Wet OSB - Help!

Started by georgevacabin, October 20, 2008, 08:28:19 PM

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georgevacabin

Hello All,

Got on site today to find that my tarp did not fair well in the few months since my last visit.  Several sheets of the T&G OSB for the subfloor are soaked.  Can they be put down wet or do they need to be replaced?  *&$^##^% Rain! >:(   I would move to plywood but too expensive.

glenn kangiser

Depends, George.

If they are expanded they will not go back.  If the are within your tolerance and strong they could work, but they likely won't take much more.  I hear Avantex does better where it may get wet.  Drill holes to drain where water may stand.
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

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georgevacabin

Hey Glenn,

Thanks for your prompt reply.  Yes, there are several that have expanded.  Not sure how many.  Got here just before dark.   :(  Fortunately, they have built a box store nearby.  I'll have to work my tail off as I only have two days here.  Thanks again!

Redoverfarm

George if these are pieces that have not been put down yet I believe as much as I hate to say this is to replace them.  If they have soaked up water and swelled up they likely will not decrease in thickness.  If they are still within a reasonable thickness of what you bought they might be OK.  It is not uncommon for OSB to gain 1/3 more thickness if left to get wet.  They are like a sponge. 

If these are sheets already nailed down and there is not that much swelling it can be taken off later by sanding the joints to create a level surface. 

There is nothing more aggrivating than trying to sand down high spots later(usually joint seams) to get an even floor. Depending on the flooring you are going to use such a  vinyle flooring it will wear at the seam location.  Tile will crack or joints crack.  Hardwood has even worked loose if it is on a teter effect.

Sorry to be the bearer of bad news but this happens more than you think.   

glenn kangiser

My pleasure.

G/L, George. :)

...and what John said.
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

Please put your area in your sig line so we can assist with location specific answers.


MountainDon

Ditto John and Glenn.   :(   That's one of OSB's shortcomings.   

Just because something has been done and has not failed, doesn't mean it is good design.

MikeT

Is this the Edgegold 3/4" T&G OSB?  If so, I had it down on my floor and exposed on the Oregon coast during the wet winter for a few months, and I didn't have any swelling problems.  I did knock holes through the floor where the water wanted to pool.  Once it dried, all was fine.

I would make real sure it has truly swelled up before giving up on it.  But if it has indeed swollen, then you really do need to get new stuff.

If you wanted to go with plywood, could you get away with using 3/4" plywood and getting the Simpson plywood clips instead of the T&G?  That would be cheaper than T&G but would only work if you were planning on covering the subflooring with something else.

mt

georgevacabin

Thanks for all of the tips.  Turns out that all of the OSB flooring had to be replaced.  :(  I did not have the flooring nailed down - just laid on top of the platform and covered with tarp.  However, the tarp apparently was not strong enough.

The sheathing for the walls were covered separately.  I should be able to finish the floor tomorrow and then see what condition the wall sheathing is in.

Speaking of the flooring (and I really feel like an idiot asking this question), the ends of the first row of 4x8 board is not landing on the joist.  I know that some of my joist are not exactly 16 oc.  d*  Thought of toe nailing it into the joist.  Is this going to a big deal going forward.  Not sure how I would correct it at this point.

 

 

Redoverfarm

Sorry about your water logged OSB but unless you can get a roof over it fairly fast it doesn't stand up.  After seeing what my floor went through over the winter it made me a believer in Advantex or Surefloor.  Yes it cost a little more but not by comparison with water damage.  Since most builders here are weekend warriors or have little time to complete a project from start to finish in a short period of time. A roof is not always possible after flooring framing and deck is laid.  Hopefully some will learn by your troubles George.  Thats what it is all about isn't it.   Good Luck.

John


MountainDon

Quote from: georgevacabin on October 21, 2008, 07:33:28 PM
the ends of the first row of 4x8 board is not landing on the joist. 
The panel end is not falling on the joist at all?  

As far as correcting, that's not real easy. All you can do is band aid it.

Likely the best solution is to sister a 2x4  onto the side of the joist where the subflooring doesn't have something solid to support it or be nailed to. You should have no less than 3/8" of the joist under the subflooring panel end, IMO. You want good support as the subflooring is the basis for anything and everything that goes on top.
Just because something has been done and has not failed, doesn't mean it is good design.

Redoverfarm

George sometimes the ends can be OC but the middle is bowed.  If that is the case you can push or pull the joist in position.  IF the ends are not OC then Don;s solution is the best.  I would check on down the line as well.  If you got off that would mean that you would have to sister all the remaining joist.  If you are constant with the OC without sistering the first sheet but your building is square and at it's proper demensions then you might want to cut the first sheet narrower and then add a piece at the end of the run. Let's hope it is just one out of place.

georgevacabin

Thanks for the tips guys.  I will be back at it in the am.  I'll post tomorrow night to let you know if I am way off or not.  Take care.

georgevacabin

Hi Folks,

What a day.  MD - took your advice and sistered (brothered, mom, and popped too!) 2x4 for support where needed.  I should be able to finish the flooring tomorrow.  Lots more rookie mistakes (Redoverfarm - I will continue to be an example of what not to do d*)

So will the OSB be okay for a month if I cover the platform with plastic followed by a tarp?

MountainDon

Quote from: georgevacabin on October 22, 2008, 08:20:44 PM

So will the OSB be okay for a month if I cover the platform with plastic followed by a tarp?

Nobody's is going to tell you it will be okay; if they do I'm not sure you should believe them. My experience with plastic on the floor was terrible. I was fortunate in that we were there virtually full time and we could sweep it off, lift the tarps to let the ever present leaks dry out, do some work, then cover it before the next rain. Repeat every day for a week - ten days.

How much will it likely rain there in the next month?
Just because something has been done and has not failed, doesn't mean it is good design.


Redoverfarm

George I would try to locate any low spots (rolling a marble or cylinder shape object)and drill some holes at any location that proves to be low)to let it drain.  I would also go and get a cheap paint roller, waterproof sealer and give it a coat or two of something before tarping.  If you could elivate the center of the cabin floor (2X4 or 4X4 end to end of the floor at the middle laying flat on the floor) then stretch the tarp to the both edges and tack onto your rim joist to allow the water to run off both sides. Most tarps laid flat will find the low spots with water pooling but by elivating even slightly will allow it to find gravity. Consider the tarp a throwaway so attach it fairly good on the sides to prevent the wind from getting under it.  A tarp is a small expense considering the alternative.

glenn kangiser

I think John and Don are right - sealer - paint - holes are a good bet - Tarps nearly always seem to have problems.  In the air they also make a great whipping sail I have found.
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

Please put your area in your sig line so we can assist with location specific answers.

JoshF

 When I bought my house it needed a floor in the mud room. So for temporary until I could get it covered I sealed the osb i put down with some cheap deck sealer. Not expecting it to help much.  That was 6 years ago I have never covered it and it is still holding up flawlessly. That room doesnt get direct rain or snow but it has no heat and gets lots of snow and mud tracked in. I would say it was well worth the time and effort to use the sealer. When I build the addition Im planning  I will certainly use deck sealer on it. Maybe even a name brand this time. :)

Redoverfarm

Josh be finished with the worry and get some Advantex or Surefloor.  By the time you buy the sealer and the time to apply you would have the difference in the cost.

MountainDon

Let me just add that I could not find Advantex in NM. The closest place was in Colorado Springs; too far away.

IF I could have picked it up locally I would have definitely, absolutely used it and avoided the water worries.

There was one local place who could have special ordered it, but the minimum was 40-some sheets, way more than I could use even if NM_Shooter and I went in together.
Just because something has been done and has not failed, doesn't mean it is good design.

Redoverfarm

Yeah sort of like me trying to buy the material for an adobe house in the east.


georgevacabin

Hello Folks,

Dropped in to say thanks for the support.  I ended up not using paint/sealer/etc. as I couldn't find anything that would dry quick enough.  I had to leave the property @ 1pm that day.  I covered everything with two layers of 6mil plastic - raised in the middle as Red suggested.  I'll be back down after Thanksgiving.  Keeping my fingers crossed until then. :D