Replies

1. 
   Ian.D.Gilham. | May 07, 2001 08:40pm | #1

   *
   It is used as standard sub-floor in Oz, plywood is rarely used.
   A bead of construction adhesive is run on the top of each bearer and the OSB nailed down.
   The only problems occur if it has water standing on it for any length of time -- the edges tend to swell and it will sag slightly between the bearers.
   I've laid both parquet and strip-flooring over it consistently with no problems.

1. 
   George_Abramshe | May 07, 2001 11:58pm | #2

   *I agree with Ian. As long as it hasn't swelled or delaminated from standing water, is glued and nailed properly to the floor joists, I've never had any problems with laying strip and plank flooring.

1. 
   david_thodal | May 08, 2001 05:54am | #3

   *Iza, I will have to disagree with george and Ian there on using OSB for subfloor under strip flooring. I would never do it.First, OSB has a tendency to absorb moisture and swell. Even when kept dry from the weather, it can absorb moisture from the air. The swelling once begins will never diminish. I think it was last October issue of JLC that had an article on this issue.Second, OSB does not hold nails or screws very well. Driving your flooring nails through the toungue into the OSB causes fracturing of the woodchips and glue. Any upward or even lateral movement can rip the OSB apart at the nail. I have no qualms about nailing a hardwood floor into 3/4 cdx plywood and holding over time. I cannot say the same about OSB. Third, to be honest I hate the stuff. Environmentally it is a bane, not only to forest health and managment, but also for energy consumption in production, waste toxicity in production and the developing trend in eliminating employment through increased mechanization in the entire cycle. Finally, I avoid using OSB anywhere, but especially under a wood floor.walk gooddavid

1. 
   Ron_Rosa | May 09, 2001 01:42am | #4

   *I am with David on this one. Oak flooring is to much money to throw OSB under it.

1. 
   davidmason | May 09, 2001 07:08am | #5

   *OSB is standard practice here under all kinds of flooring. Dave

2. 
   BrianW | May 09, 2001 11:41am | #6

   *You might want to try Advantech, which is an OSB subfloor made by Huber. It is made with a much higher resin content than regular OSB. It will not swell and installs very well. I am a builder in central North Carolina and use it for everything I do.

3. 
   Greg_Warren | May 09, 2001 02:59pm | #7

   *Although I have it under an upstairs floor in a production home I live in and I have no problems with the Maple strip floor nailed to it, my next home, a custom, will have plywood under it by my choice. David makes the point of the possibility of the inability of the nails to hold over time. I am not ready to take that shot. The product does not have enough history yet.

4. 
   Fallingwater_ | May 21, 2001 11:50pm | #8

   *To spend the $ on the oak flooring, and then use OSB as a subfloor, seems like a mistake. I must admit, I am against OSB in general, but particularly in your case.

5. 
   Herschel_Brichto | May 26, 2001 10:36pm | #9

   *The only good use for OSB is to throw down as protection over floors that will be refinished after.Here's a thought experiment nail a sheet of cdx using one nail in two corners of the short side to a wall do the same with OSB , next grab the bottom of the sheet with your hands and rip it away from the wall, the plywood will come off with the nails, the OSB will come off way easier,with the nails still in the wall.

6. 
   Mike_Smith | May 27, 2001 01:56am | #10

   *i've built with 3/4 T&G fir plywood since 1975..exclusively...until this year... now i'll use Advantech by Huber ..i think it is a superior product to 3/4 fir ply.. and .. i think it's nail holding ability is just fine for oak floors..it is also superior in ability to weather a lot of rain & snow...use it once on a small project.. bet you won't go back to ply..b but hey, whadda i no ?

7. 
   Tommy_B. | May 27, 2001 02:44am | #11

   *I think most converts to the Advantech are doing so because of the inferior quality of t&g fir. Over the last decade, the incidence of delamination in plywood with even a small amount of moisture has made the case for the advantech.I believe that properly manufactured plywood is superior to osb-type products, it just isn't around anymore. There is a top shelf plywood product for subfloors but my suppliers aren't carrying it.Then again, at some level it comes down to price for most customers and although the advantech is competitive here, I'm sure the premium ply would be a few bucks more a sheet.The advantech is heavy, but installing it is a breeze of a job even for one man. Sledge not required.Tom

8. 
   Boss_Hog | May 27, 2001 10:37pm | #12

   *I don't quite get what you mean by " Environmentally it is a bane".My understanding was that OSB could be made from almost any size of tree, or maybe even cut-offs from larger logs. Plywood requires larger, straight trees with relatively few knots or defects. Could ya explain yerself a bit more ???

9. 
   david_thodal | May 28, 2001 05:57am | #13

   *Ron, There are several considerations in my statement regarding OSB as an environmental bane. Irregardless of where the chips come from, the manufacturing process uses chemicals that are extremely toxic. There has been numerous violations in this country of air and water waste discharges of these chemicals. Plywood uses other chemicals in the glues that are toxic but not to the degree of OSB. Further more the quantitys of glues and the process used in the production of OSB generate a greater toxicity factor than that for plywood. Finally the production of OSB requires considerably more energy input than plywood.On some level, the idea of using chips generated by the waste from a saw mill operation and producing a useable building product sounds "green" Even if we consider the loss of biomass to the forest from removing the trees, the trees were removed for other purposes, i.e. lumber production. It is not cost effective to return the chips to the forest floor. Selective cutting of logs eliminates this concern for loss greatly, but would not generate enough chips to be viable for "chip board" production. Using this waste for chips presents problems in quality control as a higher percentage of the chips would contain lower quality wood and more bark. To make OSB and for that matter any of the engineered wood products using "chipboard" material, a consistant large volume of raw chips are needed to ensure profitability at these plants. To achieve these goals the only solution is clearcutting. In Manitoba and Colorado are two plants that rely heavily on aspen to manufacture OSB. There are probably others as well. The trees in these areas are being decimated by the production and the resulting loss of habitat is critical.In the South, where there are private plantations and a good growing season, they are basically creating a monoculture forest on continual rotation to generate the chips. This often includes the heavy use of herbicides and fertilizers to promote growth. Not to mention again, the loss of critical habitat that results when harvesting takes place.On a final note, a consideration must be given to the increasingly mechanized production from planting, through harvesting and production which has the direct affect with people losing jobs. This was the real reason some many woodworkers lost their jobs in the Pacific Northwest; it was not the lack of timber availability, it was that many mills improved their technology thus eliminating the need for manual labour.I use plywood because I think it is better environmentally than OSB. I use plywood because in my experience, it is a superior product to OSB. Economics and availabilty aside, I would choose board sheathing, pine fir or hemlock. However we have effectively reduced our ability to sustainably produce our lumber needs for several generations with are past timber practices and our current building greed.I hope this diatribe is of use.walk gooddavid

10. 
    Bob_Walker | May 28, 2001 12:45pm | #14

    *David:"I hope this diatribe is of use."FWIW, your message struck me as a well expressed statement of oft-times overlooked factors.To me, a diatribe is a rant or rave without the thought or consideration of your message.

11. 
    Mike_Smith | May 28, 2001 07:55pm | #15

    *david.... good for you...if tilting at windmills is your bag.... personally.. i don't buy it....if the ply mills need a better grade of lumber for their veneer, then they are either leaving the trash trees .. or the trash trees are going to a different mill..me .. i expect to be building with composite treated stock for ground contact...engineered joists... advantech subfloor advantech type wall and roof sheathing and engineered studs...when i started... the only thing i would use was doug .fir framing and fir ply...C-select pine was the standard trim...times change and so do the products we have available...Cuprinol green #10 was the closest we could get to protection for sills.. and deckframing was figured for a ten year life..this is better...and more envionmentally sound than it was in the '60's...we can actually design and spec construction that our customers can maintain.....the volume of construction that takes place just in the US cannot be supported by plywood... so the average builder can vote for better products with his checkbook.... i'm voting for engineered wood products...europe voted for a masonry based construction because they didn't have the wood products to support their needs..just look at the K-D products that have been dumped on us... pure junk.. almost impossible to cull.. almost impossible to predict which ones are ging to curl and warp...nope .... the forest products industry is going to have to develop better products... not grow them.. and cutting our best timber for 6-ply veneer plywood doesn't seem like the ideal to pursue...b but hey, whadda i no ?

12. 
    Jim_Ryan | May 28, 2001 11:09pm | #16

    *I agree with David, I am a professional carpet installer, and these floors are not reliable when it comes to holding the tackstrip in place if the carpet is properly installed. Jim Ryan

13. 
    Mike_Smith | May 29, 2001 12:32am | #17

    *jim... IMHO....bs.... i think you are tarring all non-plywood floor / sub-floor with the same brush..i'll bet the ones the failed on you were particle board...or chipboard..i'll bet they weren't OSB.. and i'll bet you a beer in the tavern that they weren't advantech....b but hey, whadda i no ?

14. 
    david_thodal | May 29, 2001 06:13am | #18

    *Mike, Funny thing I thought the same "tilting at windmills" until I stopped to think. These concerns are not imaginary nor are they dillusionary. They are real with plenty of hard evidence to support them. Respectfully, you are seeing windmills and perhaps a grand pastoral scene to go along with them, rather than confront a very real issue.Name a species of tree that is a trash tree and explain why? I think time will bear me out, but I do not expect to see engineered wood product houses last more than 75 years if we are lucky. There are too many known factors and who knows how many unknown ones that will lead to eventual breakdown.I will agree with you on the fact that lumber can be bad and seems to be getting worse. We have basicly destroyed a sustainable timber base through over cutting and are now trying to feed our insatiable appetite for wood with immature trees dryed too fast. And expecting the forest product industry to develope better products... one must examine the entire life cycle of the product, manufacturing, use and reduction and decay. I do not think anything will come close to wood for total benefit vs harmful sides.It will take several generations to bring our forests back to optimum health and thereby use. Some areas will be quicker than others. In the meanwhile there are a number of things we can do. For starters we can stop building such wastefully large homes, regardless of materials used. We can think of recycling lumber from existing structures no longer livable. We can promote better stewardship of our woodlands, both national and private, managing for sustainable production rather than a quick buck for the stockholders. We can utilize existing low impact products such as strawbale, adobe, rammed earth and masonry cordwood construction to name a few, where best suited. When I was building in Maine, we used alot of Eastern hemlock to frame and sheath. A good wood and similar to doug fir in strength. Especially timber frames. We used oak, air dryed for mud sills, locally available and very good rot resistance. Pine was the trim, inside and out. Eastern white cedar for shingles or pine clapboards. And for some unknown reason, used 5/4 spruce for decks. Times change as do products, but not neccessarily for the better. I never stated we should cut the best trees for 6-ply plywood. I said I use plywood over OSB, however I still prefer board sheathing. I think when all things considered, that is still the best choice for wood frame construction. nice chatting with youtwo books for you, both by Richard Manning... LAST STAND Logging,Journalism and the case for Humility and A GOOD HOUSEwalk gooddavid

15. 
    Mike_Smith | May 29, 2001 01:58pm | #19

    *david.. all the things you said are true.. the windmills are the scope of the building industry.. the solutions and techniques you described worked in the middle of the woods in maine...on an extremely small scale...they don't do anything for a builder in tucson..as to building smaller houses.... economics will decide that.. not the nahb.. not david.. and not green legislation...... you are projecting your desires on a population that isn't listening .. nor do they have any reason to listen..if woood won't do it.. houses will be built with something else..cheese maybe ...or concrete....or whatever works...my guess.. engineered wood products will still beat steel and concrete for the mass market to house our citizens...

16. 
    david_thodal | May 29, 2001 02:17pm | #20

    *you are right mike.unfortunately we tend to proceed without thought to consequence until it is too late.buildingenergy consumptionagriculturewe will continue to proceed in use whatever we want regardless of the consequences for the future.i may not be tilting at windmills, but i know i am probably beating my head againts a wallwalk gooddavid

2. 
   iza_ | May 29, 2001 02:17pm | #21

   *
   Any problem using 3/4 inch T&G OSB subfloor instead of plywood? Is it less durable, stable etc? It will go underneath strip oak flooring that will be nailed to it and wall to wall carpet in other areas.