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Hey gang,
Just a lowly cook over from Cooks Talk needing some materials advice. I’m building a storage shed on the pondorosa and was wondering the pro/con of useing 3/4 OSB vs 3/4 plywood on the floor and roof.
TIA
Tom
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Tom,
Its your storage... but I recommed you to use those osb, as for floor, use 3/4 osb with T&G because it last longer and strength.... About your roofing, it doesnt requires 3/4 thickness... in heavy snowy area, they use 5/8's osb... depends on your roofing framing layers,, if its 16 o.c. then use 5/8's if its 24's you can use 3/4 but it doesnt requires,,, and good luck to layer those 3/4's its pretty heavy.... Matt
*Thanks Matt, No heavy snow load, and 16 oc. OSB it is. at $8 to $10 per sheet that will add up, Maybe DW will let me make a bigger shed :)Tom
*Just to confuse ya...I prefer ply......but you still don't need/want 3/4 on the roof. 5/8th is plenty. With 16oc you could go to 1/2 and be prefectly fine up there to shingle. Jeff
*Plywood stands up over time much better. Just remember to use CDX. The only time I use OSB ifs for sheathing on my walls.
*i took down a shed that was sitting on a platform that was half osb, half plywood. i was able to lift the plywood sheets, but the osb sheets had turned black and become a pile of mush. just my two cents worth!
*you know what OSB stands for?one side bad
*Tom, I agree with Bill Burns, had the same experience too.
*I don't have much of a preference between plywood and OSB, but a plywood floor might be a little easier to sweep.
*Greg,Oriented Strand Board.
*you know what osb stands for "old swell board"
*Tom, I'd recommend 3/4" T&G CDX ply for the floors and half-inch CDX 4-ply plywood for the roof.Avoid 3-ply half-inch ply...Many like OSB, but I have long term concerns over edge swelling and its ability to hold nails.
*I don't have the numbers with me but one of the things Lstiburek noted during his presentation was that plywood has a relatively low perm when dry but a high perm when wet - like near 1 US perm to 4 or 5 best I can recall. OSB is similar when dry but only increases a little when wet - thus accounting for it's not drying as quickly as ply. I'll check my notes and addend these values if far off.I did hear several builders speak very well of "Advantec" (sp?) for subflooring - swearing they would never use ply or ordianry osb again. Not only was it seemingly unaffected by rain and moisture but the t&g edges were much better at aligning and it "seemed" stiffer.
*I'll second Ron's comment about sweeping the floor... I built a shed with 3/4 T&G OSB a couple years ago. While I don't have any structural issues with the OSB floor, the flakes/chips do make it difficult to sweep up well. As for the roof, it doesn't matter so much if it's a shed. I'm replacing a porch roof on a rental property next week and using plywood because sometimes tenants climb out and stand/sunbath on the roof (then I have to yell at them). If the roof leaked, and the OSB turned to mush, people would fall through quicker than Ply in my opinion. Plywood will delaminate and swell with the same leak, but it will hold weight better before it fails completely. For a shed keeping your garden tools dry...save $ and go with the OSB though.-Stray
*16 oc and no snow and desire for spending less bucks = 3/8 ply on roof (stamped 0/16). Got it on my barn and its been good for 30 years.
*Tom,I hate to go against all of the pro's that have suggested ply vs osb but heres my .02.Go with the osb. 7/16 on the roof and 3/4 t & G on the deck, you don't need 3/4 on the roof deck. I don't see the need to spend the extra $ for your application. In my neck of the woods plywood is about 50 - 60% more than osb, save your money for other things.I have a 10 x 14 building that I built 7 years ago. It started out as a shed/workshop and is now my office. It has 7/16 osb on the roof deck and 3/4 on the deck. I have had no problems with either. I have a piece of 7/16 OSB that has been in the back of my pickup truck for 3 months in the rainy NW and no signs of delamination, swelling or flaking.I'm just a humble Diy'er but IMHO save your $ and use OSB.Scott
*If you leave a sheet of OSB in the rain for 3 or more rains it will swell. After 6 -8 rains it will begin to fall apart. On the average shed you will save about $80.00. Some may see that savings as a bargin while others may want to have more security.
*Ron,I just put a tape on the 7/16 osb that has been in the back of my truck for 3 months, it still measures 7/16. The truck is parked outside in Seattle. Maybe our OSB is different here in the NW.The OSB shouldn't see much water if the shed is constructed properly, if it isn't then it probably won't make much difference what is used it will all eventually fail.BTW how many of the anti-osb crowd use TJI's. I realize we are talking vertical vs. horizontal application but if OSB is so failure prone I wouldn't think it would be used anywhere.Scott
*In an out door shed there is plenty of moisture above , below and all around. In a home floor system I think there is plenty of protection from the elements. You would not catch me using them(TJI) in a crawl space. If I seem anti OSB it is only from the years of roofing and construction experience of seeing it falling apart. We have seen it installed as roof sheathing and even the manufactor states it must be roofed within 2 to 3 rains. If the manufactor is worried then so am I. On those same homes that saw 2 or 3 rains I have seen first hand the swelling problem. If their are so many of us anti OSB contractors out there, it must say something about the product.
*Hey Tom,Spend the extra few quid it takes to buy plywood.It'll serve you better in the long run.My opinion,Ed.
*I think a lot of the "old guys" get OSB confused with Aspenite. Either way, OSB = recycled lumber. Use it where you can, plywood where you can't.
*I'd go w/ whats cheaper . Dave
*OSB=recycled lumber. Where did you come up with that? I know that the manufacturers talk about chipping the cut-offs from sawmills, but that is a small percentage. The majority of OSB is manufactured from clear-cut operations either on mono-planted tree plantations or from clear cut "waste trees". I do not know of any waste trees. Certainly aspen is not a waste tree, nor are the species of pine, spruce, or fir they use.Futher more the glues used to bind the chips together do not lose their toxicity until well after decomposition. The manufacturing process uses considerable energy in production. The entire process continues to grow while employing less people. Mono-planted tree plantations are not sound environmentally for many reasons. It is just another petro-agri-business run amock.OSB does not need exposure to water to swell. It will do so under normal humidity conditions such as crawlspaces and wall cavities. Also once the swelling process begins it will not return to original . OSB does not hold nails or screws all that well. Fastening into OSB causes fracturing of the glue/chip bond and eventual failure. Check a roof or siding application that relys solely on the OSB sheathing to hold nails.It is another product we have been sold a bill of goods on and the future will hold the surprises as the homes we built with it start to fall apart. I agree that this also includes TJI, BCI and/or most other engineered lumber products.walk gooddavid
*Now. Lets throw some dirt on this one and let OSB drift off into the sunset, never to be seen or heard from again. Kinda like the pet rock.
*I agree Ron. I confess I have a growing passion against engineered wood and OSB in particular. I sometimes get carryed away.walk gooddavid
*I also agree Ron. Since I disagree, 100%, with the anecdotal evidence provided here, particualry by David, let's just put this one away. Walk anyway you want to. Jason
*http://www.osbguide.com/sba.media/sba.media.pdf/TB116.pdf
*Allyson, the link you posted is not at all a neutral position. It is like asking ATT who has the best phone service and expecting an honest answer. It says in the article, rep. for OSB. If you want the truth ask the people who use the stuff to let you know. So far I would have to say the plywood crowd is standing a little taller with more to come. As far as I am concerned its a no brainer on what the better product is.
*When plywood starts giving me a 50 year warranty against warping, cupping, & delaminating and no sanding, etc. Then I'll switch. Advantec offers a 50 warranty for the above and another company offers a similar warranty. I DO use it. I've had plywood swell before the roof was dried in too.Billy
*allysonWhere do i get info on Advantec?? how much is it a board?? I have seen many homes made with OSB flooring and it works fine. i think if u keep water off it and keep it out of humid areas its fine. OSB is also alot cheaper than plywood too.
*1-800-933-9220 ext.5100AdvantecBilly
*Jason, It appears that 99+% of the information given is anecdotal, ie, based on personal, interesting observations in this case concerning OSB. But though personal it is still experience.If you want some other sources than my anecdotes , read "Building Blind" January 2001 issue of BUILDER magazine. Or I think it was October 2000 issue of JLC with a short article on "swelling in OSB."I am not sure of the issues but AUDUBON magazine had an article on the manufacturing of OSB. One short article concerning aspens in Manitoba (again for OSB production) is bt Ted Kerasote in the January issue of AUDUBON (www.magazine.audubon.org/content/content0101.html.)Or contact THE FOREST TRUST (www.theforesttrust.org) and ask them about forestry practices regarding the manufacture of OSBOr check with the EPA and the list of fines for violations associated with OSB production.It could go on and it does, but I enjoy sharing my anecdotal information and walk good
*The bulk of Canadian OSB does not come from Manitoba, in fact I think very little lumber does. If there is no such thing as a "waste tree", then build with concrete. OSB is intended to be protected from the elements, as is reg ply. If you live in a very humid area, don't use OSB. Here in southern Alberta it's quite dry, everyone uses OSB and no one has problems.
*Oh, anecdotal information is fine; that is after all, what we're here for. I think, however, we have to remember that since all of us are from vastly different parts of continent, and have available to us much different products, we need to be just a little careful in making really, really broad statements when someone is looking for help. That being said, when I read many of these posts I've got say "what the heck?" My experience is just the opposite; plywood in my area, even some of the 5-ply CDX, basically sucks. Delaminiates, warps, twists, swells, and that's before we even use it. I have not experienced most of the problems that others seem to with OSB, and yes, it's been exposed to rain for more than three days, etc., etc. And the swelling we do get, such as on floor edges, really isn't any worse than what I've experienced with the ply available in my area. Sanding edges is the way it's done around here before carpeting goes in. So that's why I say I disagree, but really didn't want to get into it. One says "it swells too much" and somone else says "no it doesn't". Kind of sounds like kids; we can go back and forth all day.The same goes for nail and screw withdrawl resistance; I can remember this coming up before and seeing actual test data by JLC or perhaps someone else. I can try to find it again, if you really want, but I always thought the gist of actual testing was that there wasn't that much of a difference given similar circumstances. Finally, David, I really don't want to get into the whole environmental issue, but we can if you want. I got the opportunity a couple years ago to tour the upper midwest and parts of Canada with a buddy who was a timber association person. The trip was really about fishing, but I had the opportunity to visit a couple dozen mills and tree cutting operations (both on public land and private farms). I am just not convninced that engineered products and their production are any worse long-term, for the environment than any other product. I also wouldn't trust the "forest trust" for impartial information any more than I would Willemette or a lumber company. Seriously, however, if you want to discuss this furhter, please follow me over to the Sustaining Our Environment forum and let's post this question there; I think there is a lot more information and discussion on this topic on that forum than this one, and there are more people on both sides of the actual indsutries (the environmental industry and the timber people) who can provide more insight than you and I passing links off to each other. ThanksThe address is:http://www.nature.net/forums/sustain/
*Jason, We learn from our experiences and by discussing with others about their experiences. Regional conditions are different and can affect performance. I live in a relatively dry climate and have experienced moisture related problems with OSB and plywood. They seem, in my experience to affect the OSB more so than the plywood. Also they seem to continue with OSB, once it swells it stays. Other people and reports from other areas have tended to verify this. As far as nail/screw holding ability, again personal experience coupled with other related experiences leads me to make that claim. I have not even addressed longevity of the product.My biggest complaint against OSB is environmental. And I thank you for the link, but I believe this forum should be the place to discuss environmental issues. As builders, archetects, contractors even as labourers, we should be aware of the products we use; we should be aware of the entire life cycle of said product, what requirements are needed in manufacturing, how it affects the environment, how sustainable a product is it, what becomes of it once it's effective life span is over. We have a responsibility to our clients and ourselves to choose wisely. As far as THE FOREST TRUST, their work is towards sustainable forestry; working with local communitys and individuals to establish and maintain healthy, productive and sustainable forests and employment. An excellent goal. walk gooddavid
*Thanks David, for the links. The Audubon society link was interesting, but really wasn't about OSB; it was about harvesting practices. They merely made OSB from the timber they cut; bad harvesting practices are bad harvesing practices, whether the timber is used for OSB or Plywood or anything else. And I didn't see anything on the Forest Trust homesite about OSB; but then again, they don't have a search engine for their site. If you have a specific page to show, let me know and I'll check it out. Thanks.
*Advantec - "Sure, you've heard of AdvanTech, the revolutionary new engineered strand product that's the latest rave in the construction industry. Follow the AdvanTech link for the full story". This company has a warranty for 50 yrs on this product, which by the way I never addressed. Standard OSB is what I addressed. There warranty is as long as the company lasts and there product. It may be a great product that I have not used yet but to choose a product because of what there sailsmen tell you is foolish. I go by what I see. That is what I stand behind. Myself. Not some "the latest rave in the construction industry" thank you. At the advice and views I have heard hear. I will give this company and its "the latest rave in the construction industry ", a try and will use it on my next home product for myself. I will decide from there if I will back it or not. As for the OSB installed on all those homes I dealt with in the 90's Good bye . I have so far seen someone say it has the same pull out streanth and swells at a slower pace than plywood. These are just out right wrong and if we walked out in my yard it would be all to easy to prove it.
*Jason, Sorry I was not more specific. A good article by a fine writer (check out some of his books if you are interested). The specific content was on aspens and Manitoba in more specific.I read alot and do not always catalogue information for future need. I burnt out on political activism back in the early 80's. Being a builder though and seeing what is happening in building (and maybe having a daughter now) has rekindled my ardour. I will try to find some good info for you.I am all for sustainable forestry and working with wood, but real wood not engineered. We all make compromises to eat. I draw the line with plywood. I wish i could go back to sheathing with boards.Mike, Waste tree is a justifying term created by industry to allow the public to accept their timber practices. Aspens in particular are by industry considered a waste tree, yet provide valuable habitat for many species, throughout the range of the species. As far as building with concrete, it has it's place, but I like building with wood, think it is an excellent building material and with siustainable forestry can provide habitat and lumber. walk gooddavid
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Hey gang,
Just a lowly cook over from Cooks Talk needing some materials advice. I'm building a storage shed on the pondorosa and was wondering the pro/con of useing 3/4 OSB vs 3/4 plywood on the floor and roof.
TIA
Tom