I think this is OSB based on the sticky thread but the flakes are smaller than the ones in the pictures. This is 3/4inch and is the subfloor with no underlayment on top. It is in house that was built in 1979 and is nailed to to floor joists that are 16 on center. Is it OSB?



If it is OSB, then I should be fine to lay 3/4 in harwood nailed based on what I have read. I am thinking about laying down underlayment to the floor because it has some dips in it and there is some bounce in the floor and I think it would help with the bounce and make it flat. I only have about an inch to work with in my door swing so the most I could use is 1/4 plywood otherwise I have to change out my exterior doors and sliders. Do you think think installing 1/4 inch is worth it and will help with the bounce and making flat? If there is another easy way to transtion and use 1/2 inch or better I am open to that I am just could not think of any beyond moving the door headers and resetting the doors.

thanks,

I know this sounds crazy but that picture looks like Cedar closet lining material to me, but I have never seen it in a 3/4" thickness. Maybe its Aspenite but I don't remember that being reddish looking. I am not helping much .

A 3/8" underlayment is usually the minimum for trying to stiffen up the floor system. If you have to use a 1/4" the low spots should be built up with layers of felt, roll roofing, or shingles between the subfloor and underlayment.

Thanks Jerry, so if it is Aspenite I assume that it is not sutible for hardwood? Does anybody know if there a good way to idenify this subfloor material or test it to see if its going to hold for nailing 3/4 in hardwood?

Thanks for your help!

if you can get a peice out you may be able to take it to the local lumber yard and see what they say about it. one other option would be using 1/2" flooring instead of 3/4 that way you could put down the 3/8 ply and still have your clearance needed.

It isn't OSB, which stands for Oriented Strand Board. I realy don't know what it is. It appears to be a conglomeration of a particle board subfloor material called "Red-X" and chip board. If you do not have the clearance for 1/2" plywood underlayment, then I agree with Kevin that you could consider using thinner flooring and the 3/8" or 1/2" plywood underlayment.

Thanks for your help. I will lay down 3/8 or 1/2 inch plywood. To make the floor flat can I use, shims, felt, and shingles between the subfloor and the new plywood or should I just use this after the plywood is down use it when I am installing the floor?

Thanks again,

Its aspenite .. they use it a lot here for sub floor because its cheaper then plywood ..

Floor Guy,
Do they still use that today or is it a product of the past that has been replaced by OSB?

Also, I found these articles about OSB, Aspenite and chipboard.
http://www.crmmodular.com/osb.html
http://www.umass.edu/bmatwt/publication ... ywood.html

Thats for the ID on that. I was assuming I could not lay on that but I was doing some searching on the aspenite and found someone saying you can.

http://www.homefocus.com/Default.asp?id ... 0&qna=9922

Is this incorrect? Can I nail to aspenite? I want to make sure I do it right and if that means laying plywood great, but if I don't have to lay plywood even better.

Thanks,

Well, that fellow is from Ontario, Canada. They have different ways of doing things up there and do not always agree with NOFMA or NWFA recommendations. NOFMA and the NWFA agree that the only suitable wood subfloor material is either solid board lumber, plywood or OSB. That rules out all other subfloor materials including Aspenite. The real reason for this is due to nail holding capacity. Independant testing has shown that over cycles of expansion and contraction, the fasteners are stressed and will lose their ability to continue to keep the floor tight if the flooring is installed over a non approved subfloor material. So, can you install over it? You certainly can and may. The real question is should you? And according to NOFMA and the NWFA, the answer is no. One thing that "expert" from Ontario is quoted as saying is that since you nailing into the joists, he is infering you will be getting additional nail holding from that. But that statement is untrue. If your flooring is 3/4" thick and the subfloor is 3/4" thick, very little, if any, of that staple/cleat/nail will protrude from the backside of the subfloor to go into the joist. So, it doesn't make any difference to attempt to nail where the joists lay. The 2" fasteners aren't long enough to bite into the joints anyway. This idea is a hold over from the days when floors were hand nailed with 2&1/2" flooring nails but do not apply anymore, unless you were to do it this way.

Thanks again for all your time and help. I will lay down plywood and do it right.

Gary , they still use it today .. in fact they even use it for the outside walls in new construction .. I used it to buld my brother a 20 x 20 shed .. used ply on the floor though .. its a strong product , but it will swell with moisture .. i used my porta cable 1 x1/2 stapler to fasten it , and we had to remove a sheet because he desided to put a large window there , what a job getting that stuff
off the studs .. it has good holding power ..

That picture looks like poor quality particleboard, where the coarse particles are at the surface. Normally the coarse particles are in the core, and the finer sawdust on the face. It is definitely not suitable for hardwood.

Aspenite, chipboard and flakeboard are often used as slang terms for OSB. If the board was made in the last 20 years it's probably OSB, older than that the strands/chips may not be oriented, and is not suitable for hardwood.

Thought I would let those that were interested know that after taking up the carpet I found the stamp. It was LP RED-X after all.

Thanks ,