Replies

1. 
   migraine | Sep 09, 2003 11:54pm | #1

   How about take this question one step farther (do you mind if I cut in??)   Is it worth to use thicker osb board(because it's cheaper than plywood) and get a better subfloor for the same amount of money as compared to a thinner plywood subfloor??

   Just had a builder say that 3/4" ply subfloor was better than 1' or 1 1/8" OSB subfloor.  Our home should begin construction in about 2 months and the dry season is now past for the Pacific Northwest.  Too many various opinions on how weather affects OSB vs. ply subfloors.  I need a little education on this matter,

2. 
   dIrishInMe | Sep 10, 2003 12:06am | #2

   I can't speak to the other OSB products you mentioned, but I've had good luck with Advantech, especially in situations where the floor got repeated wettings while framing was finished.  I've had bad luck (if luck has anything to do with it) with "no-name" OSB products, and delaminated plywood is a bummer... no 2 ways about it.

   Matt
3. 
   andybuildz | Sep 10, 2003 02:10am | #3

   I think I'll be using Advantech on all my floors if friggin' Dubya didn't send it all to Iraq....I also may use 1/2" Advantech on my wall sheathing.

   Be rained on,

                    andy

    The way we regard death is critical to the way we experiance life.

   When your fear of death changes, the way you live your life changes.

   http://CLIFFORDRENOVATIONS.COM

1. 
   Piffin | Sep 10, 2003 04:02am | #4

   No question but that the Advantech is better than plywood especially if wetting is likely!

   And I would recommend running away from ANY LP product..

   Excellence is its own reward!

1. 
   andybuildz | Sep 10, 2003 04:17am | #5

   Pif,

        With your blessing......lol.......its done.

   PS..I have my excavation guy here now......forget his screen name but I'll let you all know tomorrow so you can lure him in from lurking.

   Be well all

                andy The way we regard death is critical to the way we experiance life.

   When your fear of death changes, the way you live your life changes.

   http://CLIFFORDRENOVATIONS.COM

2. 
   migraine | Sep 11, 2003 04:54am | #6

   Can you give a better understanding on why you think this stuff is better?  I'll be needing underlayment in the next 6-8 weeks and I really don't want any regrets on my choice.  I 've seen too much 1/2 ply sheeting delaminating and buckling from the last few rains on the coast in washington

1. 
   Piffin | Sep 11, 2003 04:44pm | #8

   Three years ago, when framing a new two story in winter, my lead framer asked me why I wasn't using the stuff since we were bound to see ice on the deck. I had never heard of it back then and was sckeptical of any osb product since I've seen the worst of what it can do.

   Then I happened to be on another contractor's job a couple of weeks later. His Advantech decks had been exposed to weather for two months of moisture and were still smooth hard and tight. Then I started reading here and elsewhere about it and have used it several times since with nothing but good results. Plywood, by comparisson is more prone to delamination on a gamblers plate. With he advantech, I'm sure..

   Excellence is its own reward!

2. 
   PenobscotMan | Sep 11, 2003 06:31pm | #9

   Funny thing about PW buckling in the rain. A while ago I was trying to fit a plywood deck on a small sailboat with considerable camber (= curvature in the beams or "joists"). There would have been considerable strain on the fastenings, so being aware of how much PW warps in the rain, I tried to turn this defect to my advantage. I built a form with yet more camber than the deck beams, temporarily attached the PW to it and steamed the hell out of it by piling on rags soaked with boiling water. I did this for a couple of hours, refreshing the water as it cooled. Took off the PW and it was as flat as it was at the beginning.

4. 
   JLazaro317 | Sep 11, 2003 05:08am | #7

   The Advantech is nice, I used the Topnotch HP in my own house and was very happy with it. The notches are nice for keeping the floor drained. Currently we are using the Potlatch product and it's holding up very well.

   We used 3/4" ply up until this Spring. We couldn't get the premium product we had before and started having problems, so switched to Potlatch. Wouldn't recommend regular 3/4" OSB unless you can guarantee it won't get wet.

   John

   J.R. Lazaro Builders, Inc.

   Indianapolis, In.

   http://www.lazarobuilders.com

1. 
   dIrishInMe | Sep 11, 2003 07:27pm | #10

   About 4 years ago, I did a little test.  The building supply we were using did not sell Advantech floor sheathing, like we ordered, and the salesmen said - "oh don't worry our xxx OSB is just as good as Advantech"...  We used the xxx OSB (can't remember the brand).

   I took a scrap piece of the xxx OSB and a scrap piece of Advantech I had from a previous house and put them in a 5 gallon bucket of water, and set them out back of the house we were building.  Towards the completion of the house - about 4 months later, I went out there and retrieved the bucket.  The xxx OSB had swollen up to about 1" and was flaking some.  The advantech was still exactly it's original thickness with no flaking - the only ill effect was some discoloration from the dirty water.  

   BTW - that house saw *several* rains and the house wasn't fully dried-in for about 3 weeks.  The xxx OSB floors were very uneven almost to the point where I thought it might be able to be felt through the carpeting...

   Matt

1. 
   Piffin | Sep 11, 2003 11:30pm | #11

   We don't have the end of that story 'till we know what you told the guy who sold you on brandX.

   Excellence is its own reward!

1. 
   dIrishInMe | Sep 11, 2003 11:33pm | #12

   We changed building material suppliers.   Not necessarily for *that* incident, that was just one in the list.

   Matt

2. 
   JLazaro317 | Sep 12, 2003 03:25pm | #13

   We've done the tests also. I agree that all OSB's are not created equally. I would NEVER use regular 3/4" OSB in a customer's home. All of the weatherproof OSB's have the "no sand" warranty so we've tried Advantec, LP Topnotch HP, and Potlatch. My favorite was the LP because of the drain notches. Advantech was an excellent performer and the Potlatch is also a very good performer. This Spring/Summer we've had lots of rain and I've seen a few houses with 1 1/2" of standing water inside (perimeter plates weren't cut yet) and after they dried out, no swelling.

   Just my 2 cents,

   John

   J.R. Lazaro Builders, Inc.

   Indianapolis, In.

   http://www.lazarobuilders.com

1. 
   zztop | Sep 12, 2003 03:43pm | #14

   Are you saying you would never use 3/4" OSB (any brand) for a sub-floor; only 1" (or thicker)?  If so, do you think 1" gives a much better floor than 3/4"

   Thanks to all for your opinions.

   vlperk

1. 
   UncleDunc | Sep 12, 2003 04:43pm | #15

   All else being equal, a 1" floor will be 2.4 times as stiff as a 3/4" floor. That's a 58% reduction in deflection for a 33% increase in thickness.

2. 
   dIrishInMe | Sep 13, 2003 12:29am | #16

   Care to elaborate?

   Matt

3. 
   UncleDunc | Sep 13, 2003 02:11am | #17

   Think of a floor membrane as a series of tiny beams side by side. The vertical dimension is what you would call depth in a beam or joist. The stiffness of a beam varies as the cube of the depth. The depth or thickness of 1" OSB is 1/3 or 33% more than the depth of 3/4". The cube of 1.33 is 2.37, so the 1" is 2.37 times as stiff as the 3/4". Deflection is the reciprocal of stiffness, so the deflection of the 1" is 1 over 2.37 = .42, or 42%, which is 58% less than the deflection of the 3/4"

   Of course that calculation neglects the fact that the subfloor doesn't just stop at each joist but is continuous. I haven't tried to figure out how that continuity affects the stiffness of the whole floor.

4. 
   JLazaro317 | Sep 13, 2003 04:46am | #18

   No, I was referring to regular 3/4" OSB. I think most if not all of the weather proof (resistant) OSB products are great. For 16" on center floor joist, I think 3/4" is adequate. 1" will give a stiffer floor, but is it worth the extra cost? Depends on the situation (ie. span, joist spacing, etc.)

   John

   J.R. Lazaro Builders, Inc.

   Indianapolis, In.

   http://www.lazarobuilders.com

5. 
   Timuhler | Sep 13, 2003 06:05am | #19

   I'm just curious about Advantech.  We build near Seattle and get a ton of rain.  We have had really good luck with TopNotch and the GoldEdge. 

   I've been reading good things about Advantech for the last couple of years and I would like to try it.

   Here is my question to everyone who has used it (questions).  What price per sheet of 3/4" did you pay last spring and what do you pay now?  Have any of you used the new version that has a nailing guide stamped on it?

6. 
   briankeith | Sep 13, 2003 06:10pm | #20

   Personally I think you would be happy with the advantech in your neck of the woods. It is one tuff product.

   We are on our third home with the new spotted sheets, The marks are right on. But there are a lot of them. 16" 19.2" and 24".

   Prices.......

   I think about $20.00 this spring and now $30.00 and rising.View Image

7. 
   Timuhler | Sep 13, 2003 08:24pm | #22

   We are paying 27.50 for the GoldEdge, so Advantech sounds like a good deal to me @$30.  I'm going to look into ordering some of that for the next house we start.

   Thank you for replying (and you Andy)

8. 
   andybuildz | Sep 13, 2003 07:45pm | #21

   current price here on Long Island is $25 a sheet of 3/4" Advantech The way we regard death is critical to the way we experiance life.

   When your fear of death changes, the way you live your life changes.

   http://CLIFFORDRENOVATIONS.COM