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I plan on building a new house in about a month. All of the building materials estimates list OSB for the subfloor. My father in-law seems to think plywood is the only way to go. The difference in price would be about $400 for the entire house. What are the benefits of plywood over OSB. My father in-law thinks OSB will swell and break apart if it gets wet, but plywood is more resistant to water damage. Is this true? We plan on installing some solid hardwood flooring, some ceramic tile, some vinyl, and some carpeting. Does the subfloor under each of these materials matter? (we will also use concrete board under the ceramic).
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Plywood. Water resistance & solidity. Others will disagree, but i love the 5/8" Sturdi-floor (an APA marketing term) I put down 16" OC in the kitchen. Especially after I laminated a second 5/8" layer (had some extra)! We had the room-shakes-as-you-walk-by problem (my wife complained it made her feel elephantine), plus the floor was curved -- all the appliances looked like they were perched on a hillside, leaning left. I planed and reinforced the joists.
Below hardwood, this should not be so critical. Rooms with sturdy flooring & no water -- OSB should be fine? Just hope for dry weather during the framing. How exciting to be starting a new house! For me, it would just be too many choices... I like the trapped feeling you get from remodeling.
*In the early days of OSB production the glue (resin) used to hold the matrix together was urea-formaldyhyde based. The properties of this resin were such that it was not very resisant to moisture and OSB of this era would swell like a sponge.Now and for the past 8 years of so the bonding resin has a polymer base. The properties of this resin make the end product much more resistant to moisture. I have left samples out in the snow (in the name of science) all winter and in the spring they are swollen about a fat 1/16". The plywood in the same test zone (scap pile actually) is in about the same shape. If you allow alot of moisture to come in contact with almost any wood it will cause problems in the long run. Using OSB for a subfloor in the 3/4 T&G or the 1 1/8" T&G should be as good as plywood apples to apples. If you are going to save $400 spending it on something other than plywood would be my suggestion. Like maybe a better plumber--
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I totally agree with you..We built two homes in the same general area last summer and both got hit by some very heavy rain before the roofs were on. One had 3/4" OSB and one had 3/4" SYP plywood. We had to cut out three sheets of plywood because of swelling and surface layer delamination. The OSB was not damaged at all by the water.
Either one is going to take a beating from prolonged exposure to water, but I certainly wouldn't say plywood was more resistant to water than the OSB you can buy today. It is also interesting to compare brands of OSB if more than one is available. You will notice that different species of wood are often used by different companies , depending on their manufacturing location. Some have a noticeable difference in the amount of resin that lays on the surface. This has a lot to do with their water resistance qualities.
I like OSB and have much better luck with it than I have with the junky SYP plywood available to us.
*I will have to agree too. I am a framing contractor from Ohio, as you may know we see alot of changes in our weather. Every time OSB has withstood the abuse of the weather. I beleive in it so much that last year when I built my own house, you guessed it, I used OSB from the floors to the roof. My advice as a contractor and a son-in-law is: DO NOT listen to the father-in-law!Have Fun!
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OSB, OSB, OSB.........
My lumber salesman handles dozens of 'warrantee' issues regarding structural panels each year. Every one is a problem with plywood; never OSB.
I'd pay $400 more to sheathe my own home with OSB rather than plywood!
More plywood plants go off-line each year and more OSB plants come on-line.
I'm glad to see so many posts in favor of OSB. 2 years ago I'd have been ridiculed here for siding with OSB rather than plywood.
I do recommend using 3/4" t&g sturd-i-floor rather than 5/8" if available. We have both and at .75 a sheet more it feels better.
*I, too, use OSB when I can. Some homeowners will not allow it and are willing to pay a premium for plywood (which I believe is an inferior product). We have some local builders who really badmouth OSB and part of their sales pitch is "We never use waferboard in our houses!". Nothing really takes a lot of water and stays unaffected, but 3/4" T&G OSB holds up better than the plywood we have been getting lately. What's up with that anyway? An unacceptable percentage of panels are delaminated when they are delivered to the job site, and even more delaminate after installation. Reminds me of the "Blows" the lumber yards used to sell at half price!!
*OSB without a doubt. 4 years ago we used plywood on all houses.Needless to say they got wet.By the time we had the house dried in, the plywood was so delaminated and sagging between floor trusses,it would take 1/2 day to cut out the bad spots and replace with new.Now this looks real good to the customer when he/she sees 4x4 pieces of subfloor looking like it was built with scrap pieces.Thankfully we screwed it all down,but nonetheless that adhesive really holds.Now, I will not use anything but 3/4 t&g osb.After a few soakings,the edges do tend to swell a little.What I do is hit all the edges with a belt sander to level all up.Have never had a problem with it falling apart or sagging between floor trusses.William,your father-in-law may have this vision of blandex in his mind.This stuff was the old kind that did tend to fall apart when exposed to the elements.There are different brands,look to see if what the builder is using has the edges painted with a sealer & also we use the kind that has slots cot in the tongue for drainage of water so that it doesn't set there until it has to soaked through. I also use OSB exclusively(roof,walls,floor)without any problems.
*William, I think the others have said enough about the osb issue, but I noticed that you mentioned cement board! Oh Oh!I'd highly recommend a "dry pack" concrete base instead of the wonderboard products, especially on the floor.Re-grouting is a pain in the knees!Blue
*Wow! Time to reconsider OSB!Do y'all use it for roofs too? Most builders around here sheath with OSB, but use ply for the roof.
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Yet another vote for OSB. However, I decided I wanted an even stouter sub floor, so I went with a 7/8" T&G OSB. I do plan on covering the kitchen, entry and baths with ceramic tile, and have selected J.Hardies underlayment (cement fiberboard) as the backer in these areas. I have used and researched the various cement products out there, and I like this the best for setting the screw heads and obtaining the smoothest sub for the tile.
Also, the OSB did tend to get wet during the summer with rain water, even with my best tarping (we get strong glacial winds). Our climate is merri-time (south central Alaska) and as such we have quite a few inclement breaks through the season. After we finished drying in the house, I cranked up the furnace (insulated and vapor barrier first) and allowed the house to completly "dry" out prior to applying drywall. (Thank you, Mr. Ferguson (FHB contributor) for the tip - this was my first shot on my own, and it worked well.
I also used 7/16" OSB for the roof sheathing and the exterior walls as well as any shear walls. It has held up great throughout the process. All the roofing projects I've observed here in the past few years have used OSB. Use the H clips for stability.
Final note: the 7/8" floor is glass smooth, and still perfectly level, (could be the OSB used in the TJI's??) even after studs (int. 2x4's) tended to warp, some so dramatically, that I considered replacing them. With that in mind, I'm taking a stronger look at Truss Joists "new" engineered 2x's. Especially for kitchen and baths, offices, etc. Stick with a quality OSB.
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I've used and read much on OSB and have no reason to doubt it's a superior product. I'm shocked that on this puckered at both ends, lets overbuild the dog house group that OSB got great reviews.
As to blue's comments on cement board, I'll put a properly installed cement board floor against anything you want.
I first go through and screw the existing sub floor down(squeeks or not). I also sink all nails that stand proud. I then set cement board into thin set and screw it down. Then I set tile in thin set. No cracks or grout problems.
*Regarding the post a few weeks back about OSB for roof sheathing, several respondants posted they had problems with the edges of the OSB swelling, thus telegraphing through the shingles. Have others experienced this?I've seen delamination in SYP ply, but have never had a problem with fir ply.
*I've seen houses in our sub telegraphing the swelled edges. It turns out that the other contractors didn't like the idea of spacing the sheets on the vertical joints. The young stud complained to me "the rep want us to space each sheet at least 1/8"! That means we'll have to run a saw cut every 7 or 8 sheets!"I guess that was too much trouble for him, and he'd rather let the builder strip the shingles and cut it for him!Space the OSB, or be prepared for buckling!Blue, spaced out in MI"We have enough youth, how about a fountain of Smart?"
*Blue, I've gotta say, every quote brings a grin to my face...keep it up!In your experience, then, the boards do swell but evenly across the face...it's just a matter of giving them space to roam so they don't mushroom. I may have misinterpreted the old thread. I thought they believed that the edges wicked in moisture and actually expanded in thickness just at the edge, thus the line under the shingles.
*The "Sturdi-floor" rating can also be applied to osb.
*Gee, My first tendency is to vote for Plywood but I know from using osb that it really does hold up quite well in the weather and plywood oddly enough will delaminate rather easily in the rain.All this said, I would still find it hard not to pay the extra 400 and go plywood anyhow inside my house. I do know that it is a whole lot easier to whack my hammer straight trough a piece of OSB than it is plywood so from a strength standpoint I suppose I would prefer Plywood afterall.Confoundedly convinced,Pete Draganic(Another Ohio Contractor)
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I'm also facscinated to see so much support for OSB here! I'll be building a small lake cottage shortly and very interested in this topic - I was once told that OSB won't hold nails (or staples) as well as plywood. Is there truth to that? TIA
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Actually because a nail or staple is apt to go through more of the strands that make up OSB during pentetration than the veneers in plywood a fastener stands a better chance in the OSB. However unless you have at least 1 1/2" of either product for a nail base then it is not going to be dependable. That is why you take the time to locate the studs to nail your siding to and people are finding out that nailed siding in SIP construction is delaminating because most of those systems do not have studs.
However both products will hold a screw quite well or a roof barb if you have to fasten in the field such as in roofing applications. I also suscribe to the wood movement theory that means that any type of siding that will move seasonally or with temperature swings will be harder on the fastener and thus its base. That is also true for metal roofing which should only be fastened with screws.
*OSBers,My uses;Walls...OSb, 7/16" or "quality" ply 1/2"Roofs...b No OSBQuality ply w/ clips, 1/2"...16"oc...5/8"...24"ocSubfloors...quality ply 3/4" t&gI will use quality "inner seal" OSB if it's priced right, is available in my market (didn't used to be, need to re-check) and shows signs of having a long warranty of use (50-100yrs is good to me)By the by....I received a few junk shipments of ply in my time and luckily someone noticed all before being used, and in all the rain and snow soaked years of using 3/4" t&g I have had to do ten minutes of fix-up total, including drilling 1" drain holes to rid the water. Also walking on unclipped 1/2" osb 24"oc is one of the less fun things I do.From the contents of this discussion I will be looking over "improved" OSB again.b Always going across the grain,Jack : )
*I agree, Pete.Use only 3/4" douglas fir plywood for this job.I think strength of the material is better found in the ply.Hope this helps.
*Yup, On the roofs. I like 5/8" for trusses at 24 oc. 7/16 OK for 16oc. On a few houses I used 3/4 t&g before 5/8 was stock locally.Heavy but performs fantastic.
*Pete,I've been beating on some 5/8 OSB all day with my 24oz framer and can't punch through it with less than 7 whacks. I can get through fir in 4. Guess my lumberyard's buyer knows his OSB mills.
*Dave,It is true and one of the few advantages ply has over OSB. Of course the only time I run into tie issue is when nailing siding and flooring. In both cases I use ring shank nails and have never had a problem. Started using waferboard and aspenite (precursors of OSB) in 1984. No floor signifigant squeeks or siding blow-offs yet.It took me until 1992 to prefer OSB.
*I spent some time framing in Southern Maryland, about a mile or so from the Chesapeake Bay. As you might imagine, rain could have been a problem for the subfloors, which were always OSB. Our solution was after using plenty of construction adhesive and ring-shanks to put the deck down, we would use a garden sprayer to apply a liberal dose of Thompson's water seal. I always wondered if the Thompson's could have had any undesirable effects on anything. Never noticed any. I can say for sure, however, that we never did have any water problems with the OSB, despite the frog-strangling rains followed by days of 95%RH at 95 degrees.
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Pete- I used 3/4" TandG ply. for my subfloor and it was exposed to two Montana winters with lots of moisture and freeze thaw cycles. It never complained and was sound enough to use as a base for hard wood flooring. Bruce hardwood floor co. recommends either 5/8" or 3/4" ply. exterior grade or OSB-PS2-92. For more info. from Bruce call 1 800 535-0424 Ext.2600 -- that's their technical service dept.. John Fuhrman
*I like a product called COMPLY. It's kind of a cross between plywood and OSB, having two plies of a type of particle board sandwiched between three plies of wood. I have had excellent results with it in the wet Northern California winters. A side benefit is that it is stiffer than either OSB or plywood and makes for a more solid feeling floor compared to an OSB or plywood floor with the same joist spacing. I'll be using it on my own new home this year. Check it out!As with any other sheet product, be sure to follow the recommended spacing during installation.Anyone else have any experience with COMPLY?
*Some people like makita tools, some wont touch em. Some hate chevys, I even know someone who hates pizza. But for every product out there we can find the pros and cons.( we have a chevy and a makita and both work)I will use OSB for sidewalls at owner request. I will not use it on a roof, I have never used it on a floor. Why? I have seen to much of it come swell up and turn to junk. Why ? Not a fault of the OSB but the OSB exposed to moisture. If it is exposed then something else failed first. However Ive been on jobs that we were building in the rain and the OSB would either swell up or act like butter and not even hold a ringshank. Maybe because I saw so many problems in the early years of OSB that I still avoid it. I do think that it is a good way to build panels out of wood waste. I would use it before masonite. It is also pretty slick on a steep roof. As for floors I can get plywood at nearly the same cost when it comes to 1 1/8 inch.Maybe my conditions are a little harder.coast range of Oregon.Just read a reply on vinyl siding (yuck) and it mentioned they went to pull off the siding and all the OSB just crumbled to the ground.... but again was that the OSB or something else failing first.Since roof leaks can develop over time and I live where it rains everyday ( so it seems) I'll stick to plywood.Josh at Silver Hammer
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I plan on building a new house in about a month. All of the building materials estimates list OSB for the subfloor. My father in-law seems to think plywood is the only way to go. The difference in price would be about $400 for the entire house. What are the benefits of plywood over OSB. My father in-law thinks OSB will swell and break apart if it gets wet, but plywood is more resistant to water damage. Is this true? We plan on installing some solid hardwood flooring, some ceramic tile, some vinyl, and some carpeting. Does the subfloor under each of these materials matter? (we will also use concrete board under the ceramic).