18"-wide red oak flooring...Question about the subfloor.

[Dodgy Loner]

I've got a stash of 18" wide red oak boards that I want to use for flooring in my kitchen. I plan to face-nail them with cut nails. Problem is, my house was built in the 1970's, during an era when people liked to put a nice layer of particle board over the plywood subfloor before framing the walls . I'm wondering if I should bother to take up the particle board before laying the flooring. Logically I think that I should, but I just know it's going to be a huge pain in the arse (I've already had to take it out of a bathroom before laying tile). I'd also be interested if anyone could tell me what the point of putting a glorified sponge on top of the subfloor was in the first place .

Also, on a related note, does anyone in my vicinity have a 20" planer handy ? I don't think my 12" DeWalt is going to cut it (pun intended ).

[beenthere]

.......... if anyone could tell me what the point of putting a glorified sponge on top of the subfloor was in the first place .
........

Done as an underlayment for stiffness and a more even floor, usually because the plywood alone was not stiff enough (for carpet, vinyl, or tile) by itself. Is the underlayment glued to the plywood...hope not.

Your oak floor sounds quite interesting. Enjoy the challenge. 

[Dodgy Loner]

No, the underlayment is not glued down, thank goodness! But it is very tough to remove because a circular saw can't get close enough to the edge of the wall. I ended up having to chisel out the stuff all along the perimeter of the bathroom that I remodeled. The toilet had leaked in there and the particle board swelled up to twice its original thickness, which is what prompted me to remodel . I did notice that the plywood subfloor in my house was thinner that what is used today. 5/8", I think. Why couldn't they just use thicker plywood? Oh well, what's done is done, but that doesn't mean I have to be happy about it

[Tom]

I can think of no use for particle board.  It won't stand water and won't support weight.  It doesn't wear good and I'd be afraid of it in a housefire.

With that 5/8 plywood as a subfloor, the 1" oak you want to put down should make a floor more sturdy than most modern floors.  What you really need is something that will hold the nails and help support the weight between joists.  3/4" might be better but most flooring today is not 1" either.  The floor that I'm familiar with was wide pine boards glued and surface nailed to 3/4" plywood.  It's like walking on terra firma.

[Fla._Deadheader]

 There is s small circle saw, that is used to undercut door jambs and base moulding, for installing new floors, such as tile. It cuts VERY close to the wall, so, it might get you close enough.  I once modded an old Skil saw to do that same job. Just cut away nearly all the outside blade guard, and lay the skil saw on that side. It will nearly skim the floor, if you are careful. Stand it up as normal to cut the floor.

  Slide it along the baseboard. Finish with new moulding over the joint. Never know the difference.

[scsmith42]

Dodgy, if it were me, here is what I'd consider...

1 - remove the partical board and smooth the top of the existing subfloor.
2 - install additional 3/4" subfloor on top of the existing subfloor.  Stagger the joints, and use construction adhesive between the sheets and in-between the seams between the new sheets.  Use either Advantek or Plytanium for the new subfloor.
3 - Resaw your boards to 1/2" thick, or thereabouts.
4 - Plane them down to 5/16" - 3/8", and straighten up the edges with a horizontal resaw.
5 - nail / glue them to the subfloor with an excellent flooring adhesive.

In essence, by using this process you are manufacturing your own engineered flooring in place.  The combination of thin oak boards, a strong subfloor and high quality flooring adhesive serves to control the expansion and contraction on the floor, eliminating the gaps between boards as well as doubling the sq footage that you can cover with your boards.

Good luck with your project - ought to be spectacular.

Scott

[Larry]

I’ve been researching underlayment for hardwood flooring on a slab.  I was hoping to use OSB as it is so much cheaper than plywood.  The only thing the oak flooring manufactures association will recommend is 3/4" plywood for its nail holding ability.

In my last house I used 3/4" plywood for the sub floor with oak strip flooring.  In the kitchen and bathrooms on top of the ply I used something called underlayment.  It’s a thin plywood to provide a smooth base for the linoleum tile...I suppose your mdf served a similar purpose.

There are tools to cut close to your wall...check out the rental places.

18" wide flooring sounds most interesting...and way to risky for me.  Take pictures and let us know how you progress.

[Fla._Deadheader]

 In coastal Central Florida, ¾ ply is nailed directly to the concrete floor. Then, Hardwood is nailed to that. We ripped up bunches after the Hurrykanes left town. Don't remember any tar paper or other water resistant barrier. This was, only multi million $$$ houses, after all. 

[ladylake]

 Up here in MN if we put down 18" wide flooring we'd end up with a 1/2" crack in the winter and no crack in the summer due to wood movement.    Steve

[DR_Buck]

I’ve been researching underlayment for hardwood flooring on a slab.  I was hoping to use OSB as it is so much cheaper than plywood.  The only thing the oak flooring manufactures association will recommend is 3/4" plywood for its nail holding ability.

In my last house I used 3/4" plywood for the sub floor with oak strip flooring.  In the kitchen and bathrooms on top of the ply I used something called underlayment.  It’s a thin plywood to provide a smooth base for the linoleum tile...I suppose your mdf served a similar purpose.

There are tools to cut close to your wall...check out the rental places.

18" wide flooring sounds most interesting...and way to risky for me.  Take pictures and let us know how you progress.

You don't want to use OSB.  Moisture from the slab over time will cause it to expand and deform.  Then your fasteners will start to work loose.   I sealed my dining room slab, then screwed 3/4" exterier plywood to the concrete.  I treated the plywood with a wood preservative on the bottom side.

[WDH]

An ambitious project, Dodgy (one who does not follow the well beaten path, instead, forges his own ).

[LarryRB]

Are you sure the second layer go under  the walls? When we uses to add a second layer it was alway after the house was framed and we put it down before triming.

[woodmills1]

I almost always run my flooring perpendicular to the floor joists.  I snap lines on the floor where the joists are, and put my nails along those lines, through the sub floor and into the joists.  the only nails that are into the plywood only are those at the ends of boards that don't fall on a joist.

[Dodgy Loner]

Up here in MN if we put down 18" wide flooring we'd end up with a 1/2" crack in the winter and no crack in the summer due to wood movement.    Steve

Well, I should have been more specific, but 18" was the green width of the boards. They are under 17" right now and will probably be down to 16" once I straighten the edges. The moisture content of the wood in my house varies from 8 or 9% in the winter to 11 or 12% in the spring, then it dries out again when I start running the A/C in the summer, so I don't expect much more than a 4% change in moisture content throughout the year. Change coefficient for red oak is .00369, so [4% x .00369 = .01476 x 16" = .2362"]. In other words, the change in the width of each board should be just under 1/4" (0.25") over the course of a year. I can live with that.

Are you sure the second layer go under the walls? When we uses to add a second layer it was alway after the house was framed and we put it down before triming.

I'm positive. I know it doesn't make sense, but few things in this house do.

I almost always run my flooring perpendicular to the floor joists.  I snap lines on the floor where the joists are, and put my nails along those lines, through the sub floor and into the joists.  the only nails that are into the plywood only are those at the ends of boards that don't fall on a joist.

That is what I plan on. I suppose I'll have no choice but to remove the particle board, because the nails wouldn't reach much into the joists if I don't . I will just have to get one of those small circular saws that FDH mentioned, even though I hate having to buy new tools. [sarcasm ]

[woodman58]

Dodgy, I am a hardwood flooring installer. The only reason the partical wood should come up is because flooring nails are not long enough to get a good bite into the bottom layer of flooring. You said you are not using flooring nails. You should be able to go over the partical wood using nails long enough to go thru both floors.You will also need to use glue. National Wood Flooring Assocation says to use glue and nails on any wood flooring over 5 inches wide. You can use liquid nail and put a bead about every 6 to 8 inches. This keeps the floor from cupping.

If you choose to remove the old floor, Harbor Freight has a TOE KICK SAW (http://search.harborfreight.com/cpisearch/web/search.do?keyword=toe+kick+saw&Submit=Go) for a good price. I don't think it would be for every day use, but it will be good for what you need. It gets right up to cabinets and walls. It will not go all the way to the corners. They have a saw that is like the Fein cutter that will finish to the corners.
Hope this helps. Paul

[Dodgy Loner]

Thanks for the info, woodman! I think I will take the particle board up, if for no other reason than to prevent a repeat of the issue I dealt with in the bathroom when the particle board got wet and swelled up. The saw you linked to looks like just the ticket

[trim4u2nv]

Just finished a kitchen floor and this saw will cut into tight corners and under toekick overhangs.

http://www.tylertool.com/rk5100k.html?gclid=CKHaiZbhtp8CFRIMDQodajWc4A

[solidwoods]

Keep the floor to minimum # of layers.
No particle board.
Solid wood subfloor is OK if the boards are s4s  (t/g'd and diagonal layed is better).
Lowering floors is easier than raising them because of door/trim clearances.
I like a floor with no thresholds in room to room doorways also.
Water based topcoat is a good way to go. from  hoodfinishing.com
And aniline dye if your coloring.
Champherd edge would be a consideration also.
For end to end joints- Biscuit/glue or  router made dado with a floating tenon (made to fit the dado's on the board ends) glued also.
If you could get the show face sanded to thickness then go to t/g.
How are s4s'ing?   shaper with pwr feeder 4 side moulder?
I didn't catch your qty. but shopping for the nearest   suitable milling shop may get the job done quick/good/worth it.
Also being wide boards I'd look at the longest tennon I could find.
jim

[petefrombearswamp]

I live in central NY state, lots of humidity change from summer to winter.
Don't know about RO but my floors are 18" White Pine in the bedrooms, 4 to 9" wide Cherry in the living room, hallways and den, 3 to 7" wide Hard (Sugar) maple in the kitchen/ dining area.
The pine was air dried and the hardwoods kiln dried.
All is T&G, with floating tenons on the ends and installed by screwing up thru the sub floor of 3/4" plywood from underneath.
Very pretty with no fasteners showing.
These floors were installed in 1993 and I now have a couple of boards that have started to squeak in the heavy traffic areas.
There is seasonal movement in all floors with not surprisingly, the pine moving most with about 1/8 gaps appearing.
A mistake my finishing guy made was using a water based finish called Pacific Strong. It sure is.
The finish was applied when the joints were tight and as a consequence, the top of the groove has torn loose on several boards due to shrinkage. This tearing is the wood not the finish.
Where? right in the most noticeable spots of course!
Good luck with your project.
Pete

[Ole CB]

I'd also be interested if anyone could tell me what the point of putting a glorified sponge on top of the subfloor was in the first place .

  As an old carpenter, in 1966-70 I recall putting down 5/8" partical board on top of 1/2" plywood. We laid the 1/2" ply, built the walls and after drying it in (ready for sheetrock) we'd go back and lay 5/8" partical board between/around the walls.  Seems like 3/4" ply wasn't as easily available (or too costly) and we used a quality 4 ply plwood subfloor. You have to understand that in 1960's plywood was the new deal. It wasn't long afore that we used 1X12 sub and T&G flooring above it. Check your counter tops it was usually made of a high grade partical board and went right up to the kitchen sink. We used the same grade of PB for the flooring. We even used the partical board in the bathrooms where apparently aim wasn't a problem back then.....(For me now it is.. freakin bifocals anyways!!) Anyway at the time, that was the way it was done!!!

[Handy Andy]

  OSB won't hold a nail, use plywood or solid wood under hardwood flooring.  Some guys use glue over osb, but still not as good. When I did my oak flooring, I laid on the diagonal, and put screws in the plywood first to get rid of squeaks. Even in spots the screws didn't help, the oak doesn't squeak.  The house was about 20 something when I laid the oak. Had a few squeaks under the carpet. Don't notice any now.

[Dodgy Loner]

The house actually doesn't have any OSB in it. It was built before OSB even existed. The subfloor is plywood and the underlayment is particleboard.