I am about to install hardwood floors in 3 rooms where there were previously carpets. One of the rooms will be solid 3 1/4" maple and the other two will be solid Brazilian cherry. Both will be finished in place and not pre finished. The existing subflooring over the joists is 3/4" T&G pine CDX plywood with 5/8" particleboard over that. I want to avoid taking up the particle board if I can because its a lot of work. Heights of doors and moldings is not a problem because the carpet and pad height was about 3/4" My question is can I install the hardwood floor over the existing particle board and if so what should I use for fasteners. I was going to buy a nailer after I recieved a response on what to do. I am a contractor and very experienced wood worker and period furniture maker so I have the compressors and hoses. thanks in advance for any advise. Scott

Scott here again. I did just see the sticky about the subfloors which addresses particle board. but I still wonder if I can go over this floor because I am thinking the 2 inch staple will be long enough to go through the particle board and hold into the 3/4" plywood floor below. Any thoughts on this. Thanks Scott

NOFMA says not to install over particle board. The NWFA says the same. So I'll just repeat what they say. Read this:
http://www.nofma.org/CertificationGradi ... fault.aspx

Thanks for your response Gary. I knew that was the answer and I know this subject has been sufficiently beaten to death on this forum. I will go ahead and tear up all the particle board. The only reason why I even asked again is because I thought that if the nails are going through the particleboard and into the plywood I should be OK> This would be exactly the same as nailing into just plywood and perhaps better. It makes a lot of sence in theory but in reality its not worth the risk . A little more work will guarantee a job correctly done. Also the staples will go in on an angle and therefore may not go all the way through the plywood. My particle board was fastened to the sub floor so securely with ring nails shot every 6 inches on center the job is going to be H E Double hockey sticks. they go in a lot easier than they come out. Also the particle board extends under the baseboard so that should be a lot of fun. Thanks for your reply

No, it is not exactly the same nor is it better. I'll explain why. Particle board does not have the nail (fastener) holding ability that is required for hardwood flooring. Since the fasteners are installed at approx. a 45 degree angle, they only protrude about 3/4" past the bottom of the hardwood flooring. Since your particle board underlayment is 5/8" thick, only about 1/8" of fastener will be going into the plywood subflooring. This is insufficient for hardwood flooring. One final thought. You can and may do anything you want to. The question always is should you. Any true professional should adhere to industry standards. NOFMA, MFMA and the NWFA set the industry standards in the US. Other countries have their own standards. It would be irresponsible of us professionals to suggest that one should go outside of those standards.
Demolition is hard work, I know, I've done plenty of it.

Hi Gary. thanks for your response, I understand and that makes total sence. I completely agree with you and will take your advice. I guess I was just hoping that if I asked again the answer would change. I will definately tear up the particle board subfloor. Thanks again for all your help.

One final thought. I know that you cannot get any longer than 2 inch nails for a pneumatic nailer or stapler. I was just wondering if the manual nailers make a 3 inch nail. Someone else mentioned a 3 inch nail in a previous post but I have never heard of such a thing.
Scott