Hi there all ,
Been here a few months and finally decided to try postin……most excellent site yall …..great practical info.
Any hows…my question ….we do all our frame sheathing using CDX ply……building regs allow the use of OSB…in fact they practically encourage it here….(Ireland )….however I have no info on its behaviour in wet conditions , I know CDX performs pretty well and would like to hear of some information from the real world on OSB as opposed to the manafacturers spiel.
Thanks in advance
Paud
Replies
We'll forgive you since you are from such a beautiful place and aren't aware of the osb wars we've had here. I say this with a grin on my face worthy of any leprechaun and my German/American eyes are smiling too.
OSB has com a long ways since the old waferboard that would fall apart like cardboard at the first sign of rain drops. But it still hasn't earned the place it has been given by factory testing, etc. I will use it for wall sheathing but not for roofs. I see too many places where it telegraphs through the asphalt shingles to fill me with confidence.
That's just one man's opinion. I'm quiet sure you'll hear others. If you want to jump the gun on those comments, just use the search button to go back a year and read away.
Annnnnnnnnnndd!...WELCOME TO BREAKTIME!
Excellence is its own reward!
Well, in my world, OSB gets used out of cost considerations more than out of my own personal preference. I'd much rather see CDX used on everything. OSB has come a ways, but I'm still not a big fan. If you can afford to use CDX, don't fix what ain't broke. Bless you all for giving us Guiness.
I'm with those two. There's only a few things I'll use it for. Roof decking and exterior walls aren't even considered.
make four for CDX , osb has very little structual integrity to it so exterior walls,roof is a verbotten. and i've also noticed when water gets to it it swells more than CDX so with the osb mash that tells me longevity is an issue........... i build for the long haul..imho.. cheers bear
Edited 10/26/2002 10:51:11 PM ET by the bear
Welcome to Breaktime. I have to side with the others, T&G ply subfloors, CDX wall sheathing and roof decking are all I use. It is causing me some shame to admit that I am putting OSB on the interior walls and ceiling of my personal shop due to budget constraints. I keep telling myself it will be OK though, since the shop is dried in and moisture won't be a problem.TCW Specialists in Custom Remodeling.
Much appreciated in getting your viewpoint everyone , gonna stick with the CDX after all .
Interesting line about the roofsheathing , here we batten the roofs with 2 x 2"s over the roof membrane every ten inches or so to take slate or rooftiles .I know its primarily shingles you guys use , when ever you use slate or tiles are the codes still asking for roofsheathing in your part of the world ?
( Just bein nosey )
Paud
Welcome, and here in B.C., we try to avoid "Beaver Barf"... when called for , we go ply on high-end homes, but you see lots of OSB on apartment buildings...If it is to be, 'twil be done by me..
"Beaver Barf"
cute . . . Steelkilt Lives!
The only CDX that I've seen that is "trash" is the 3-ply half-inch CDX.
Everything else is just fine.
have had very bad experiences with syp cdx both 3/4'' and 1/2"
stuff , when it gets wet, delaminates terribly and warps extensively.
Are you sure it was CDX?.
Excellence is its own reward!
cdx 1/2" syp and T&G 3/4 subfloor syp with the 3/4" I've had entire sheets delaminate in the middle ply usually the factory rep. will say sorry must not have been enough heat enough pressure enough resin or any combination of the three. Their glad to replace the sheet but of course cant help me with the labor costs. Boy when you glue and nail with ring-shank nails that stuff is murder to replace.
With the 1/2" I dont get as much delamination as warping. This really becomes a problem when it happens at a butt joint and you get the combination of a dip and a ridge making a difference in the roof of about an inch....Tough for 3-tab to cover that.
taking cost and final product into consideration , I would use osb gapped properly with 25 year composite shingles
Consider trying fir rather than SYP. Many of my customers use SYP only during our dry season and then switch to fir as soon as it gets wet outside. You might look as well at the 4ply version of 1/2" cdx which has substantially improved resistance to warping over the 3ply. I'm also interested in how much rain gets on your projects before they're dried in. Much plywood thought to be exterior is actually referred to as "EXP 1" or exposure 1 by the APA. It isn't designed for long term moisture exposure, only what might reasonably be expected during the course of normal construction. I've tried to get the particulars on exactly what the APA considers "reasonable & normal" but never gotten a clear answer. But the intent is obvious. True exterior ply is not as commonly available as you might think. For delam subflooring, mills will usually credit back to the lumberyard and they to you the price of replacement ply plus a small labor charge, provided you have clear photos showing the delam areas AND their mill stamp on the bottom side. If you have an ongoing problem with delam, talk with your supplier about it. Beware of yards that offer cheaper subfloor but without any grade stamps. If there's a problem with that ply, unless the yard will stand behind it, you're out of luck.
Al
Hi Al, thanks for the info , yep agree 100% that the fir is the way to go unfortunately sometimes I must use what the customer chooses.
When I mention the problems they might have if the syp gets weather, they usually weigh the cost versus the chance it might get rain and most often go the osb or syp cdx route. From what I've been told by a salesman the exposure 1 rating means its supposed to take 10 rains before it starts to have problems. With the syp some loads will do alright, but the ones that do go bad do it in a big way.
With poor glue application at the mill, SYP ply can come apart within hours. We had an instance about two years ago where we put about 150 sheets of really bad 3/4" T&G SYP ply on jobs without knowing it. The rain came one morning & then it got hot & sunny in the afternoon. The phone started ringing off the hook. It was a big deal to us and to our customers. We were demanding the mill's rep get here pronto. They, after declining our hospitality, pointed out that ply is being glued up on production lines that can be moving over 30mph. When a product is being made that fast, even though the problem is almost immediately detected, some gets by before the corrections can be made. That's why the better mills tend to be pretty cooperative about reimbursement for material and labor. The guy said even though we had a larger claim than normal, to follow standard procedure & document builder, lot number, qty, & provide photos, which we did. I even put in for double the normal labor rate because my customers said the existing one was not sufficient. About a month later, we got our credit and divied it up to everyone who'd been affected. I guess the mills just see it as a cost of doing business.
Al
I vote for osb. I like the consistency and the flatness as well as the price. For an upgrade I would rather add thickness than go to cdx. Advantec is a superior product for subfloors particularly if they will be exposed to a lot of water. We have had some delamination problems with plywood subfloors that have required removing sheets of subfloor after the interior walls were up. That is hard to live with. Of course every material has it's strengths and weaknesses and even my partners don't agree with me.
I also vote for OSB; all the problems noted about it (swelling, delaminating, etc., etc.)...are problems with the CDX we get in my area. Here, CDX is nothing but expensive trash. I might feel differently if I had access (or the funds), for better materials, but it just ain't that way. OSB has come a LONG way in the past ten to fifteen years...I'm sure it wouldn't receive the bashing it generally does if people got to try some of the newer products.
Troll,
Welcome aboard.
If your building under the old bridge, go with CDX. It will put up with the foot traffic much better...
CDX...spend the extra cash, one unexpected rain day and you`ll be glad you did.
J. D. Reynolds
Home Improvements
"DO IT RIGHT, DO IT ONCE"
Welcome Troll
Give Ireland back to the Irish as my man John Lennon said (and my dads a Brit...(tough)!....ohhhhh the CDX question.right.....and the movie The Commitments totally was incredable. As are The Saw Doctors.....OK OK sorry....I really hate OSB. Hate cuttin' it and hate nailing into it. All I can say to you is, besides my reasons try saturating a scrap of OSB and a scrap of CDX and see fer yourself. CDX always wins out. Thing is...its more expensive specially when sheathing a whole house...but so are good tools.
Be well
Namaste
andy
It's not who's right, it's who's left ~ http://CLIFFORDRENOVATIONS.COM