Considering the most often asked qusetion when it comes to nailing or stapling hardwood floors is what kind of subfloor is proper, we've placed this message in a "sticky mode' so many don't have to hunt for the answers.

More information on the subject within our site at these links:

Nailing or Stapling Hardwood Floors
Layout- Which Direction To Install
Subfloor Preparation-Tolerances
Racking Out The Floor

Pictures tell it like it is.

You don't want to nail or staple hardwood floors into this. True particle board does not have the capacity to hold nails or staples.





If you have a subfloor that looks like this, you may be able to nail or staple hardwood floors into it. Always consult the individual manufacturers specifications.





Anyone wishing to offer other tips, suggestions, ideas, corrections please let us know.

Contribution From Gary of Antioch CA

Added to this thread--January 8, 2004

Posted: 30 Dec 2004 08:59 pm Post subject: Wood Subfloors

--------------------------------------------------------------------------------

Since this topic comes up alot and there has been some misunderstanding and misinformation, I thought I would clarify it for you DIY'ers out there.
First let's talk terminology. It is importamnt when asking technical questions. So................
Subfloors......... Are the deck/wood floor a home is built on. The subflooring can be different materials and is always attached directly to the joists/trusses. Go in your basement/crawlspace and look between your joists. That material nailed to the tops of your floor joists is your subfloor.
Underlayment.............. If your have a vinyl floor in your home and you have wood subfloors, most likely you will have underlayment. Underlayment is used to provide a smoother substrate for some floor coverings, like sheet vinyl. It is also used to raise one area up to be even with another floor. It is used to provide a suitable substrate for tile ( like Hardi Backer Board) and used to stiffen the subfloor. It comes in many types: particle board, plywood, OSB, cementious tile backer board, sheet rock has been used, luan, masonite, etc. And more are being developed all the time. Underlayments are not subfloors and subfloors are not underlayments. Underlayments can be safely removed; subfloors should never be removed EXCEPT for damage or remodeling and only by licensed, knowledgeable contractors. Underlayments always go on top of subfloors and are usually stapled but can be nailed, glued, screwed, etc.

As far as wood subfloors go, this is what NOFMA (National Oak Flooring Manufacteres Association) and NWFA (National Wood Flooring Association) have to say. All solid wood floors should be nailed down (nail, staple/cleat) to an approved wood subfloor. Approved wood subfloors are listed in order; best to least preferable.This is based purely on the materials nail holding capability.
BEST: 1" x 6" solid #2 or better douglas fir or frame grade pine boards installed diagonally across floor joists 16" oc.
NEXT: 3/4" T&G Sturdi Floor plywood subflooring installed at 90 deg. to joists 16" oc.
Next: 5/8" T&G plywood subfloor installed at 90 deg to joists 16" oc.
Next: 3/4" OSB (Orientated Strand Board) T&G subflooring installed 90 deg to joists 16" oc.

There are other, older and not used anymore subfloor systems one may encounter. Such as: 1&1/8" T&G plywood subfloor installed at 90 deg to 4x6 beams spaced 4' oc.
1&1/2" x 5" T&G solid fir deck boards installed at 90 deg. to 4 x6 beams spaced 4' oc.
1x8 solid fir/pine boards installed at 90 deg to joists spaced 16" oc
1" RED-X T&G particle board subfloor installed at 90 deg to joists spaced 2' oc.
3/4" or 5/8" particle board found mostly today in modular and mobile homes.
These subfloors should NOT be removed but overlayed with 1/2" CDX plywood that is well stapled (2" around perimeter and 6" oc.) or glued or screwed. In all cases, subfloors and underlayments are to be flat to within 3/16" in a 10' radius.

When gluing down an engineered floor over a solid lumber subfloor, you will need an underlayment of 3/8" plywood, at least. When gluing down to a plywood or OSB subfloor, many are tempted not to use an underlayment. I prefer to use a 3/8" plywood underlayment over a plywood subfloor when gluing down a wood floor because if the floor needs to be repaired or replaced, it is easier/better with underlayment than with the subfloor.

I hope this clears up many of your questions regarding installing wood floors over wood subfloors.

Regards, Gary

Test

test what?
Ken, you may want to explain more about the Particle Board as to approval or not..... just a suggestion,
and, how have you been?
slt

Lee:

Feel free to add your knowledge. That's why this board is here. Thanks for visiting:)

5 year old house with carpet, and tile demo for prep of hardwood. Has what measured out to 2X10 fir running perpendicular to the joists, have to remove hardy backer/tile and particle board/ carpet.
Can I go right over those 2X10s with a sand in place, running across subloor, thanks!

How far apart are the "joists" spaced? Are the planks really 2" x 10" ? Are the subfloor planks tongue and grooved?

I wish I would have checked the joist spacing. They are not t and g, and they were ~9.5"X~1.5" thick, Have you seen this before Gary? THanks

The only 1.5" thick subfloors I've seen are usually 5" wide and are T&G. They're usually installed over beams/girders spaced 4' oc. If the boards are stiff with no deflection between the joists ( or whatever they're laid on ), then you're probably ok to install directly over them at 45 to 90 degrees. Usually solid planks that wide will have some cupping so they may need to be sanded flat first. My inclination would to just overlay with plywood.

Thanks Gary, this is a project on a tight budget, I feel comfortable installing over this tankish subfloor, it appears very flat.

Thanks for the explanations and photos! I have an OSB subfloor and we bought 3/4" solid brazilian cherry. I didn't see any manufacturer's instructions that came with the delivery of the solid flooring. Is it safe to say that it can be nailed directly onto the OSB subfloor?

Thanks.

Hi Gary,

What size staples should be used on the 1/2" CDX?

Before purchasing my flooring, I removed carpet in one room and discovered I have the 1" Redex tongue and groove sub-floor. I wanted to install 5/8" x 3-1/4" strand bamboo and nail it down, but based on everyone saying dont nail to particle board, I have settled on a floating 5/16" x 4" Schon Chocolate Shapelle from Lumber Liquidators. It is tongue & groove and glues together. I have since removed an older 3/8" engineered wood floor that was glued and nailed directly to the Redex in my foyer. Having discovered it nailed and glued directly to particle board got me wondering if that would be acceptable or did I just find someone else cutting corners? I would really prefer the 5/8" strand bamboo to the engineered product. I did read the article that recommends placing 1/2" plywood down as an underlayment for naildown applications, but am trying to keep from having to raise the floor that much. Also, what is the best way to remove the old troweled down adhesive in the foyer? Scraper, rent a sander, something else?
Any help would be much appreciated.

uh using particle board as sub floor is a very BAD idea. It swells waaay to easy and does not offer good grip with screw and or nails.

*edit* oops didn't notice the date haha

I wouldn't go with OSB. OSB isn't what you're supposed to use to nail down or even glue down. For whatever reason it doesn't want to stick that well. Plus if you have a claim you may get in trouble. Most houses these days are built with particle board. Sometimes if the particle board gets wet because the roof wasn't on in time before it rained, it'll cause problems with the install after it dries. Usually we take our 7" floor grinder or a belt sander and go over the floor to take and wood burrs off.

This is a great topic for a sticky thread. Now that it's 2012, are there better solutions? Having a weather resistant T&G panel is a great idea, but some feel they can't be glued to.

I'm using an initial 3/4" subfloor, then a rubber isolation mat, then two sheets of another yet-to-be-determined ply (likely two layes of 5/8" ply), then glue and cleat 3/4" T&G NA Black Cherry. The assembly is for soundproofing.

Given all these layers of ply I'd like to go as conservative on the cost as possible.