Replies

1. 
   Piffin | May 31, 2002 06:24pm | #1

   I used to live near an LP plant. Still don't care much for their products.

   Excellence is its own reward!
2. 
   4Lorn1 | May 31, 2002 08:43pm | #2

   Maybe I'm getting to the codger stage of old. I shake my head at the housing going up with OSB for sheathing. I have been told by various carpenters that it is as good if not superior to plywood. I have yet to see any reliable testing demonstrating this.

   A small demonstration. Measure 3/4" from the corner on sheets of both 1/2" OSB and 1/2" ply. nail them flat at this point with a 8p nail into a subfloor. Pick up the opposite end of the plywood about 8" and try to pull the sheet in shear off the nail. If your like me the OSB has likely cracked when you lifted the end of the sheet or soon the corner tore off. The plywood may eventually give up, especially if you continue to lift the end.

   Case study. I was chasing masons and realized that a doorbell wire was now 4' down and cover by brick veneer. I remembered that the wire went down the wall behind the sheathing. Borrowing a hammer I hit the sheathing 4 times in one spot and had opened up a hole large enough to get my hand in and grab the wire.

   I pulled it up and threaded it down the wall to where I had pushed a doubled length of #12 through the still wet mortar to pull the wire through the wall without making the mason disassemble the wall. The sheathing was patched. Had this been plywood I would have had a much tougher job making the hole. Likely I would have had to rig a cord and use a 4" hole saw.

   If I was building a house I would spec plywood not OSB. I realize I would pay a premium for the additional cost of the ply but I think it is the superior product and makes a stronger structure. Does anyone have any research as to the relative strengths of ply to OSB? Or am I building the wall stronger than it needs to be? Would this additional strength help with hurricanes or earthquakes?

1. 
   BossHog | May 31, 2002 09:07pm | #3

   You like picking fights??? The OSB vs. plywood debate has been going on here for a long, long time.

   Hitting OSB with a hammer and knocking a hole in it isn't really a valid test of it's strength. You're not trying to design it for impact. Most applications of plywood (or OSB) is to provide shear strength on walls or support the shingles on the roof. Both products do an adequate job of that.

   I also prefer plywood over OSB a little, but I don't really think it's that big of a deal. Use whatever ya want and don't lose any sleep over it.

   Why do they call it "Oriental Strand Board"???

1. 
   4Lorn1 | May 31, 2002 10:48pm | #4

   That's what they say about the glorified cardboard with aluminum foil called Thermoply. Its used a lot a lot around here for rack strength. Strong enough? If that's what the numbers say. But for how long? Will it still be there if it gets wet? It rains a bit here. Will OSB last? What if it gets damp?

   Around here you have to install windows and garage doors with a wind and impact rating. Wouldn't having more impact resistance be a good thing?

   There are entire housing developments around here that have particle board clapboard siding installed over thermoply. I was called upon to install a receptacle in this stuff. I went to drill a 3/16" exploratory and had to hold back to keep from going pushing the drill through the drywall on the inside. When I pressed lightly with my thumb it went through both the clapboard and the thermoply. Both were damp. This is the stuff that is supposed to prevent the house from racking and falling down. Any rack strength was being provided by the drywall.

   After mounting the box. A story for another day. I found out that most of the HO were suing the builder and the manufacturers of Thermoply and the clapboards. Seemed just another case of someone building things that look like real houses as cheaply as possible. While I must say that OSB must be better than Thermoply it is a difference of degree and not kind. Inadequate, without regard to what the code says or how cheap it is, is inadequate. By any means it is not quality.

   <Rant Warning>

   Sorry if I rant. This stuff and roofs that wave to you as you drive by get my goat. Slam a door and the entire house shakes. $1,000,000. houses and they would be better sitting in a ditch or squatting in a refrigerator box. At least those can't fall down and kill you in a storm. It's a glorifies southamerican shanty town just better landscaped and decorated. The truth showed its ugly head after Andrew but was quickly covered up. Not enough people died for things to change much. Too much profit to be made selling overpriced, but roomy, cardboard boxes. Nearly homeless and they don't even know it.

1. 
   KenHill3 | May 31, 2002 11:31pm | #5

   We built a house for a friend of mine last year who is chemically sensitive. Convinced her to use all plywood subfloor, roof and wall sheathing. Not a shred of OSB in that house. I feel good about that.

   I do tend to shy away from OSB mostly because of off-gassing and its proclivity to swelling from moisture, but when you think of it, it's a pretty efficient use of wood. Certainly passes the requirements for shear.

   Someone told me that they had used a type of OSB for commercial form building that was put together with some kind of resin. No dimensional or structural change even when left out in the rain. Anybody know of this?

   Ken Hill

1. 
   Piffin | Jun 01, 2002 05:33am | #6

   That's the Advantech product. I've got some out on a job right now and the last three rains are just beading up on it like a plastic sheet.

   I don't have a problem with OSB products for wall sheathing (unless I'm hand nailing cedara shingles) but I don't use it on the roofs because of the sags you get with it. The original Q was about LP's version of it. The only loyalty LP has is to the stockholders profits. Customers, employees, and quality products don't even make their radar, in my experience.

   Excellence is its own reward!

2. 
   kueker | Jun 01, 2002 05:59am | #7

   I have used the LP high performance sub-floor on a few projects, and I think it's a good product. It stands up to rain well, holds a nail really well, and the tounge slips into the groove easily. The tounge also has notches cut into it to let the water run through. The water in the basement takes a while to dry up, but better on the concrete than on the sub-floor.

   In this area we have had problems with plywood delaminating.

3. 
   Howie990 | Jun 01, 2002 06:24am | #8

   Hey All,

   Didn't really mean to start a major war by my question. I have used Huber's Advantech, and although very skeptical at first, I was very impressed with its performance: as a sub-floor and a roof sheathing, it stood up to multiple rains with absolutely no sign of swelling or sagging. Up until I used advantech, I would never have imagined using an OSB for virtually anything. I am concerned about the glues and their outgasing, even though I've been assured that it is not a problem. That is why I don't intend to use it for subflooring, only for wall and roof sheathing, outside the envelope/vapor barrier. However, I am interested in LP's new product (although I'm not thrilled to hear that their business practices are noticeably bad). What is the brand name of the product that you used? Is it Topnotch?

   Thanks for all the feedback folks!

   Howie

4. 
   kueker | Jun 01, 2002 04:00pm | #11

   Yes it is called Topnotch. I have also used Advantech and I think Topnotch is comprable. But, with the Advantech we always have to drill holes in the subfloor to drain the rain water. I know you get what you pay for, but Topnotch is a little bit less expensive than Advantech.

5. 
   Howie990 | Jun 02, 2002 07:15am | #15

   Hey keek,

   I checked out LP's website and found 2 products they call topnotch - one is just "Topnotch" the other "Topnotch HP (high performance)". Do you know which you used? Thanks for the feedback!

   Howie

6. 
   kueker | Jun 02, 2002 03:57pm | #16

   It is the high performance. I didn't know they made the other stuff.

7. 
   MrsReese | Jun 01, 2002 08:00am | #10

   When you built a house to keep down outgassing, what did you use on top of the subfloor? I'm a goner with the multiple chemical sensitivities now. I have a plywood subfloor in an addition, but I don't know what to put on that before carpet. The rest of the house has 3/4" particle board under the carpet. That's right out.

   I've heard so many stories about bad sheathing, I think none might be a better alternative. I found 4 kinds of stuff under my siding when I decided to do HardiPlank. I just hated the tacky "contemporary" diagonal lap siding. I thought it would be the work of a weekend to just flick that off and throw up some stuff going horizontally. I didn't know what wonders I was to find. Plywood in some of the corners (thank goodness), gypsum board, some of that asphalt impregnated fluff board, and air. Just cedar nailed right on the studs. No tarpaper, not anywhere. The attic was ventilated by knotholes. Not a scrap of flashing or caulk to be found in the whole building envelope.

   The carpenter ants were having a huge time living it up behind that damp gypsum board in the squishy studs around the flashing free, caulkless windows. But up in the air-for-sheathing attic, there was a comparatively small number of squirrel and wasp nests. At least all the water that came in was able to dry up in the hot attic.

   Plus It was a lot easier to dispose of the the air-for-sheathing than the gypsum when I put up the plywood. Which I used instead of OSB because the studs in the attic section are about 3' apart which means I can't even use HardiPlank blind nailed like the rest of the house. I'm switching to the shingles up there and they call for plywood.

8. 
   rez | Jun 02, 2002 05:47am | #12

   hey B- sounds like you got a handful of house there. Nothing quite like that invigorating smell of a squirrel nest, second only to the lingering aroma of a bumblebee nest compacted over the window headers. Are you using pressure treated 2x's to replace your rot?

9. 
   MrsReese | Jun 02, 2002 06:23am | #13

   I used pressure treated 2x12s to replace the band joist that was home to some really impressive June Bugs and their larvae. I didn't use pressure treated studs, though. Should I have? I did the logical thing and used some flashing when I put on the replacement deck on the gone band joist side, and even more effective, extended the roof to create a good 4 feet of covered porch over the back door. Every door in Georgia should have at least a 4 foot roof overhang, according to my father, who has done tests. I believe him. I am implementing the fix. I had 4 exterior doors. They are all now covered. And I only had to replace 3 of them! The garage door I patched with two part putty and decided it would last a little longer. That little shed roof over it has made a great difference. The garage doesn't flood anymore!

   Actually, the places that were REALLY bad, are just plain gone. Around the chimney and a bay window in the bathroom -- I just removed the chimney and the bay window. The chimney wasn't even as tall as the roofline. Stupid cantilevered chimney. In the time it took my husband to go to Wendy's and get a combo #1, I had the whole chimney demolished. It took me considerably longer to repair the roof, etc. I have a nice new bedsheet that exactly covers the hole in the drywall on the inside. I pinned it up with binder clips until I get around to doing sheetrock. I'm sure bedsheets aren't code approved coverings for faced insulation. No candles allowed on that side of the room.

   And I built a new addition attached at the bay window opening, all sitting on doubled pressure treated 2x12s. I think I got it. Going on 8 years, but I'm almost done. Did you know Hardiplank left exposed for 3 years will still take paint? It voids the warranty, I'm sure, but still, that's pretty neat! That little unpainted piece was next to the gone chimney, though, and I'm going to have to tear it off to redo it with longer pieces. So I can't test to see if the paint lasts as long on the weathered Hardiplank as the stuff that was painted right away. It would have been a neat experiment. Maybe I'll save a piece and leave it out.

   Say, I wonder if you could use Hardibacker tile underlayment as a carpet underlayment, too? It doesn't outgas formaldehyde, and it's so dense it would probably cut down on noise. Not as cheap as particle board, but the 3x5 sheets fit in my car and I can carry them by myself. I might be on to something! It's only a 12' square room. Plus, I figured out I can use my Snapper Shears on the backer board, too, not just siding. According to the customer service guy at Hardie, the siding is actually THICKER than the backer board. Maybe I could use siding as an underlayment for the carpet. It comes 12' long. My husband would have a cow.

   B

10. 
    rez | Jun 02, 2002 06:35am | #14

    Ifyou hadn't said you were from Georgia I'd have sworn you were a yankee.

    Haven't been thru Georgia in years. Do they still have those big fires at the side of the interstate where they try to burn up that plant that accidently came over on a cargo ship and is over-running everything?

    Edited 6/2/2002 12:08:21 AM ET by rez

2. 
   FrankB89 | Jun 01, 2002 06:45am | #9

   I always let my clients make the choice between the two after giving them my most polite unvarnished recommendation for plywood.  I also usually recommend pressure treated plywood sheathing for the first couple of feet of walls that will eventually be bordered by landscape plantings because (in my coastal climate) I've too often found rotted sheathing where unpruned plants were enabling moisture to hang around and eventually compromise the siding and the structure behind it.

   I don't always get my way because cost is often an attraction for OSB.  However, I do put my foot down when it comes to shear walls because I'm  thoroughly convinced that plywood, when nailed to spec (and usually glued, as well) is vastly superior in resisting shear forces, resistance to nail withdrawal and bonding with glue lines.