size of plywood and sand that flat but that's a big hassle as well. I've done it both ways. One last option is to GENTLY pry up the subfloor boards and add furring strips to the tops of the low joists. All ways are a pain. Good Luck.