Plywood vs OSB

[Tom Godley]

Construction started on my addition this week - some demo work prior to concrete work next week.

They built an OSB wall to cover the big hole in my house -- I was surprised with the odor coming from the OSB. I noticed it, but it actually bothered one member of the family quite a bit - and it was only three sheets!

I can only assume it is the glue -- anyone have any experience with this?

I am quite happy with my contractor - They do a lot of work in my area. He told me when we were starting the process that they use OSB all the time and the up-charge to plywood is not worth the cost.

I did discuss the use of OSB on the roof and he did tell me that OSB is indicated to have less resistance to being out in the weather than exterior sheathing. Also some say nails do not hold as well - he did not feel that was the case. He indicated that they cover it and will begin to roof it within a few days - with 50 year roofs -- that will be the next guys problem.

But now with the odor I am rethinking this issue! Also, where does this stuff come from -- is it domestic or from Canada? .......... Or China :(

I think I better look!

[David G Baker]

I have not heard of allergy to OSB but there is always someone that has a low tolerance to things. Formaldehyde was used in particleboard and that caused a lot of problems for folks, me included, but I don't know of it being used in OSB. If it comes from China it could be anything.
I have a lot of OSB stacked in my pole barn and it does have a smell but I haven't found it to be irritating.
There are a lot of pole barns in Michigan that are lined with OSB and the smell seems to fade in a reasonable length of time. OSB seems to be the main choice to go under vinyl siding on new construction and almost exclusively as underlayment on roofs both new and re-roofing.

[Chris Padilla]

I dunno about OSB. My roofer wanted to used OSB sheathing and in the end, I went with plywood for one reason:

If the glue fails:

OSB has NO structural support
Plywood at least has its plys for support

[Mike Cutler]

Tom

Me personally, and I emphasize the personally part here strongly, would never allow OSB on my property. In my opinion, it's garbage. It's cheap,and that's why people use it. To be perfectly fair though. There are varying grades, type and qualities of OSB. All OSB is not the same. I still wouldn't use it though.
To be fair to all of out builder friends here on the board. Many times the customer doesn't want to spend the extra $$$ to use a better product, even when the builder points out the long term benefits of a different/better product, so the builder has no choice.
I've ripped out quite a bit of it over the years. It's a cheap exterior sheathing material that is being used in the wrong applications.
As for the odor problem. Do an internet search on FEMA trailers, and odor.

As for using it on roofs. I can almost guarantee you that I can drive through a newer construction development and after 5 years tell you which roofs have OSB as sheathing, or to more correct the improperly selected OSB for the application. It creates an obvious "washboard" effect on the roofs.

As for the "Upcharge" to go to ply. It's easy to predict, even using retail price structure at a Home Depot as a model.

It's your home. There is no difference in putting up the properly selected plywood sheating and substrate material. Only the material cost is increased. If you're willing to absorb the increased material cost for an alternative code approved material, I don't know why the builder would have a problem.

Apologies for the strong sentiment. I used to do some remodeling/renovation to supplement the "lack of income". I observed which products didn't stand the test of time,and OSB is one of them.

[Jason Koon]

I'm going to be making some rolling garage organizers from a woodsmith plan. It calls for 3/4" ply. I'm wondering how much weaker OSB is because I can make 4 OSB organizers for the cost of 1 plywood one. Birch is $42 / sheet. OSB is $11 / sheet.

[Bruce Haugen]

Jason, You'll find out how much weaker it is the first screw you put into it. IMNSHO, it is inappropriate for your application. It will delaminate the first opportunity it gets, and you'll have to build those suckers all over again.

Bruce

[Joe Chritz]

OSB is great for what it designed for. Structural sheeting. Many hundreds of thousands of sheets are used for sub floors and roof sheathing. I don't personally know of any failures do to the type of substrate used. If enough water gets in to damage osb it will kill CDX plywood as well. OSB is generally rated for temporary exterior use, meaning it can be left out during construction without damaging the material to an appreciable degree.

Don't worry about the smell, it is probably just newly produced. When I had a pallet delivered for roof sheathing on my house the interior sections were still warm to the touch.

I wouldn't use it in place of plywood for any cabinet type projects except maybe in place of shelving where it is properly supported. It has to be secured according to recommendations to have the strength needed.

Joe

[Bryan Rocker]

While I do agree that OSB is cheaper than plywood and it is not as structurally sound as plywood the washboard effect usually has its roots in other problems. Some of these problems include not using clips to between the trusses, 2' on center trusses can also be a contributor. I have used a ton of OSB on roofs and decking in HFH houses. We have house #23 and 24 getting ready to close in the next month or two. You do not see the washer board look on our older houses. I personally won't use OSB on my house nor in the shop that I hope to start this summer :)

[Brian Effinger]

I have to agree with Mike and Chris on this one - plywood is far superior to OSB, especially on a roof. As an architect, I always specify plywood on my drawings because I feel that it is stronger, especially in shear (shearing comes into play with lateral loading - i.e. wind). Sometimes a customer will ask for OSB to save money, but I try to dissuade them from it. If they are insistant, I'll allow it on walls, but I try to keep it off of roofs and floors, unless they go with much thicker panels - like 3/4" or 1". On floors you could have significant point loads, and on roofs, the weight of the snow is too much for OSB IMHO. I also feel that plywood is supperior when it comes to nail pull-out. If a properly sized good ring-shanked nail is used, a piece of plywood will never come loose.

I'm sorry I didn't answer your actual question about the smell, but as an architect, I just had to add my general opinions on OSB, before the project is started. I'd also take a good long hard look at this contractor, get references and visit those references. I'd also ask around and get some references on their work from other people that aren't affiliated with that particular contractor. That way you could get an untainted view of them (the references they supply undoubtedly got a break on the cost of their project for allowing the reference). Your local building department is a good place to visit and ask questions too. Also, just because a contractor does a lot of work around you, doesn't mean they are good. Case in point - there is a well advertised contractor in the Buffalo & Rochester area that claims to be the best and the most "green" contractor, but I have personally seen their work on a project I designed, & WOW what lousy work (I say lousy, because I'm sure there are profanity filters here, but this contractor's work makes me profane). They basically ignored my drawings and built whatever they felt like, and then they bad mouthed me. Sorry, now I am starting to rant, so I'll stop. My point is, be carefull with contractors, and do a lot of research on them so you can pick the best one.

[Brian Effinger]

While I do agree that OSB is cheaper than plywood and it is not as structurally sound as plywood the washboard effect usually has its roots in other problems. Some of these problems include not using clips to between the trusses, 2' on center trusses can also be a contributor.

That is true that there are other problems which create some of these effects, but I see the two as being interconnected. I too often see contractors choose OSB because it is fast, cheap and easy, and this carries through to all aspects of their work - including not using the appropriate hardware and joist/rafter/truss spacing. If the contractor used all of the manufacturer specified hardware, specified support member spacing and proper thickness, then OSB can work in some instances, but this carefull attention is so often not the case.

[Alex Shanku]

Many hundreds of thousands of sheets are used for sub floors and roof sheathing.

Using OSB for a subfloor is a terrible idea. For sheathing and roofs, maybe, but subfloor?!?!

[Peter Quadarella]

Whoever built my shed out back used OSB for the floor. I put my foot through the floor last week when I was going in there and now I have to replace it. I'll be doing that with plywood.

[Jason Koon]

so is there a better option above OSB? is CDX as strong as a birch plywood? These things are getting painted and shoved in a corner.. I'm not concerned about looks, just workability and longevity.

Thanks,
Jason

[Chris Yarish]

Using OSB for a subfloor is a terrible idea. For sheathing and roofs, maybe, but subfloor?!?!

In my limited framing experience, I don't know of any other subfloor material used in my area. OSB is like the industry standard here...in fact I have never seen anything else used.

[glenn bradley]

I'm going to be making some rolling garage organizers from a woodsmith plan. It calls for 3/4" ply. I'm wondering how much weaker OSB is because I can make 4 OSB organizers for the cost of 1 plywood one. Birch is $42 / sheet. OSB is $11 / sheet.

Could be a reason . . . I have OSB as part of my shop walls and have no problem with it. I would not use it for "cut to shape" structural items though. As a sheeting, tacked down "every so far between" it works fine.

[Wes Bischel]

I used OSB on my garage 15 years ago. It has performed well so far on both walls and roof. I will say - if I were to do it again, I would use it for the walls, but use ply on the roof. I don't have the washboarding effect, but I didn't like how "bouncy" it was while working up there. It deflected more than I would have liked. Just a thought.

On the formaldehyde issue, some people are much more sensitive to it. Depending on the concentration of the off gassing, my eyes will burn and I will notice tightness in my chest. I could not go into an industry mobile home show due to the high concentrations.

FWIW,

Wes

[kevin mcgril]

Hi there,

I'm one of those folks with chem sensitivities and OSB bothers me (respiratory symptoms). I built a shed 4-5 years ago and when it heats up in the summer it still smells extremely strong.

If outgassing is a concern, look at exterior grade plywood because it uses phenyl formaldehyde as part of the adhesive which does not react to water like urea formaldehyde does which is in normal plywood. Water mostly being humidity experienced in a normal structure. Do some googles if you're interested, outgassing, interior vs. exterior plywood.

-Kevin

[Mike Cutler]

Using OSB for a subfloor is a terrible idea. For sheathing and roofs, maybe, but subfloor?!?!

Alex

Unfortunately this is where some of the confusion about OSB comes from.
Subflooring has to adhere to a structural standard. There are many "engineered subfloor products" that are by definition "OSB". But, they are a much different "OSB" than the exterior sheathing product, and the difference will be reflected dramatically in the price. There won't be any realized savings.
Georgia Pacific, for example, makes a wide variety of engineered subfloor products that are dimensionally more stable than plywood, that are rated for subfloors.

[Matt Ocel]

I would use osb over plywood in for homebuilding in every application. For instance.
When I was a job sup at D.R. Horton we would install 3/4" t&g osb for sub floor as standard building practice, However, If a finished "wood floor" was to be installed, we would then install 3/4" t&g cdx plywood for sub floor. So we would have sheets of osb and sheets of cdx installed on the same cap. OSB allways out performed the CDX. CDX would start delaminating if there was excessive dew in the evening. As for roof sheathing, I don't care what you are using, when there is a little frost in the morning and the sun hits it just right you can count the pieces of material used telegraphing through the shingles.
As for the odor, I beleive the last product using formeldihyde(not the right spelling) in any product in new construction was treated lumber.
Most osb is made in the US and Canada. If you have any questions on osb you can go on the APA (American Plywood Association)website.
Also osb is a man made comodity, the price can be volatile, at times osb can be more expensive than plywood.

[John Gornall]

I reroofed both my houses 3 years ago. Took off shakes, put on OSB, installed a 45 year fiberglass shingle. When I had to decide between plywood and OSB I found some interesting studies done by the engineering department of a local college where OSB was considered superior in all tests. Plywood came apart in the wind tunnel in areas with voids in the inner plies. Of course you have to use the correct standard OSB. My reading also led me to installing the OSB with staples instead of nails. The staples I used have an adhesive that actuates somehow when driven by an air gun into wood. I tried my darndest and was unable to pull these staples out - can't be done. My houses are by the sea and get battered by southeasters all winter up to 60 plus knots - all is well.

I did the walls in my shop in 1/2 inch OSB. Attached with screws, I can remove a panel and run wire or air anytime, or screw anything to the wall. Painted it all with 2 coats of latex paint and the OSB smell was gone in about a month.

[Alex Shanku]

Alex

Unfortunately this is where some of the confusion about OSB comes from.
Subflooring has to adhere to a structural standard. There are many "engineered subfloor products" that are by definition "OSB". But, they are a much different "OSB" than the exterior sheathing product, and the difference will be reflected dramatically in the price. There won't be any realized savings.
Georgia Pacific, for example, makes a wide variety of engineered subfloor products that are dimensionally more stable than plywood, that are rated for subfloors.

Right, I have never heard anyone call Advantech, "OSB".

[Karl Brogger]

I preffer plywood. One of the reasons I bought the house I did is that the walls and roof were sheated with ply, which is really uncommon around here.. I could live with OSB. But never, ever build rite. Its cardboard. Sure, it doesn't rot, but I'd almost guess the sheatrock has more structural integrity than build rite.

[Matt Ocel]

As with the very first stucture built on this earth man has been trying to find a better and more cost effective path.
One of those paths is to use osb over plywood.
Building materials are constantly evolving. osb is a much better product than it was 10 years ago, and to compare osb vs plywood is almost as close to comparing an apple to an apple.
OK, if I am wrong on the osb vs plywood arguement, why are there thousands of homes built with osb that are performing at or above expectations? NOBODY can walk into a finished home and say "Oh this home has to have been built with OSB" or "plywood".
OK, You still don't see my point.
Let me try this-
Why would you use When you could use
SPF floor joist vs LVL's, I joist, trusses
SPF studs vs parralam or LVL studs
Drywall vs Lath and plaster
Carpet vs Terrazzo, stone etc.
Vinyl siding vs Brick, Stone etc
Laminate counter tops vs Granite, Concrete, etc
Gun nails vs #16 cc
Vinyl windows vs Aluminum Clad, wood interior
Roof louvers vs Ridge venting
Asphalt Driveway vs Concrete, Concrete pavers
Cedar, Treated decking vs Brazillion Teak
Fiber glass insulation vs Spray foam ureathane
Composit roof shingle vs Tile, metal

Everything on the left is accepted and has proven the test of time.
Everything on the Right is accepted and has proven the test time.

Now tell me how important you think the osb vs plywood arguement is?

[Jim Becker]

Well, I know my contractor wouldn't agree with your contractor about the worth of moving to plywood from OSB! Michael only uses plywood. No OSB on his jobs. LOL

As to the issue you raise, I suspect there is something funky with the particular material they used. My experience with OSB in my shop offered no unusual odor. It sounds like the glue is off-gassing in some unfortunate way.

[Jack Porter]

I agree with Brian, try to avoid using OSB on roofs but on walls it is typcially not an issue with conventional residential construction. Also, if you are going to try to use OSB on roofs make sure to check the span rating and APA stamp ,and if using it for walls and roofs make sure to check allowable diaphragm loads if your structure is lacking shear walls. Pullout values of fasteners in OSB are significantly lower when compared to plywood. Plywood will creep less than OSB under sustained loads, has been known to hold up better to the elemetns (however some of the newer glues are very resistant to weather/water), and plywood will resist impact loads better than OSB (if a tree limb or any falling/flying object impact the structure).

[Rob Will]

Watch out for the BORG :eek: !!!
Around here, they sell a cheaper grade of plywood and OSB than do regular lumber yards.

I think 3/4" T&G OSB is fine for a roof deck or a sub floor but like any other building material, keep it dry.

Rob

[John Russell]

I recently was faced with a decision about using OSB or plywood for sheathing/sheeting and outbuilding. This information helped http://www.sbebuilders.com/framing/plywood-osb.php

[Peter Quinn]

I'm not a roofer but a good friend of mine is. He is a CDX man, wont't touch a job here in the North East speced with osb. He recently subed for a guy on a re-roof and was telling me they used a georgia pacific product that was an OSB type material with a synthetic 30# felt impregnated (made specifically for roofs, cost MORE than CDX) that was a brieze to install. 50 year archt. comp. shingles laid right on the board, held nails and screws well, he was impressed. Of course you'll have to wait 30 years for the real results.

Most of the builders I know around hear will tell you find a guy using OSB for roof decks, and you have a guy who is probably living in his pickup and changing addresses a lot too.

I'm guessing the off gas issue is less of a problem with new construction where the stuff can vent for weeks as the house is built. For additions and remodels where the space is dried in quick and the stuff then vents into insulated living space maybe plywood is a better choice.

Another problem I've seen in the osb vrs plywood argument is in rainy climates, get osb or cdx floor deck wet, the edges swell, but when dried in the plywood mostly shrinks back to its original state, the osb stays swollen and has to be BELT SANDED flush or it telegraphs to the finished floor. Not a pleasant job.

[Rick Lizek]

http://huberwood.com/main.aspx?pagename=productoverview
Advantek is big around here. One contractor had a skeptical customer so he did the old water bucket test. A strip of ply and a strip of advantek in a bucket for a week Plywood fell apart and the advantek was still good.

[Karl Brogger]

Another problem I've seen in the osb vrs plywood argument is in rainy climates, get osb or cdx floor deck wet, the edges swell, but when dried in the plywood mostly shrinks back to its original state

A "good" builder will spray down the sub-floor with a finish when they get the basement capped, Thompson's water seal something of that nature, to protect it before the house is sealed up and protected from the elements. It actually helps with clean up down the road as well. It's alot easier to take care of sheat rock dust when it doesn't get ground into the sheeting.

[Peter Quadarella]

I was confused by Matt's post above. On the left was a list of cheaper, less durable, or uglier materials, and on the right was a list of more expensive, more durable, or nicer looking products. If OSB belongs on the left and plywood on the right, I guess I agree?

[Matt Ocel]

Peter - Yes, you are correct. That is the point I wanted to make.
There are also products that could go on both sides. Such as cpvc water lines. They are less expensive, easy to work, and perform great.
(next time I will format on excel and download)